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class="vector-toc-link" href="#Classical_mechanics"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.1</span> <span>Classical mechanics</span> </div> </a> <ul id="toc-Classical_mechanics-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Chemistry" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Chemistry"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.2</span> <span>Chemistry</span> </div> </a> <ul id="toc-Chemistry-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Biology" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Biology"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.3</span> <span>Biology</span> </div> </a> <ul id="toc-Biology-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Earth_sciences" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Earth_sciences"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.4</span> <span>Earth sciences</span> </div> </a> <ul id="toc-Earth_sciences-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Cosmology" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Cosmology"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.5</span> <span>Cosmology</span> </div> </a> <ul id="toc-Cosmology-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Quantum_mechanics" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Quantum_mechanics"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.6</span> <span>Quantum mechanics</span> </div> </a> <ul id="toc-Quantum_mechanics-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Relativity" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Relativity"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.7</span> <span>Relativity</span> </div> </a> <ul id="toc-Relativity-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Transformation" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Transformation"> <div class="vector-toc-text"> <span class="vector-toc-numb">5</span> <span>Transformation</span> </div> </a> <button aria-controls="toc-Transformation-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Transformation subsection</span> </button> <ul id="toc-Transformation-sublist" class="vector-toc-list"> <li id="toc-Conservation_of_energy_and_mass_in_transformation" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Conservation_of_energy_and_mass_in_transformation"> <div class="vector-toc-text"> <span class="vector-toc-numb">5.1</span> <span>Conservation of energy and mass in transformation</span> </div> </a> <ul id="toc-Conservation_of_energy_and_mass_in_transformation-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Reversible_and_non-reversible_transformations" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Reversible_and_non-reversible_transformations"> <div class="vector-toc-text"> <span class="vector-toc-numb">5.2</span> <span>Reversible and non-reversible transformations</span> </div> </a> <ul id="toc-Reversible_and_non-reversible_transformations-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Conservation_of_energy" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Conservation_of_energy"> <div class="vector-toc-text"> <span class="vector-toc-numb">6</span> <span>Conservation of energy</span> </div> </a> <ul id="toc-Conservation_of_energy-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Energy_transfer" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Energy_transfer"> <div class="vector-toc-text"> <span class="vector-toc-numb">7</span> <span>Energy transfer</span> </div> </a> <button aria-controls="toc-Energy_transfer-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Energy transfer subsection</span> </button> <ul id="toc-Energy_transfer-sublist" class="vector-toc-list"> <li id="toc-Closed_systems" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Closed_systems"> <div class="vector-toc-text"> <span class="vector-toc-numb">7.1</span> <span>Closed systems</span> </div> </a> <ul id="toc-Closed_systems-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Open_systems" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Open_systems"> <div class="vector-toc-text"> <span class="vector-toc-numb">7.2</span> <span>Open systems</span> </div> </a> <ul id="toc-Open_systems-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Thermodynamics" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Thermodynamics"> <div class="vector-toc-text"> <span class="vector-toc-numb">8</span> <span>Thermodynamics</span> </div> </a> <button aria-controls="toc-Thermodynamics-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Thermodynamics subsection</span> </button> <ul id="toc-Thermodynamics-sublist" class="vector-toc-list"> <li id="toc-Internal_energy" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Internal_energy"> <div class="vector-toc-text"> <span class="vector-toc-numb">8.1</span> <span>Internal energy</span> </div> </a> <ul id="toc-Internal_energy-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-First_law_of_thermodynamics" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#First_law_of_thermodynamics"> <div class="vector-toc-text"> <span class="vector-toc-numb">8.2</span> <span>First law of thermodynamics</span> </div> </a> <ul id="toc-First_law_of_thermodynamics-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Equipartition_of_energy" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Equipartition_of_energy"> <div class="vector-toc-text"> <span class="vector-toc-numb">8.3</span> <span>Equipartition of energy</span> </div> </a> <ul id="toc-Equipartition_of_energy-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-See_also" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#See_also"> <div class="vector-toc-text"> <span class="vector-toc-numb">9</span> <span>See also</span> </div> </a> <ul id="toc-See_also-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Notes" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Notes"> <div class="vector-toc-text"> <span class="vector-toc-numb">10</span> <span>Notes</span> </div> </a> <ul id="toc-Notes-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-References" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#References"> <div class="vector-toc-text"> <span class="vector-toc-numb">11</span> <span>References</span> </div> </a> <ul id="toc-References-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Further_reading" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Further_reading"> <div class="vector-toc-text"> <span class="vector-toc-numb">12</span> <span>Further reading</span> </div> </a> <button aria-controls="toc-Further_reading-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Further reading subsection</span> </button> <ul id="toc-Further_reading-sublist" class="vector-toc-list"> <li id="toc-Journals" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Journals"> <div class="vector-toc-text"> <span class="vector-toc-numb">12.1</span> <span>Journals</span> </div> </a> <ul id="toc-Journals-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-External_links" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#External_links"> <div class="vector-toc-text"> <span class="vector-toc-numb">13</span> <span>External links</span> </div> </a> <ul id="toc-External_links-sublist" class="vector-toc-list"> </ul> </li> </ul> </div> </div> </nav> </div> </div> <div class="mw-content-container"> <main id="content" class="mw-body"> <header class="mw-body-header vector-page-titlebar"> <nav aria-label="Contents" class="vector-toc-landmark"> <div id="vector-page-titlebar-toc" class="vector-dropdown vector-page-titlebar-toc vector-button-flush-left" > <input type="checkbox" id="vector-page-titlebar-toc-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-titlebar-toc" class="vector-dropdown-checkbox " aria-label="Toggle the table of contents" > <label id="vector-page-titlebar-toc-label" for="vector-page-titlebar-toc-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-listBullet mw-ui-icon-wikimedia-listBullet"></span> <span class="vector-dropdown-label-text">Toggle the table of contents</span> </label> <div class="vector-dropdown-content"> <div id="vector-page-titlebar-toc-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <h1 id="firstHeading" class="firstHeading mw-first-heading"><span class="mw-page-title-main">Energy</span></h1> <div id="p-lang-btn" class="vector-dropdown mw-portlet mw-portlet-lang" > <input type="checkbox" id="p-lang-btn-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-p-lang-btn" class="vector-dropdown-checkbox mw-interlanguage-selector" aria-label="Go to an article in another language. Available in 169 languages" > <label id="p-lang-btn-label" for="p-lang-btn-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--action-progressive mw-portlet-lang-heading-169" aria-hidden="true" ><span class="vector-icon mw-ui-icon-language-progressive mw-ui-icon-wikimedia-language-progressive"></span> <span class="vector-dropdown-label-text">169 languages</span> </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-ace mw-list-item"><a href="https://ace.wikipedia.org/wiki/%C3%89nerji" title="Énerji – Acehnese" lang="ace" hreflang="ace" data-title="Énerji" data-language-autonym="Acèh" data-language-local-name="Acehnese" class="interlanguage-link-target"><span>Acèh</span></a></li><li class="interlanguage-link interwiki-af mw-list-item"><a href="https://af.wikipedia.org/wiki/Energie" title="Energie – Afrikaans" lang="af" hreflang="af" data-title="Energie" data-language-autonym="Afrikaans" data-language-local-name="Afrikaans" class="interlanguage-link-target"><span>Afrikaans</span></a></li><li class="interlanguage-link interwiki-als mw-list-item"><a href="https://als.wikipedia.org/wiki/Energie" title="Energie – Alemannic" lang="gsw" hreflang="gsw" data-title="Energie" data-language-autonym="Alemannisch" data-language-local-name="Alemannic" class="interlanguage-link-target"><span>Alemannisch</span></a></li><li class="interlanguage-link interwiki-am mw-list-item"><a href="https://am.wikipedia.org/wiki/%E1%8A%A0%E1%89%85%E1%88%9D" title="አቅም – Amharic" lang="am" hreflang="am" data-title="አቅም" data-language-autonym="አማርኛ" data-language-local-name="Amharic" class="interlanguage-link-target"><span>አማርኛ</span></a></li><li class="interlanguage-link interwiki-smn mw-list-item"><a href="https://smn.wikipedia.org/wiki/Energia" title="Energia – Inari Sami" lang="smn" hreflang="smn" data-title="Energia" data-language-autonym="Anarâškielâ" data-language-local-name="Inari Sami" class="interlanguage-link-target"><span>Anarâškielâ</span></a></li><li class="interlanguage-link interwiki-ar mw-list-item"><a href="https://ar.wikipedia.org/wiki/%D8%B7%D8%A7%D9%82%D8%A9" title="طاقة – Arabic" lang="ar" hreflang="ar" data-title="طاقة" data-language-autonym="العربية" data-language-local-name="Arabic" class="interlanguage-link-target"><span>العربية</span></a></li><li class="interlanguage-link interwiki-an mw-list-item"><a href="https://an.wikipedia.org/wiki/Enerch%C3%ADa" title="Enerchía – Aragonese" lang="an" hreflang="an" data-title="Enerchía" data-language-autonym="Aragonés" data-language-local-name="Aragonese" class="interlanguage-link-target"><span>Aragonés</span></a></li><li class="interlanguage-link interwiki-arc mw-list-item"><a href="https://arc.wikipedia.org/wiki/%DC%AC%DC%98%DC%A9%DC%A6%DC%90" title="ܬܘܩܦܐ – Aramaic" lang="arc" hreflang="arc" data-title="ܬܘܩܦܐ" data-language-autonym="ܐܪܡܝܐ" data-language-local-name="Aramaic" class="interlanguage-link-target"><span>ܐܪܡܝܐ</span></a></li><li class="interlanguage-link interwiki-as mw-list-item"><a href="https://as.wikipedia.org/wiki/%E0%A6%B6%E0%A6%95%E0%A7%8D%E0%A6%A4%E0%A6%BF" title="শক্তি – Assamese" lang="as" hreflang="as" data-title="শক্তি" data-language-autonym="অসমীয়া" data-language-local-name="Assamese" class="interlanguage-link-target"><span>অসমীয়া</span></a></li><li class="interlanguage-link interwiki-ast mw-list-item"><a href="https://ast.wikipedia.org/wiki/Enerx%C3%ADa" title="Enerxía – Asturian" lang="ast" hreflang="ast" data-title="Enerxía" data-language-autonym="Asturianu" data-language-local-name="Asturian" class="interlanguage-link-target"><span>Asturianu</span></a></li><li class="interlanguage-link interwiki-gn mw-list-item"><a href="https://gn.wikipedia.org/wiki/Mbaretekue" title="Mbaretekue – Guarani" lang="gn" hreflang="gn" data-title="Mbaretekue" data-language-autonym="Avañe'ẽ" data-language-local-name="Guarani" class="interlanguage-link-target"><span>Avañe'ẽ</span></a></li><li class="interlanguage-link interwiki-az mw-list-item"><a href="https://az.wikipedia.org/wiki/Enerji" title="Enerji – Azerbaijani" lang="az" hreflang="az" data-title="Enerji" data-language-autonym="Azərbaycanca" data-language-local-name="Azerbaijani" class="interlanguage-link-target"><span>Azərbaycanca</span></a></li><li class="interlanguage-link interwiki-azb mw-list-item"><a href="https://azb.wikipedia.org/wiki/%D8%A7%D9%86%D8%B1%DA%98%DB%8C" title="انرژی – South Azerbaijani" lang="azb" hreflang="azb" data-title="انرژی" data-language-autonym="تۆرکجه" data-language-local-name="South Azerbaijani" class="interlanguage-link-target"><span>تۆرکجه</span></a></li><li class="interlanguage-link interwiki-bn mw-list-item"><a href="https://bn.wikipedia.org/wiki/%E0%A6%B6%E0%A6%95%E0%A7%8D%E0%A6%A4%E0%A6%BF" title="শক্তি – Bangla" lang="bn" hreflang="bn" data-title="শক্তি" data-language-autonym="বাংলা" data-language-local-name="Bangla" class="interlanguage-link-target"><span>বাংলা</span></a></li><li class="interlanguage-link interwiki-zh-min-nan mw-list-item"><a href="https://zh-min-nan.wikipedia.org/wiki/L%C3%AAng-li%C5%8Dng" title="Lêng-liōng – Minnan" lang="nan" hreflang="nan" data-title="Lêng-liōng" data-language-autonym="閩南語 / Bân-lâm-gú" data-language-local-name="Minnan" class="interlanguage-link-target"><span>閩南語 / Bân-lâm-gú</span></a></li><li class="interlanguage-link interwiki-ba mw-list-item"><a href="https://ba.wikipedia.org/wiki/%D0%AD%D0%BD%D0%B5%D1%80%D0%B3%D0%B8%D1%8F" title="Энергия – Bashkir" lang="ba" hreflang="ba" data-title="Энергия" data-language-autonym="Башҡортса" data-language-local-name="Bashkir" class="interlanguage-link-target"><span>Башҡортса</span></a></li><li class="interlanguage-link interwiki-be mw-list-item"><a href="https://be.wikipedia.org/wiki/%D0%AD%D0%BD%D0%B5%D1%80%D0%B3%D1%96%D1%8F" title="Энергія – Belarusian" lang="be" hreflang="be" data-title="Энергія" data-language-autonym="Беларуская" data-language-local-name="Belarusian" class="interlanguage-link-target"><span>Беларуская</span></a></li><li class="interlanguage-link interwiki-be-x-old mw-list-item"><a href="https://be-tarask.wikipedia.org/wiki/%D0%AD%D0%BD%D1%8D%D1%80%D0%B3%D1%96%D1%8F" title="Энэргія – Belarusian (Taraškievica orthography)" lang="be-tarask" hreflang="be-tarask" data-title="Энэргія" data-language-autonym="Беларуская (тарашкевіца)" data-language-local-name="Belarusian (Taraškievica orthography)" class="interlanguage-link-target"><span>Беларуская (тарашкевіца)</span></a></li><li class="interlanguage-link interwiki-bh mw-list-item"><a href="https://bh.wikipedia.org/wiki/%E0%A4%8A%E0%A4%B0%E0%A5%8D%E0%A4%9C%E0%A4%BE" title="ऊर्जा – Bhojpuri" lang="bh" hreflang="bh" data-title="ऊर्जा" data-language-autonym="भोजपुरी" data-language-local-name="Bhojpuri" class="interlanguage-link-target"><span>भोजपुरी</span></a></li><li class="interlanguage-link interwiki-bcl mw-list-item"><a href="https://bcl.wikipedia.org/wiki/Enerhiya" title="Enerhiya – Central Bikol" lang="bcl" hreflang="bcl" data-title="Enerhiya" data-language-autonym="Bikol Central" data-language-local-name="Central Bikol" class="interlanguage-link-target"><span>Bikol Central</span></a></li><li class="interlanguage-link interwiki-bg mw-list-item"><a href="https://bg.wikipedia.org/wiki/%D0%95%D0%BD%D0%B5%D1%80%D0%B3%D0%B8%D1%8F" title="Енергия – Bulgarian" lang="bg" hreflang="bg" data-title="Енергия" data-language-autonym="Български" data-language-local-name="Bulgarian" class="interlanguage-link-target"><span>Български</span></a></li><li class="interlanguage-link interwiki-bar mw-list-item"><a href="https://bar.wikipedia.org/wiki/Energie" title="Energie – Bavarian" lang="bar" hreflang="bar" data-title="Energie" data-language-autonym="Boarisch" data-language-local-name="Bavarian" class="interlanguage-link-target"><span>Boarisch</span></a></li><li class="interlanguage-link interwiki-bs mw-list-item"><a href="https://bs.wikipedia.org/wiki/Energija" title="Energija – Bosnian" lang="bs" hreflang="bs" data-title="Energija" data-language-autonym="Bosanski" data-language-local-name="Bosnian" class="interlanguage-link-target"><span>Bosanski</span></a></li><li class="interlanguage-link interwiki-br mw-list-item"><a href="https://br.wikipedia.org/wiki/Energiezh" title="Energiezh – Breton" lang="br" hreflang="br" data-title="Energiezh" data-language-autonym="Brezhoneg" data-language-local-name="Breton" class="interlanguage-link-target"><span>Brezhoneg</span></a></li><li class="interlanguage-link interwiki-ca mw-list-item"><a href="https://ca.wikipedia.org/wiki/Energia" title="Energia – Catalan" lang="ca" hreflang="ca" data-title="Energia" data-language-autonym="Català" data-language-local-name="Catalan" class="interlanguage-link-target"><span>Català</span></a></li><li class="interlanguage-link interwiki-cv mw-list-item"><a href="https://cv.wikipedia.org/wiki/%D0%AD%D0%BD%D0%B5%D1%80%D0%B3%D0%B8" title="Энерги – Chuvash" lang="cv" hreflang="cv" data-title="Энерги" data-language-autonym="Чӑвашла" data-language-local-name="Chuvash" class="interlanguage-link-target"><span>Чӑвашла</span></a></li><li class="interlanguage-link interwiki-ceb mw-list-item"><a href="https://ceb.wikipedia.org/wiki/Enerhiya" title="Enerhiya – Cebuano" lang="ceb" hreflang="ceb" data-title="Enerhiya" data-language-autonym="Cebuano" data-language-local-name="Cebuano" class="interlanguage-link-target"><span>Cebuano</span></a></li><li class="interlanguage-link interwiki-cs mw-list-item"><a href="https://cs.wikipedia.org/wiki/Energie" title="Energie – Czech" lang="cs" hreflang="cs" data-title="Energie" data-language-autonym="Čeština" data-language-local-name="Czech" class="interlanguage-link-target"><span>Čeština</span></a></li><li class="interlanguage-link interwiki-sn mw-list-item"><a href="https://sn.wikipedia.org/wiki/Simba" title="Simba – Shona" lang="sn" hreflang="sn" data-title="Simba" data-language-autonym="ChiShona" data-language-local-name="Shona" class="interlanguage-link-target"><span>ChiShona</span></a></li><li class="interlanguage-link interwiki-cy mw-list-item"><a href="https://cy.wikipedia.org/wiki/Egni_(gwyddonol)" title="Egni (gwyddonol) – Welsh" lang="cy" hreflang="cy" data-title="Egni (gwyddonol)" data-language-autonym="Cymraeg" data-language-local-name="Welsh" class="interlanguage-link-target"><span>Cymraeg</span></a></li><li class="interlanguage-link interwiki-da mw-list-item"><a href="https://da.wikipedia.org/wiki/Energi" title="Energi – Danish" lang="da" hreflang="da" data-title="Energi" data-language-autonym="Dansk" data-language-local-name="Danish" class="interlanguage-link-target"><span>Dansk</span></a></li><li class="interlanguage-link interwiki-ary mw-list-item"><a href="https://ary.wikipedia.org/wiki/%D8%B7%D8%A7%D9%82%D8%A9" title="طاقة – Moroccan Arabic" lang="ary" hreflang="ary" data-title="طاقة" data-language-autonym="الدارجة" data-language-local-name="Moroccan Arabic" class="interlanguage-link-target"><span>الدارجة</span></a></li><li class="interlanguage-link interwiki-de mw-list-item"><a href="https://de.wikipedia.org/wiki/Energie" title="Energie – German" lang="de" hreflang="de" data-title="Energie" data-language-autonym="Deutsch" data-language-local-name="German" class="interlanguage-link-target"><span>Deutsch</span></a></li><li class="interlanguage-link interwiki-et mw-list-item"><a href="https://et.wikipedia.org/wiki/Energia" title="Energia – Estonian" lang="et" hreflang="et" data-title="Energia" data-language-autonym="Eesti" data-language-local-name="Estonian" class="interlanguage-link-target"><span>Eesti</span></a></li><li class="interlanguage-link interwiki-el mw-list-item"><a href="https://el.wikipedia.org/wiki/%CE%95%CE%BD%CE%AD%CF%81%CE%B3%CE%B5%CE%B9%CE%B1" title="Ενέργεια – Greek" lang="el" hreflang="el" data-title="Ενέργεια" data-language-autonym="Ελληνικά" data-language-local-name="Greek" class="interlanguage-link-target"><span>Ελληνικά</span></a></li><li class="interlanguage-link interwiki-myv mw-list-item"><a href="https://myv.wikipedia.org/wiki/%D0%90%D0%BB%D1%8C%D0%BC%D0%B5" title="Альме – Erzya" lang="myv" hreflang="myv" data-title="Альме" data-language-autonym="Эрзянь" data-language-local-name="Erzya" class="interlanguage-link-target"><span>Эрзянь</span></a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikipedia.org/wiki/Energ%C3%ADa" title="Energía – Spanish" lang="es" hreflang="es" data-title="Energía" data-language-autonym="Español" data-language-local-name="Spanish" class="interlanguage-link-target"><span>Español</span></a></li><li class="interlanguage-link interwiki-eo mw-list-item"><a href="https://eo.wikipedia.org/wiki/Energio" title="Energio – Esperanto" lang="eo" hreflang="eo" data-title="Energio" data-language-autonym="Esperanto" data-language-local-name="Esperanto" class="interlanguage-link-target"><span>Esperanto</span></a></li><li class="interlanguage-link interwiki-ext mw-list-item"><a href="https://ext.wikipedia.org/wiki/Nirg%C3%ADa" title="Nirgía – Extremaduran" lang="ext" hreflang="ext" data-title="Nirgía" data-language-autonym="Estremeñu" data-language-local-name="Extremaduran" class="interlanguage-link-target"><span>Estremeñu</span></a></li><li class="interlanguage-link interwiki-eu mw-list-item"><a href="https://eu.wikipedia.org/wiki/Energia" title="Energia – Basque" lang="eu" hreflang="eu" data-title="Energia" data-language-autonym="Euskara" data-language-local-name="Basque" class="interlanguage-link-target"><span>Euskara</span></a></li><li class="interlanguage-link interwiki-fa mw-list-item"><a href="https://fa.wikipedia.org/wiki/%D8%A7%D9%86%D8%B1%DA%98%DB%8C" title="انرژی – Persian" lang="fa" hreflang="fa" data-title="انرژی" data-language-autonym="فارسی" data-language-local-name="Persian" class="interlanguage-link-target"><span>فارسی</span></a></li><li class="interlanguage-link interwiki-hif mw-list-item"><a href="https://hif.wikipedia.org/wiki/Shakti" title="Shakti – Fiji Hindi" lang="hif" hreflang="hif" data-title="Shakti" data-language-autonym="Fiji Hindi" data-language-local-name="Fiji Hindi" class="interlanguage-link-target"><span>Fiji Hindi</span></a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/%C3%89nergie_(physique)" title="Énergie (physique) – French" lang="fr" hreflang="fr" data-title="Énergie (physique)" data-language-autonym="Français" data-language-local-name="French" class="interlanguage-link-target"><span>Français</span></a></li><li class="interlanguage-link interwiki-fy mw-list-item"><a href="https://fy.wikipedia.org/wiki/Enerzjy" title="Enerzjy – Western Frisian" lang="fy" hreflang="fy" data-title="Enerzjy" data-language-autonym="Frysk" data-language-local-name="Western Frisian" class="interlanguage-link-target"><span>Frysk</span></a></li><li class="interlanguage-link interwiki-ga mw-list-item"><a href="https://ga.wikipedia.org/wiki/Fuinneamh" title="Fuinneamh – Irish" lang="ga" hreflang="ga" data-title="Fuinneamh" data-language-autonym="Gaeilge" data-language-local-name="Irish" class="interlanguage-link-target"><span>Gaeilge</span></a></li><li class="interlanguage-link interwiki-gv mw-list-item"><a href="https://gv.wikipedia.org/wiki/Bree" title="Bree – Manx" lang="gv" hreflang="gv" data-title="Bree" data-language-autonym="Gaelg" data-language-local-name="Manx" class="interlanguage-link-target"><span>Gaelg</span></a></li><li class="interlanguage-link interwiki-gd mw-list-item"><a href="https://gd.wikipedia.org/wiki/L%C3%B9th" title="Lùth – Scottish Gaelic" lang="gd" hreflang="gd" data-title="Lùth" data-language-autonym="Gàidhlig" data-language-local-name="Scottish Gaelic" class="interlanguage-link-target"><span>Gàidhlig</span></a></li><li class="interlanguage-link interwiki-gl mw-list-item"><a href="https://gl.wikipedia.org/wiki/Enerx%C3%ADa" title="Enerxía – Galician" lang="gl" hreflang="gl" data-title="Enerxía" data-language-autonym="Galego" data-language-local-name="Galician" class="interlanguage-link-target"><span>Galego</span></a></li><li class="interlanguage-link interwiki-inh mw-list-item"><a href="https://inh.wikipedia.org/wiki/%D0%A5%D1%8C%D0%B8%D0%BD%D0%B0%D1%80" title="Хьинар – Ingush" lang="inh" hreflang="inh" data-title="Хьинар" data-language-autonym="ГӀалгӀай" data-language-local-name="Ingush" class="interlanguage-link-target"><span>ГӀалгӀай</span></a></li><li class="interlanguage-link interwiki-gu mw-list-item"><a href="https://gu.wikipedia.org/wiki/%E0%AA%89%E0%AA%B0%E0%AB%8D%E0%AA%9C%E0%AA%BE" title="ઉર્જા – Gujarati" lang="gu" hreflang="gu" data-title="ઉર્જા" data-language-autonym="ગુજરાતી" data-language-local-name="Gujarati" class="interlanguage-link-target"><span>ગુજરાતી</span></a></li><li class="interlanguage-link interwiki-hak mw-list-item"><a href="https://hak.wikipedia.org/wiki/N%C3%A8n-li%C3%B2ng" title="Nèn-liòng – Hakka Chinese" lang="hak" hreflang="hak" data-title="Nèn-liòng" data-language-autonym="客家語 / Hak-kâ-ngî" data-language-local-name="Hakka Chinese" class="interlanguage-link-target"><span>客家語 / Hak-kâ-ngî</span></a></li><li class="interlanguage-link interwiki-ko mw-list-item"><a href="https://ko.wikipedia.org/wiki/%EC%97%90%EB%84%88%EC%A7%80" title="에너지 – Korean" lang="ko" hreflang="ko" data-title="에너지" data-language-autonym="한국어" data-language-local-name="Korean" class="interlanguage-link-target"><span>한국어</span></a></li><li class="interlanguage-link interwiki-ha mw-list-item"><a href="https://ha.wikipedia.org/wiki/Makamashi" title="Makamashi – Hausa" lang="ha" hreflang="ha" data-title="Makamashi" data-language-autonym="Hausa" data-language-local-name="Hausa" class="interlanguage-link-target"><span>Hausa</span></a></li><li class="interlanguage-link interwiki-hy mw-list-item"><a href="https://hy.wikipedia.org/wiki/%D4%B7%D5%B6%D5%A5%D6%80%D5%A3%D5%AB%D5%A1" title="Էներգիա – Armenian" lang="hy" hreflang="hy" data-title="Էներգիա" data-language-autonym="Հայերեն" data-language-local-name="Armenian" class="interlanguage-link-target"><span>Հայերեն</span></a></li><li class="interlanguage-link interwiki-hi mw-list-item"><a href="https://hi.wikipedia.org/wiki/%E0%A4%8A%E0%A4%B0%E0%A5%8D%E0%A4%9C%E0%A4%BE" title="ऊर्जा – Hindi" lang="hi" hreflang="hi" data-title="ऊर्जा" data-language-autonym="हिन्दी" data-language-local-name="Hindi" class="interlanguage-link-target"><span>हिन्दी</span></a></li><li class="interlanguage-link interwiki-hr mw-list-item"><a href="https://hr.wikipedia.org/wiki/Energija" title="Energija – Croatian" lang="hr" hreflang="hr" data-title="Energija" data-language-autonym="Hrvatski" data-language-local-name="Croatian" class="interlanguage-link-target"><span>Hrvatski</span></a></li><li class="interlanguage-link interwiki-io mw-list-item"><a href="https://io.wikipedia.org/wiki/Energio" title="Energio – Ido" lang="io" hreflang="io" data-title="Energio" data-language-autonym="Ido" data-language-local-name="Ido" class="interlanguage-link-target"><span>Ido</span></a></li><li class="interlanguage-link interwiki-ilo mw-list-item"><a href="https://ilo.wikipedia.org/wiki/Enerhia" title="Enerhia – Iloko" lang="ilo" hreflang="ilo" data-title="Enerhia" data-language-autonym="Ilokano" data-language-local-name="Iloko" class="interlanguage-link-target"><span>Ilokano</span></a></li><li class="interlanguage-link interwiki-id mw-list-item"><a href="https://id.wikipedia.org/wiki/Energi" title="Energi – Indonesian" lang="id" hreflang="id" data-title="Energi" data-language-autonym="Bahasa Indonesia" data-language-local-name="Indonesian" class="interlanguage-link-target"><span>Bahasa Indonesia</span></a></li><li class="interlanguage-link interwiki-ia mw-list-item"><a href="https://ia.wikipedia.org/wiki/Energia" title="Energia – Interlingua" lang="ia" hreflang="ia" data-title="Energia" data-language-autonym="Interlingua" data-language-local-name="Interlingua" class="interlanguage-link-target"><span>Interlingua</span></a></li><li class="interlanguage-link interwiki-ie mw-list-item"><a href="https://ie.wikipedia.org/wiki/Energie" title="Energie – Interlingue" lang="ie" hreflang="ie" data-title="Energie" data-language-autonym="Interlingue" data-language-local-name="Interlingue" class="interlanguage-link-target"><span>Interlingue</span></a></li><li class="interlanguage-link interwiki-zu mw-list-item"><a href="https://zu.wikipedia.org/wiki/Isidlakalasi" title="Isidlakalasi – Zulu" lang="zu" hreflang="zu" data-title="Isidlakalasi" data-language-autonym="IsiZulu" data-language-local-name="Zulu" class="interlanguage-link-target"><span>IsiZulu</span></a></li><li class="interlanguage-link interwiki-is badge-Q17437798 badge-goodarticle mw-list-item" title="good article badge"><a href="https://is.wikipedia.org/wiki/Orka" title="Orka – Icelandic" lang="is" hreflang="is" data-title="Orka" data-language-autonym="Íslenska" data-language-local-name="Icelandic" class="interlanguage-link-target"><span>Íslenska</span></a></li><li class="interlanguage-link interwiki-it mw-list-item"><a href="https://it.wikipedia.org/wiki/Energia" title="Energia – Italian" lang="it" hreflang="it" data-title="Energia" data-language-autonym="Italiano" data-language-local-name="Italian" class="interlanguage-link-target"><span>Italiano</span></a></li><li class="interlanguage-link interwiki-he mw-list-item"><a href="https://he.wikipedia.org/wiki/%D7%90%D7%A0%D7%A8%D7%92%D7%99%D7%94" title="אנרגיה – Hebrew" lang="he" hreflang="he" data-title="אנרגיה" data-language-autonym="עברית" data-language-local-name="Hebrew" class="interlanguage-link-target"><span>עברית</span></a></li><li class="interlanguage-link interwiki-jv mw-list-item"><a href="https://jv.wikipedia.org/wiki/%C3%88nergi" title="Ènergi – Javanese" lang="jv" hreflang="jv" data-title="Ènergi" data-language-autonym="Jawa" data-language-local-name="Javanese" class="interlanguage-link-target"><span>Jawa</span></a></li><li class="interlanguage-link interwiki-kn mw-list-item"><a href="https://kn.wikipedia.org/wiki/%E0%B2%B6%E0%B2%95%E0%B3%8D%E0%B2%A4%E0%B2%BF" title="ಶಕ್ತಿ – Kannada" lang="kn" hreflang="kn" data-title="ಶಕ್ತಿ" data-language-autonym="ಕನ್ನಡ" data-language-local-name="Kannada" class="interlanguage-link-target"><span>ಕನ್ನಡ</span></a></li><li class="interlanguage-link interwiki-ka mw-list-item"><a href="https://ka.wikipedia.org/wiki/%E1%83%94%E1%83%9C%E1%83%94%E1%83%A0%E1%83%92%E1%83%98%E1%83%90" title="ენერგია – Georgian" lang="ka" hreflang="ka" data-title="ენერგია" data-language-autonym="ქართული" data-language-local-name="Georgian" class="interlanguage-link-target"><span>ქართული</span></a></li><li class="interlanguage-link interwiki-kk mw-list-item"><a href="https://kk.wikipedia.org/wiki/%D0%AD%D0%BD%D0%B5%D1%80%D0%B3%D0%B8%D1%8F" title="Энергия – Kazakh" lang="kk" hreflang="kk" data-title="Энергия" data-language-autonym="Қазақша" data-language-local-name="Kazakh" class="interlanguage-link-target"><span>Қазақша</span></a></li><li class="interlanguage-link interwiki-kw mw-list-item"><a href="https://kw.wikipedia.org/wiki/Nerth" title="Nerth – Cornish" lang="kw" hreflang="kw" data-title="Nerth" data-language-autonym="Kernowek" data-language-local-name="Cornish" class="interlanguage-link-target"><span>Kernowek</span></a></li><li class="interlanguage-link interwiki-sw mw-list-item"><a href="https://sw.wikipedia.org/wiki/Nishati" title="Nishati – Swahili" lang="sw" hreflang="sw" data-title="Nishati" data-language-autonym="Kiswahili" data-language-local-name="Swahili" class="interlanguage-link-target"><span>Kiswahili</span></a></li><li class="interlanguage-link interwiki-ht mw-list-item"><a href="https://ht.wikipedia.org/wiki/En%C3%A8ji" title="Enèji – Haitian Creole" lang="ht" hreflang="ht" data-title="Enèji" data-language-autonym="Kreyòl ayisyen" data-language-local-name="Haitian Creole" class="interlanguage-link-target"><span>Kreyòl ayisyen</span></a></li><li class="interlanguage-link interwiki-gcr mw-list-item"><a href="https://gcr.wikipedia.org/wiki/%C3%89nerji" title="Énerji – Guianan Creole" lang="gcr" hreflang="gcr" data-title="Énerji" data-language-autonym="Kriyòl gwiyannen" data-language-local-name="Guianan Creole" class="interlanguage-link-target"><span>Kriyòl gwiyannen</span></a></li><li class="interlanguage-link interwiki-ku mw-list-item"><a href="https://ku.wikipedia.org/wiki/Wize" title="Wize – Kurdish" lang="ku" hreflang="ku" data-title="Wize" data-language-autonym="Kurdî" data-language-local-name="Kurdish" class="interlanguage-link-target"><span>Kurdî</span></a></li><li class="interlanguage-link interwiki-ky mw-list-item"><a href="https://ky.wikipedia.org/wiki/%D0%AD%D0%BD%D0%B5%D1%80%D0%B3%D0%B8%D1%8F" title="Энергия – Kyrgyz" lang="ky" hreflang="ky" data-title="Энергия" data-language-autonym="Кыргызча" data-language-local-name="Kyrgyz" class="interlanguage-link-target"><span>Кыргызча</span></a></li><li class="interlanguage-link interwiki-lo mw-list-item"><a href="https://lo.wikipedia.org/wiki/%E0%BA%9E%E0%BA%B0%E0%BA%A5%E0%BA%B1%E0%BA%87%E0%BA%87%E0%BA%B2%E0%BA%99" title="ພະລັງງານ – Lao" lang="lo" hreflang="lo" data-title="ພະລັງງານ" data-language-autonym="ລາວ" data-language-local-name="Lao" class="interlanguage-link-target"><span>ລາວ</span></a></li><li class="interlanguage-link interwiki-la mw-list-item"><a href="https://la.wikipedia.org/wiki/Energia" title="Energia – Latin" lang="la" hreflang="la" data-title="Energia" data-language-autonym="Latina" data-language-local-name="Latin" class="interlanguage-link-target"><span>Latina</span></a></li><li class="interlanguage-link interwiki-lv mw-list-item"><a href="https://lv.wikipedia.org/wiki/Ener%C4%A3ija" title="Enerģija – Latvian" lang="lv" hreflang="lv" data-title="Enerģija" data-language-autonym="Latviešu" data-language-local-name="Latvian" class="interlanguage-link-target"><span>Latviešu</span></a></li><li class="interlanguage-link interwiki-lb mw-list-item"><a href="https://lb.wikipedia.org/wiki/Energie" title="Energie – Luxembourgish" lang="lb" hreflang="lb" data-title="Energie" data-language-autonym="Lëtzebuergesch" data-language-local-name="Luxembourgish" class="interlanguage-link-target"><span>Lëtzebuergesch</span></a></li><li class="interlanguage-link interwiki-lt mw-list-item"><a href="https://lt.wikipedia.org/wiki/Energija" title="Energija – Lithuanian" lang="lt" hreflang="lt" data-title="Energija" data-language-autonym="Lietuvių" data-language-local-name="Lithuanian" class="interlanguage-link-target"><span>Lietuvių</span></a></li><li class="interlanguage-link interwiki-li mw-list-item"><a href="https://li.wikipedia.org/wiki/Energie" title="Energie – Limburgish" lang="li" hreflang="li" data-title="Energie" data-language-autonym="Limburgs" data-language-local-name="Limburgish" class="interlanguage-link-target"><span>Limburgs</span></a></li><li class="interlanguage-link interwiki-ln mw-list-item"><a href="https://ln.wikipedia.org/wiki/Molung%C3%A9" title="Molungé – Lingala" lang="ln" hreflang="ln" data-title="Molungé" data-language-autonym="Lingála" data-language-local-name="Lingala" class="interlanguage-link-target"><span>Lingála</span></a></li><li class="interlanguage-link interwiki-lg mw-list-item"><a href="https://lg.wikipedia.org/wiki/Energy" title="Energy – Ganda" lang="lg" hreflang="lg" data-title="Energy" data-language-autonym="Luganda" data-language-local-name="Ganda" class="interlanguage-link-target"><span>Luganda</span></a></li><li class="interlanguage-link interwiki-lmo mw-list-item"><a href="https://lmo.wikipedia.org/wiki/Energia" title="Energia – Lombard" lang="lmo" hreflang="lmo" data-title="Energia" data-language-autonym="Lombard" data-language-local-name="Lombard" class="interlanguage-link-target"><span>Lombard</span></a></li><li class="interlanguage-link interwiki-hu mw-list-item"><a href="https://hu.wikipedia.org/wiki/Energia" title="Energia – Hungarian" lang="hu" hreflang="hu" data-title="Energia" data-language-autonym="Magyar" data-language-local-name="Hungarian" class="interlanguage-link-target"><span>Magyar</span></a></li><li class="interlanguage-link interwiki-mk mw-list-item"><a href="https://mk.wikipedia.org/wiki/%D0%95%D0%BD%D0%B5%D1%80%D0%B3%D0%B8%D1%98%D0%B0" title="Енергија – Macedonian" lang="mk" hreflang="mk" data-title="Енергија" data-language-autonym="Македонски" data-language-local-name="Macedonian" class="interlanguage-link-target"><span>Македонски</span></a></li><li class="interlanguage-link interwiki-mg mw-list-item"><a href="https://mg.wikipedia.org/wiki/Ang%C3%B4vo" title="Angôvo – Malagasy" lang="mg" hreflang="mg" data-title="Angôvo" data-language-autonym="Malagasy" data-language-local-name="Malagasy" class="interlanguage-link-target"><span>Malagasy</span></a></li><li class="interlanguage-link interwiki-ml mw-list-item"><a href="https://ml.wikipedia.org/wiki/%E0%B4%8A%E0%B5%BC%E0%B4%9C%E0%B5%8D%E0%B4%9C%E0%B4%82" title="ഊർജ്ജം – Malayalam" lang="ml" hreflang="ml" data-title="ഊർജ്ജം" data-language-autonym="മലയാളം" data-language-local-name="Malayalam" class="interlanguage-link-target"><span>മലയാളം</span></a></li><li class="interlanguage-link interwiki-mr mw-list-item"><a href="https://mr.wikipedia.org/wiki/%E0%A4%8A%E0%A4%B0%E0%A5%8D%E0%A4%9C%E0%A4%BE" title="ऊर्जा – Marathi" lang="mr" hreflang="mr" data-title="ऊर्जा" data-language-autonym="मराठी" data-language-local-name="Marathi" class="interlanguage-link-target"><span>मराठी</span></a></li><li class="interlanguage-link interwiki-xmf mw-list-item"><a href="https://xmf.wikipedia.org/wiki/%E1%83%94%E1%83%9C%E1%83%94%E1%83%A0%E1%83%92%E1%83%98%E1%83%90" title="ენერგია – Mingrelian" lang="xmf" hreflang="xmf" data-title="ენერგია" data-language-autonym="მარგალური" data-language-local-name="Mingrelian" class="interlanguage-link-target"><span>მარგალური</span></a></li><li class="interlanguage-link interwiki-arz mw-list-item"><a href="https://arz.wikipedia.org/wiki/%D8%B7%D8%A7%D9%82%D9%87" title="طاقه – Egyptian Arabic" lang="arz" hreflang="arz" data-title="طاقه" data-language-autonym="مصرى" data-language-local-name="Egyptian Arabic" class="interlanguage-link-target"><span>مصرى</span></a></li><li class="interlanguage-link interwiki-mzn mw-list-item"><a href="https://mzn.wikipedia.org/wiki/%D8%A7%D9%86%D8%B1%DA%98%DB%8C" title="انرژی – Mazanderani" lang="mzn" hreflang="mzn" data-title="انرژی" data-language-autonym="مازِرونی" data-language-local-name="Mazanderani" class="interlanguage-link-target"><span>مازِرونی</span></a></li><li class="interlanguage-link interwiki-ms mw-list-item"><a href="https://ms.wikipedia.org/wiki/Tenaga" title="Tenaga – Malay" lang="ms" hreflang="ms" data-title="Tenaga" data-language-autonym="Bahasa Melayu" data-language-local-name="Malay" class="interlanguage-link-target"><span>Bahasa Melayu</span></a></li><li class="interlanguage-link interwiki-mwl mw-list-item"><a href="https://mwl.wikipedia.org/wiki/Einergie" title="Einergie – Mirandese" lang="mwl" hreflang="mwl" data-title="Einergie" data-language-autonym="Mirandés" data-language-local-name="Mirandese" class="interlanguage-link-target"><span>Mirandés</span></a></li><li class="interlanguage-link interwiki-mn mw-list-item"><a href="https://mn.wikipedia.org/wiki/%D0%AD%D0%BD%D0%B5%D1%80%D0%B3%D0%B8" title="Энерги – Mongolian" lang="mn" hreflang="mn" data-title="Энерги" data-language-autonym="Монгол" data-language-local-name="Mongolian" class="interlanguage-link-target"><span>Монгол</span></a></li><li class="interlanguage-link interwiki-my mw-list-item"><a href="https://my.wikipedia.org/wiki/%E1%80%85%E1%80%BD%E1%80%99%E1%80%BA%E1%80%B8%E1%80%A1%E1%80%84%E1%80%BA" title="စွမ်းအင် – Burmese" lang="my" hreflang="my" data-title="စွမ်းအင်" data-language-autonym="မြန်မာဘာသာ" data-language-local-name="Burmese" class="interlanguage-link-target"><span>မြန်မာဘာသာ</span></a></li><li class="interlanguage-link interwiki-fj mw-list-item"><a href="https://fj.wikipedia.org/wiki/Igu" title="Igu – Fijian" lang="fj" hreflang="fj" data-title="Igu" data-language-autonym="Na Vosa Vakaviti" data-language-local-name="Fijian" class="interlanguage-link-target"><span>Na Vosa Vakaviti</span></a></li><li class="interlanguage-link interwiki-nl mw-list-item"><a href="https://nl.wikipedia.org/wiki/Energie" title="Energie – Dutch" lang="nl" hreflang="nl" data-title="Energie" data-language-autonym="Nederlands" data-language-local-name="Dutch" class="interlanguage-link-target"><span>Nederlands</span></a></li><li class="interlanguage-link interwiki-ne mw-list-item"><a href="https://ne.wikipedia.org/wiki/%E0%A4%8A%E0%A4%B0%E0%A5%8D%E0%A4%9C%E0%A4%BE" title="ऊर्जा – Nepali" lang="ne" hreflang="ne" data-title="ऊर्जा" data-language-autonym="नेपाली" data-language-local-name="Nepali" class="interlanguage-link-target"><span>नेपाली</span></a></li><li class="interlanguage-link interwiki-new mw-list-item"><a href="https://new.wikipedia.org/wiki/%E0%A4%8A%E0%A4%B0%E0%A5%8D%E0%A4%9C%E0%A4%BE" title="ऊर्जा – Newari" lang="new" hreflang="new" data-title="ऊर्जा" data-language-autonym="नेपाल भाषा" data-language-local-name="Newari" class="interlanguage-link-target"><span>नेपाल भाषा</span></a></li><li class="interlanguage-link interwiki-ja mw-list-item"><a href="https://ja.wikipedia.org/wiki/%E3%82%A8%E3%83%8D%E3%83%AB%E3%82%AE%E3%83%BC" title="エネルギー – Japanese" lang="ja" hreflang="ja" data-title="エネルギー" data-language-autonym="日本語" data-language-local-name="Japanese" class="interlanguage-link-target"><span>日本語</span></a></li><li class="interlanguage-link interwiki-ce mw-list-item"><a href="https://ce.wikipedia.org/wiki/%D0%AD%D0%BD%D0%B5%D1%80%D0%B3%D0%B8" title="Энерги – Chechen" lang="ce" hreflang="ce" data-title="Энерги" data-language-autonym="Нохчийн" data-language-local-name="Chechen" class="interlanguage-link-target"><span>Нохчийн</span></a></li><li class="interlanguage-link interwiki-frr badge-Q17437798 badge-goodarticle mw-list-item" title="good article badge"><a href="https://frr.wikipedia.org/wiki/Energii" title="Energii – Northern Frisian" lang="frr" hreflang="frr" data-title="Energii" data-language-autonym="Nordfriisk" data-language-local-name="Northern Frisian" class="interlanguage-link-target"><span>Nordfriisk</span></a></li><li class="interlanguage-link interwiki-no mw-list-item"><a href="https://no.wikipedia.org/wiki/Energi" title="Energi – Norwegian Bokmål" lang="nb" hreflang="nb" data-title="Energi" data-language-autonym="Norsk bokmål" data-language-local-name="Norwegian Bokmål" class="interlanguage-link-target"><span>Norsk bokmål</span></a></li><li class="interlanguage-link interwiki-nn mw-list-item"><a href="https://nn.wikipedia.org/wiki/Energi" title="Energi – Norwegian Nynorsk" lang="nn" hreflang="nn" data-title="Energi" data-language-autonym="Norsk nynorsk" data-language-local-name="Norwegian Nynorsk" class="interlanguage-link-target"><span>Norsk nynorsk</span></a></li><li class="interlanguage-link interwiki-nov mw-list-item"><a href="https://nov.wikipedia.org/wiki/Energie" title="Energie – Novial" lang="nov" hreflang="nov" data-title="Energie" data-language-autonym="Novial" data-language-local-name="Novial" class="interlanguage-link-target"><span>Novial</span></a></li><li class="interlanguage-link interwiki-oc mw-list-item"><a href="https://oc.wikipedia.org/wiki/Energia" title="Energia – Occitan" lang="oc" hreflang="oc" data-title="Energia" data-language-autonym="Occitan" data-language-local-name="Occitan" class="interlanguage-link-target"><span>Occitan</span></a></li><li class="interlanguage-link interwiki-or mw-list-item"><a href="https://or.wikipedia.org/wiki/%E0%AC%B6%E0%AC%95%E0%AD%8D%E0%AC%A4%E0%AC%BF" title="ଶକ୍ତି – Odia" lang="or" hreflang="or" data-title="ଶକ୍ତି" data-language-autonym="ଓଡ଼ିଆ" data-language-local-name="Odia" class="interlanguage-link-target"><span>ଓଡ଼ିଆ</span></a></li><li class="interlanguage-link interwiki-om mw-list-item"><a href="https://om.wikipedia.org/wiki/Anniisaa" title="Anniisaa – Oromo" lang="om" hreflang="om" data-title="Anniisaa" data-language-autonym="Oromoo" data-language-local-name="Oromo" class="interlanguage-link-target"><span>Oromoo</span></a></li><li class="interlanguage-link interwiki-uz mw-list-item"><a href="https://uz.wikipedia.org/wiki/Energiya" title="Energiya – Uzbek" lang="uz" hreflang="uz" data-title="Energiya" data-language-autonym="Oʻzbekcha / ўзбекча" data-language-local-name="Uzbek" class="interlanguage-link-target"><span>Oʻzbekcha / ўзбекча</span></a></li><li class="interlanguage-link interwiki-pa mw-list-item"><a href="https://pa.wikipedia.org/wiki/%E0%A8%8A%E0%A8%B0%E0%A8%9C%E0%A8%BE" title="ਊਰਜਾ – Punjabi" lang="pa" hreflang="pa" data-title="ਊਰਜਾ" data-language-autonym="ਪੰਜਾਬੀ" data-language-local-name="Punjabi" class="interlanguage-link-target"><span>ਪੰਜਾਬੀ</span></a></li><li class="interlanguage-link interwiki-pnb mw-list-item"><a href="https://pnb.wikipedia.org/wiki/%D8%AA%D9%88%D8%A7%D9%86%D8%A7%D8%A6%DB%8C" title="توانائی – Western Punjabi" lang="pnb" hreflang="pnb" data-title="توانائی" data-language-autonym="پنجابی" data-language-local-name="Western Punjabi" class="interlanguage-link-target"><span>پنجابی</span></a></li><li class="interlanguage-link interwiki-ps mw-list-item"><a href="https://ps.wikipedia.org/wiki/%D8%A7%D9%86%D8%B1%DA%98%D9%8A" title="انرژي – Pashto" lang="ps" hreflang="ps" data-title="انرژي" data-language-autonym="پښتو" data-language-local-name="Pashto" class="interlanguage-link-target"><span>پښتو</span></a></li><li class="interlanguage-link interwiki-jam mw-list-item"><a href="https://jam.wikipedia.org/wiki/Enaji" title="Enaji – Jamaican Creole English" lang="jam" hreflang="jam" data-title="Enaji" data-language-autonym="Patois" data-language-local-name="Jamaican Creole English" class="interlanguage-link-target"><span>Patois</span></a></li><li class="interlanguage-link interwiki-pms mw-list-item"><a href="https://pms.wikipedia.org/wiki/Energ%C3%ACa" title="Energìa – Piedmontese" lang="pms" hreflang="pms" data-title="Energìa" data-language-autonym="Piemontèis" data-language-local-name="Piedmontese" class="interlanguage-link-target"><span>Piemontèis</span></a></li><li class="interlanguage-link interwiki-tpi mw-list-item"><a href="https://tpi.wikipedia.org/wiki/Eneji" title="Eneji – Tok Pisin" lang="tpi" hreflang="tpi" data-title="Eneji" data-language-autonym="Tok Pisin" data-language-local-name="Tok Pisin" class="interlanguage-link-target"><span>Tok Pisin</span></a></li><li class="interlanguage-link interwiki-nds mw-list-item"><a href="https://nds.wikipedia.org/wiki/Energie" title="Energie – Low German" lang="nds" hreflang="nds" data-title="Energie" data-language-autonym="Plattdüütsch" data-language-local-name="Low German" class="interlanguage-link-target"><span>Plattdüütsch</span></a></li><li class="interlanguage-link interwiki-pl mw-list-item"><a href="https://pl.wikipedia.org/wiki/Energia" title="Energia – Polish" lang="pl" hreflang="pl" data-title="Energia" data-language-autonym="Polski" data-language-local-name="Polish" class="interlanguage-link-target"><span>Polski</span></a></li><li class="interlanguage-link interwiki-pt mw-list-item"><a href="https://pt.wikipedia.org/wiki/Energia" title="Energia – Portuguese" lang="pt" hreflang="pt" data-title="Energia" data-language-autonym="Português" data-language-local-name="Portuguese" class="interlanguage-link-target"><span>Português</span></a></li><li class="interlanguage-link interwiki-kaa mw-list-item"><a href="https://kaa.wikipedia.org/wiki/Energiya" title="Energiya – Kara-Kalpak" lang="kaa" hreflang="kaa" data-title="Energiya" data-language-autonym="Qaraqalpaqsha" data-language-local-name="Kara-Kalpak" class="interlanguage-link-target"><span>Qaraqalpaqsha</span></a></li><li class="interlanguage-link interwiki-ro mw-list-item"><a href="https://ro.wikipedia.org/wiki/Energie" title="Energie – Romanian" lang="ro" hreflang="ro" data-title="Energie" data-language-autonym="Română" data-language-local-name="Romanian" class="interlanguage-link-target"><span>Română</span></a></li><li class="interlanguage-link interwiki-rm mw-list-item"><a href="https://rm.wikipedia.org/wiki/Energia" title="Energia – Romansh" lang="rm" hreflang="rm" data-title="Energia" data-language-autonym="Rumantsch" data-language-local-name="Romansh" class="interlanguage-link-target"><span>Rumantsch</span></a></li><li class="interlanguage-link interwiki-qu mw-list-item"><a href="https://qu.wikipedia.org/wiki/Micha" title="Micha – Quechua" lang="qu" hreflang="qu" data-title="Micha" data-language-autonym="Runa Simi" data-language-local-name="Quechua" class="interlanguage-link-target"><span>Runa Simi</span></a></li><li class="interlanguage-link interwiki-rue mw-list-item"><a href="https://rue.wikipedia.org/wiki/%D0%95%D0%BD%D0%B5%D1%80%D2%91%D1%96%D1%8F" title="Енерґія – Rusyn" lang="rue" hreflang="rue" data-title="Енерґія" data-language-autonym="Русиньскый" data-language-local-name="Rusyn" class="interlanguage-link-target"><span>Русиньскый</span></a></li><li class="interlanguage-link interwiki-ru mw-list-item"><a href="https://ru.wikipedia.org/wiki/%D0%AD%D0%BD%D0%B5%D1%80%D0%B3%D0%B8%D1%8F" title="Энергия – Russian" lang="ru" hreflang="ru" data-title="Энергия" data-language-autonym="Русский" data-language-local-name="Russian" class="interlanguage-link-target"><span>Русский</span></a></li><li class="interlanguage-link interwiki-sah mw-list-item"><a href="https://sah.wikipedia.org/wiki/%D0%AD%D0%BD%D0%B5%D1%80%D0%B3%D0%B8%D1%8F" title="Энергия – Yakut" lang="sah" hreflang="sah" data-title="Энергия" data-language-autonym="Саха тыла" data-language-local-name="Yakut" class="interlanguage-link-target"><span>Саха тыла</span></a></li><li class="interlanguage-link interwiki-sco mw-list-item"><a href="https://sco.wikipedia.org/wiki/Energy" title="Energy – Scots" lang="sco" hreflang="sco" data-title="Energy" data-language-autonym="Scots" data-language-local-name="Scots" class="interlanguage-link-target"><span>Scots</span></a></li><li class="interlanguage-link interwiki-sq mw-list-item"><a href="https://sq.wikipedia.org/wiki/Energjia" title="Energjia – Albanian" lang="sq" hreflang="sq" data-title="Energjia" data-language-autonym="Shqip" data-language-local-name="Albanian" class="interlanguage-link-target"><span>Shqip</span></a></li><li class="interlanguage-link interwiki-scn mw-list-item"><a href="https://scn.wikipedia.org/wiki/Enirg%C3%ACa" title="Enirgìa – Sicilian" lang="scn" hreflang="scn" data-title="Enirgìa" data-language-autonym="Sicilianu" data-language-local-name="Sicilian" class="interlanguage-link-target"><span>Sicilianu</span></a></li><li class="interlanguage-link interwiki-si mw-list-item"><a href="https://si.wikipedia.org/wiki/%E0%B7%81%E0%B6%9A%E0%B7%8A%E0%B6%AD%E0%B7%92%E0%B6%BA" title="ශක්තිය – Sinhala" lang="si" hreflang="si" data-title="ශක්තිය" data-language-autonym="සිංහල" data-language-local-name="Sinhala" class="interlanguage-link-target"><span>සිංහල</span></a></li><li class="interlanguage-link interwiki-simple mw-list-item"><a href="https://simple.wikipedia.org/wiki/Energy" title="Energy – Simple English" lang="en-simple" hreflang="en-simple" data-title="Energy" data-language-autonym="Simple English" data-language-local-name="Simple English" class="interlanguage-link-target"><span>Simple English</span></a></li><li class="interlanguage-link interwiki-sd mw-list-item"><a href="https://sd.wikipedia.org/wiki/%D8%AA%D9%88%D8%A7%D9%86%D8%A7%D8%A6%D9%8A" title="توانائي – Sindhi" lang="sd" hreflang="sd" data-title="توانائي" data-language-autonym="سنڌي" data-language-local-name="Sindhi" class="interlanguage-link-target"><span>سنڌي</span></a></li><li class="interlanguage-link interwiki-sk mw-list-item"><a href="https://sk.wikipedia.org/wiki/Energia" title="Energia – Slovak" lang="sk" hreflang="sk" data-title="Energia" data-language-autonym="Slovenčina" data-language-local-name="Slovak" class="interlanguage-link-target"><span>Slovenčina</span></a></li><li class="interlanguage-link interwiki-sl mw-list-item"><a href="https://sl.wikipedia.org/wiki/Energija" title="Energija – Slovenian" lang="sl" hreflang="sl" data-title="Energija" data-language-autonym="Slovenščina" data-language-local-name="Slovenian" class="interlanguage-link-target"><span>Slovenščina</span></a></li><li class="interlanguage-link interwiki-so mw-list-item"><a href="https://so.wikipedia.org/wiki/Tamar" title="Tamar – Somali" lang="so" hreflang="so" data-title="Tamar" data-language-autonym="Soomaaliga" data-language-local-name="Somali" class="interlanguage-link-target"><span>Soomaaliga</span></a></li><li class="interlanguage-link interwiki-ckb mw-list-item"><a href="https://ckb.wikipedia.org/wiki/%D9%88%D8%B2%DB%95" title="وزە – Central Kurdish" lang="ckb" hreflang="ckb" data-title="وزە" data-language-autonym="کوردی" data-language-local-name="Central Kurdish" class="interlanguage-link-target"><span>کوردی</span></a></li><li class="interlanguage-link interwiki-sr mw-list-item"><a href="https://sr.wikipedia.org/wiki/%D0%95%D0%BD%D0%B5%D1%80%D0%B3%D0%B8%D1%98%D0%B0" title="Енергија – Serbian" lang="sr" hreflang="sr" data-title="Енергија" data-language-autonym="Српски / srpski" data-language-local-name="Serbian" class="interlanguage-link-target"><span>Српски / srpski</span></a></li><li class="interlanguage-link interwiki-sh mw-list-item"><a href="https://sh.wikipedia.org/wiki/Energija" title="Energija – Serbo-Croatian" lang="sh" hreflang="sh" data-title="Energija" data-language-autonym="Srpskohrvatski / српскохрватски" data-language-local-name="Serbo-Croatian" class="interlanguage-link-target"><span>Srpskohrvatski / српскохрватски</span></a></li><li class="interlanguage-link interwiki-su mw-list-item"><a href="https://su.wikipedia.org/wiki/%C3%89nergi" title="Énergi – Sundanese" lang="su" hreflang="su" data-title="Énergi" data-language-autonym="Sunda" data-language-local-name="Sundanese" class="interlanguage-link-target"><span>Sunda</span></a></li><li class="interlanguage-link interwiki-fi mw-list-item"><a href="https://fi.wikipedia.org/wiki/Energia" title="Energia – Finnish" lang="fi" hreflang="fi" data-title="Energia" data-language-autonym="Suomi" data-language-local-name="Finnish" class="interlanguage-link-target"><span>Suomi</span></a></li><li class="interlanguage-link interwiki-sv mw-list-item"><a href="https://sv.wikipedia.org/wiki/Energi" title="Energi – Swedish" lang="sv" hreflang="sv" data-title="Energi" data-language-autonym="Svenska" data-language-local-name="Swedish" class="interlanguage-link-target"><span>Svenska</span></a></li><li class="interlanguage-link interwiki-tl mw-list-item"><a href="https://tl.wikipedia.org/wiki/Enerhiya" title="Enerhiya – Tagalog" lang="tl" hreflang="tl" data-title="Enerhiya" data-language-autonym="Tagalog" data-language-local-name="Tagalog" class="interlanguage-link-target"><span>Tagalog</span></a></li><li class="interlanguage-link interwiki-ta mw-list-item"><a href="https://ta.wikipedia.org/wiki/%E0%AE%86%E0%AE%B1%E0%AF%8D%E0%AE%B1%E0%AE%B2%E0%AF%8D" title="ஆற்றல் – Tamil" lang="ta" hreflang="ta" data-title="ஆற்றல்" data-language-autonym="தமிழ்" data-language-local-name="Tamil" class="interlanguage-link-target"><span>தமிழ்</span></a></li><li class="interlanguage-link interwiki-shi mw-list-item"><a href="https://shi.wikipedia.org/wiki/Ta%E1%BA%93%E1%B8%8Da%E1%B9%9Bt" title="Taẓḍaṛt – Tachelhit" lang="shi" hreflang="shi" data-title="Taẓḍaṛt" data-language-autonym="Taclḥit" data-language-local-name="Tachelhit" class="interlanguage-link-target"><span>Taclḥit</span></a></li><li class="interlanguage-link interwiki-kab mw-list-item"><a href="https://kab.wikipedia.org/wiki/Tafasa" title="Tafasa – Kabyle" lang="kab" hreflang="kab" data-title="Tafasa" data-language-autonym="Taqbaylit" data-language-local-name="Kabyle" class="interlanguage-link-target"><span>Taqbaylit</span></a></li><li class="interlanguage-link interwiki-tt mw-list-item"><a href="https://tt.wikipedia.org/wiki/%D0%AD%D0%BD%D0%B5%D1%80%D0%B3%D0%B8%D1%8F" title="Энергия – Tatar" lang="tt" hreflang="tt" data-title="Энергия" data-language-autonym="Татарча / tatarça" data-language-local-name="Tatar" class="interlanguage-link-target"><span>Татарча / tatarça</span></a></li><li class="interlanguage-link interwiki-te mw-list-item"><a href="https://te.wikipedia.org/wiki/%E0%B0%B6%E0%B0%95%E0%B1%8D%E0%B0%A4%E0%B0%BF" title="శక్తి – Telugu" lang="te" hreflang="te" data-title="శక్తి" data-language-autonym="తెలుగు" data-language-local-name="Telugu" class="interlanguage-link-target"><span>తెలుగు</span></a></li><li class="interlanguage-link interwiki-th mw-list-item"><a href="https://th.wikipedia.org/wiki/%E0%B8%9E%E0%B8%A5%E0%B8%B1%E0%B8%87%E0%B8%87%E0%B8%B2%E0%B8%99" title="พลังงาน – Thai" lang="th" hreflang="th" data-title="พลังงาน" data-language-autonym="ไทย" data-language-local-name="Thai" class="interlanguage-link-target"><span>ไทย</span></a></li><li class="interlanguage-link interwiki-tg mw-list-item"><a href="https://tg.wikipedia.org/wiki/%D0%AD%D0%BD%D0%B5%D1%80%D0%B3%D0%B8%D1%8F" title="Энергия – Tajik" lang="tg" hreflang="tg" data-title="Энергия" data-language-autonym="Тоҷикӣ" data-language-local-name="Tajik" class="interlanguage-link-target"><span>Тоҷикӣ</span></a></li><li class="interlanguage-link interwiki-tr mw-list-item"><a href="https://tr.wikipedia.org/wiki/Enerji" title="Enerji – Turkish" lang="tr" hreflang="tr" data-title="Enerji" data-language-autonym="Türkçe" data-language-local-name="Turkish" class="interlanguage-link-target"><span>Türkçe</span></a></li><li class="interlanguage-link interwiki-tk mw-list-item"><a href="https://tk.wikipedia.org/wiki/Energi%C3%BDa" title="Energiýa – Turkmen" lang="tk" hreflang="tk" data-title="Energiýa" data-language-autonym="Türkmençe" data-language-local-name="Turkmen" class="interlanguage-link-target"><span>Türkmençe</span></a></li><li class="interlanguage-link interwiki-tyv mw-list-item"><a href="https://tyv.wikipedia.org/wiki/%D0%AD%D0%BD%D0%B5%D1%80%D0%B3%D0%B8%D1%8F" title="Энергия – Tuvinian" lang="tyv" hreflang="tyv" data-title="Энергия" data-language-autonym="Тыва дыл" data-language-local-name="Tuvinian" class="interlanguage-link-target"><span>Тыва дыл</span></a></li><li class="interlanguage-link interwiki-uk mw-list-item"><a href="https://uk.wikipedia.org/wiki/%D0%95%D0%BD%D0%B5%D1%80%D0%B3%D1%96%D1%8F" title="Енергія – Ukrainian" lang="uk" hreflang="uk" data-title="Енергія" data-language-autonym="Українська" data-language-local-name="Ukrainian" class="interlanguage-link-target"><span>Українська</span></a></li><li class="interlanguage-link interwiki-ur mw-list-item"><a href="https://ur.wikipedia.org/wiki/%D8%AA%D9%88%D8%A7%D9%86%D8%A7%D8%A6%DB%8C" title="توانائی – Urdu" lang="ur" hreflang="ur" data-title="توانائی" data-language-autonym="اردو" data-language-local-name="Urdu" class="interlanguage-link-target"><span>اردو</span></a></li><li class="interlanguage-link interwiki-ug mw-list-item"><a href="https://ug.wikipedia.org/wiki/%D8%A6%DB%90%D9%86%DB%90%D8%B1%DA%AF%D9%89%D9%8A%DB%95" title="ئېنېرگىيە – Uyghur" lang="ug" hreflang="ug" data-title="ئېنېرگىيە" data-language-autonym="ئۇيغۇرچە / Uyghurche" data-language-local-name="Uyghur" class="interlanguage-link-target"><span>ئۇيغۇرچە / Uyghurche</span></a></li><li class="interlanguage-link interwiki-vec mw-list-item"><a href="https://vec.wikipedia.org/wiki/Enerzia" title="Enerzia – Venetian" lang="vec" hreflang="vec" data-title="Enerzia" data-language-autonym="Vèneto" data-language-local-name="Venetian" class="interlanguage-link-target"><span>Vèneto</span></a></li><li class="interlanguage-link interwiki-vep mw-list-item"><a href="https://vep.wikipedia.org/wiki/Energii" title="Energii – Veps" lang="vep" hreflang="vep" data-title="Energii" data-language-autonym="Vepsän kel’" data-language-local-name="Veps" class="interlanguage-link-target"><span>Vepsän kel’</span></a></li><li class="interlanguage-link interwiki-vi mw-list-item"><a href="https://vi.wikipedia.org/wiki/N%C4%83ng_l%C6%B0%E1%BB%A3ng" title="Năng lượng – Vietnamese" lang="vi" hreflang="vi" data-title="Năng lượng" data-language-autonym="Tiếng Việt" data-language-local-name="Vietnamese" class="interlanguage-link-target"><span>Tiếng Việt</span></a></li><li class="interlanguage-link interwiki-vo mw-list-item"><a href="https://vo.wikipedia.org/wiki/N%C3%A4met" title="Nämet – Volapük" lang="vo" hreflang="vo" data-title="Nämet" data-language-autonym="Volapük" data-language-local-name="Volapük" class="interlanguage-link-target"><span>Volapük</span></a></li><li class="interlanguage-link interwiki-zh-classical mw-list-item"><a href="https://zh-classical.wikipedia.org/wiki/%E8%83%BD%E9%87%8F" title="能量 – Literary Chinese" lang="lzh" hreflang="lzh" data-title="能量" data-language-autonym="文言" data-language-local-name="Literary Chinese" class="interlanguage-link-target"><span>文言</span></a></li><li class="interlanguage-link interwiki-war mw-list-item"><a href="https://war.wikipedia.org/wiki/Enerhiya" title="Enerhiya – Waray" lang="war" hreflang="war" data-title="Enerhiya" data-language-autonym="Winaray" data-language-local-name="Waray" class="interlanguage-link-target"><span>Winaray</span></a></li><li class="interlanguage-link interwiki-wo mw-list-item"><a href="https://wo.wikipedia.org/wiki/K%C3%A0ttan" title="Kàttan – Wolof" lang="wo" hreflang="wo" data-title="Kàttan" data-language-autonym="Wolof" data-language-local-name="Wolof" class="interlanguage-link-target"><span>Wolof</span></a></li><li class="interlanguage-link interwiki-wuu mw-list-item"><a href="https://wuu.wikipedia.org/wiki/%E8%83%BD%E9%87%8F" title="能量 – Wu" lang="wuu" hreflang="wuu" data-title="能量" data-language-autonym="吴语" data-language-local-name="Wu" class="interlanguage-link-target"><span>吴语</span></a></li><li class="interlanguage-link interwiki-ts mw-list-item"><a href="https://ts.wikipedia.org/wiki/Matimba" title="Matimba – Tsonga" lang="ts" hreflang="ts" data-title="Matimba" data-language-autonym="Xitsonga" data-language-local-name="Tsonga" class="interlanguage-link-target"><span>Xitsonga</span></a></li><li class="interlanguage-link interwiki-yi mw-list-item"><a href="https://yi.wikipedia.org/wiki/%D7%A2%D7%A0%D7%A2%D7%A8%D7%92%D7%99%D7%A2" title="ענערגיע – Yiddish" lang="yi" hreflang="yi" data-title="ענערגיע" data-language-autonym="ייִדיש" data-language-local-name="Yiddish" class="interlanguage-link-target"><span>ייִדיש</span></a></li><li class="interlanguage-link interwiki-zh-yue mw-list-item"><a href="https://zh-yue.wikipedia.org/wiki/%E8%83%BD%E9%87%8F" title="能量 – Cantonese" lang="yue" hreflang="yue" data-title="能量" data-language-autonym="粵語" data-language-local-name="Cantonese" class="interlanguage-link-target"><span>粵語</span></a></li><li class="interlanguage-link interwiki-bat-smg mw-list-item"><a href="https://bat-smg.wikipedia.org/wiki/Energ%C4%97j%C4%97" title="Energėjė – Samogitian" lang="sgs" hreflang="sgs" data-title="Energėjė" data-language-autonym="Žemaitėška" data-language-local-name="Samogitian" class="interlanguage-link-target"><span>Žemaitėška</span></a></li><li class="interlanguage-link interwiki-zh mw-list-item"><a href="https://zh.wikipedia.org/wiki/%E8%83%BD%E9%87%8F" title="能量 – Chinese" lang="zh" hreflang="zh" data-title="能量" data-language-autonym="中文" data-language-local-name="Chinese" class="interlanguage-link-target"><span>中文</span></a></li><li class="interlanguage-link interwiki-dtp mw-list-item"><a href="https://dtp.wikipedia.org/wiki/Tinori" title="Tinori – Central Dusun" lang="dtp" hreflang="dtp" data-title="Tinori" data-language-autonym="Kadazandusun" data-language-local-name="Central Dusun" class="interlanguage-link-target"><span>Kadazandusun</span></a></li> </ul> <div class="after-portlet after-portlet-lang"><span class="wb-langlinks-edit wb-langlinks-link"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q11379#sitelinks-wikipedia" title="Edit interlanguage links" class="wbc-editpage">Edit links</a></span></div> </div> </div> </div> </header> <div class="vector-page-toolbar"> <div 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quantity</div> <style data-mw-deduplicate="TemplateStyles:r1236090951">.mw-parser-output .hatnote{font-style:italic}.mw-parser-output div.hatnote{padding-left:1.6em;margin-bottom:0.5em}.mw-parser-output .hatnote i{font-style:normal}.mw-parser-output .hatnote+link+.hatnote{margin-top:-0.5em}@media print{body.ns-0 .mw-parser-output .hatnote{display:none!important}}</style><div role="note" class="hatnote navigation-not-searchable">This article is about the scalar physical quantity. For an overview of and topical guide to energy, see <a href="/wiki/Outline_of_energy" title="Outline of energy">Outline of energy</a>. For other uses, see <a href="/wiki/Energy_(disambiguation)" class="mw-disambig" title="Energy (disambiguation)">Energy (disambiguation)</a>.</div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">"Energetic" redirects here. For other uses, see <a href="/wiki/Energetic_(disambiguation)" class="mw-disambig" title="Energetic (disambiguation)">Energetic (disambiguation)</a>.</div> <p class="mw-empty-elt"> </p> <style data-mw-deduplicate="TemplateStyles:r1257001546">.mw-parser-output .infobox-subbox{padding:0;border:none;margin:-3px;width:auto;min-width:100%;font-size:100%;clear:none;float:none;background-color:transparent}.mw-parser-output .infobox-3cols-child{margin:auto}.mw-parser-output .infobox .navbar{font-size:100%}@media screen{html.skin-theme-clientpref-night .mw-parser-output .infobox-full-data:not(.notheme)>div:not(.notheme)[style]{background:#1f1f23!important;color:#f8f9fa}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .infobox-full-data:not(.notheme) div:not(.notheme){background:#1f1f23!important;color:#f8f9fa}}@media(min-width:640px){body.skin--responsive .mw-parser-output .infobox-table{display:table!important}body.skin--responsive .mw-parser-output .infobox-table>caption{display:table-caption!important}body.skin--responsive .mw-parser-output .infobox-table>tbody{display:table-row-group}body.skin--responsive .mw-parser-output .infobox-table tr{display:table-row!important}body.skin--responsive .mw-parser-output .infobox-table th,body.skin--responsive .mw-parser-output .infobox-table td{padding-left:inherit;padding-right:inherit}}</style><table class="infobox"><tbody><tr><th colspan="2" class="infobox-above">Energy</th></tr><tr><td colspan="2" class="infobox-image"><span class="mw-default-size" typeof="mw:File/Frameless"><a href="/wiki/File:Energy_Arc_(central_electrode_of_a_Plasma_Lamp).jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Energy_Arc_%28central_electrode_of_a_Plasma_Lamp%29.jpg/250px-Energy_Arc_%28central_electrode_of_a_Plasma_Lamp%29.jpg" decoding="async" width="250" height="188" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Energy_Arc_%28central_electrode_of_a_Plasma_Lamp%29.jpg/375px-Energy_Arc_%28central_electrode_of_a_Plasma_Lamp%29.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Energy_Arc_%28central_electrode_of_a_Plasma_Lamp%29.jpg/500px-Energy_Arc_%28central_electrode_of_a_Plasma_Lamp%29.jpg 2x" data-file-width="980" data-file-height="735" /></a></span><div class="infobox-caption">A <a href="/wiki/Plasma_globe" title="Plasma globe">plasma globe</a>, using <a href="/wiki/Electrical_energy" title="Electrical energy">electrical energy</a> to create <a href="/wiki/Plasma_(physics)" title="Plasma (physics)">plasma</a>, <a href="/wiki/Light" title="Light">light</a>, <a href="/wiki/Heat" title="Heat">heat</a>, <a href="/wiki/Kinetic_energy" title="Kinetic energy">movement</a> and a faint <a href="/wiki/Sound" title="Sound">sound</a></div></td></tr><tr><th scope="row" class="infobox-label"><div style="display: inline-block; line-height: 1.2em; padding: .1em 0;">Common symbols</div></th><td class="infobox-data"><i>E</i></td></tr><tr><th scope="row" class="infobox-label"><a href="/wiki/SI_unit" class="mw-redirect" title="SI unit">SI unit</a></th><td class="infobox-data"><a href="/wiki/Joule" title="Joule">joule</a></td></tr><tr><th scope="row" class="infobox-label"><div style="display: inline-block; line-height: 1.2em; padding: .1em 0;">Other units</div></th><td class="infobox-data"><a href="/wiki/Kilowatt-hour" title="Kilowatt-hour">kW⋅h</a>, <a href="/wiki/British_Thermal_Unit" class="mw-redirect" title="British Thermal Unit">BTU</a>, <a href="/wiki/Calorie" title="Calorie">calorie</a>, <a href="/wiki/Electronvolt" title="Electronvolt">eV</a>, <a href="/wiki/Erg" title="Erg">erg</a>, <a href="/wiki/Foot-pound_(energy)" title="Foot-pound (energy)">foot-pound</a></td></tr><tr><th scope="row" class="infobox-label">In <a href="/wiki/SI_base_unit" title="SI base unit"><span class="wrap">SI base units</span></a></th><td class="infobox-data">J = kg⋅m<sup>2</sup>⋅s<sup>−2</sup></td></tr><tr><th scope="row" class="infobox-label"><a href="/wiki/Intensive_and_extensive_properties" title="Intensive and extensive properties">Extensive</a>?</th><td class="infobox-data">yes</td></tr><tr><th scope="row" class="infobox-label"><a href="/wiki/Conserved_quantity" title="Conserved quantity">Conserved</a>?</th><td class="infobox-data"><a href="/wiki/Conservation_of_energy" title="Conservation of energy">yes</a></td></tr><tr><th scope="row" class="infobox-label"><a href="/wiki/Dimensional_analysis#Formulation" title="Dimensional analysis">Dimension</a></th><td class="infobox-data"><b>M</b> <b>L</b><sup>2</sup> <b>T</b><sup>−2</sup></td></tr></tbody></table> <style data-mw-deduplicate="TemplateStyles:r1129693374">.mw-parser-output .hlist dl,.mw-parser-output .hlist ol,.mw-parser-output .hlist ul{margin:0;padding:0}.mw-parser-output .hlist dd,.mw-parser-output .hlist dt,.mw-parser-output .hlist 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rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1246091330"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1246091330"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><table class="sidebar sidebar-collapse nomobile nowraplinks plainlist"><tbody><tr><th class="sidebar-title" style="padding-bottom:0.3em;border-bottom:1px solid #aaa;"><a href="/wiki/Thermodynamics" title="Thermodynamics">Thermodynamics</a></th></tr><tr><td class="sidebar-image" style="display:block;margin:0.3em 0 0.4em;"><span class="mw-default-size" typeof="mw:File/Frameless"><a href="/wiki/Carnot_heat_engine" title="Carnot heat engine"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/2/22/Carnot_heat_engine_2.svg/220px-Carnot_heat_engine_2.svg.png" decoding="async" width="220" height="97" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/2/22/Carnot_heat_engine_2.svg/330px-Carnot_heat_engine_2.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/2/22/Carnot_heat_engine_2.svg/440px-Carnot_heat_engine_2.svg.png 2x" data-file-width="840" data-file-height="370" /></a></span><div class="sidebar-caption">The classical <a href="/wiki/Carnot_heat_engine" title="Carnot heat engine">Carnot heat engine</a></div></td></tr><tr><td class="sidebar-content"> <div class="sidebar-list mw-collapsible mw-collapsed"><div class="sidebar-list-title" style="background:#ddf;text-align:center;;color: var(--color-base)">Branches</div><div class="sidebar-list-content mw-collapsible-content"><div class="hlist"> <ul><li><a href="/wiki/Thermodynamics" title="Thermodynamics">Classical</a></li> <li><a href="/wiki/Statistical_mechanics" title="Statistical mechanics">Statistical</a></li> <li><a href="/wiki/Chemical_thermodynamics" title="Chemical thermodynamics">Chemical</a></li> <li><a href="/wiki/Quantum_thermodynamics" title="Quantum thermodynamics">Quantum thermodynamics</a></li></ul> </div> <ul><li><a href="/wiki/Equilibrium_thermodynamics" title="Equilibrium thermodynamics">Equilibrium</a> / <a href="/wiki/Non-equilibrium_thermodynamics" title="Non-equilibrium thermodynamics">Non-equilibrium</a></li></ul></div></div></td> </tr><tr><td class="sidebar-content"> <div class="sidebar-list mw-collapsible mw-collapsed"><div class="sidebar-list-title" style="background:#ddf;text-align:center;;color: var(--color-base)"><a href="/wiki/Laws_of_thermodynamics" title="Laws of thermodynamics">Laws</a></div><div class="sidebar-list-content mw-collapsible-content"><div class="hlist"> <ul><li><a href="/wiki/Zeroth_law_of_thermodynamics" title="Zeroth law of thermodynamics">Zeroth</a></li> <li><a href="/wiki/First_law_of_thermodynamics" title="First law of thermodynamics">First</a></li> <li><a href="/wiki/Second_law_of_thermodynamics" title="Second law of thermodynamics">Second</a></li> <li><a href="/wiki/Third_law_of_thermodynamics" title="Third law of thermodynamics">Third</a></li></ul> </div></div></div></td> </tr><tr><td class="sidebar-content"> <div class="sidebar-list mw-collapsible mw-collapsed"><div class="sidebar-list-title" style="background:#ddf;text-align:center;;color: var(--color-base)"><a href="/wiki/Thermodynamic_system" title="Thermodynamic system">Systems</a></div><div class="sidebar-list-content mw-collapsible-content"> <ul><li><a href="/wiki/Closed_system" title="Closed system">Closed system</a></li> <li><a href="/wiki/Thermodynamic_system#Open_system" title="Thermodynamic system">Open system</a></li> <li><a href="/wiki/Isolated_system" title="Isolated system">Isolated system</a></li></ul> <table class="sidebar nomobile nowraplinks" style="background-color: transparent; color: var( --color-base ); border-collapse:collapse; border-spacing:0px; border:none; width:100%; margin:0px; font-size:100%; clear:none; float:none"><tbody><tr><th class="sidebar-heading" style="background:#eaeaff;font-style:italic;"> <a href="/wiki/Thermodynamic_state" title="Thermodynamic state">State</a></th></tr><tr><td class="sidebar-content hlist"> <ul><li><a href="/wiki/Equation_of_state" title="Equation of state">Equation of state</a></li> <li><a href="/wiki/Ideal_gas" title="Ideal gas">Ideal gas</a></li> <li><a href="/wiki/Real_gas" title="Real gas">Real gas</a></li> <li><a href="/wiki/State_of_matter" title="State of matter">State of matter</a></li> <li><a href="/wiki/Phase_(matter)" title="Phase (matter)">Phase (matter)</a></li> <li><a href="/wiki/Thermodynamic_equilibrium" title="Thermodynamic equilibrium">Equilibrium</a></li> <li><a href="/wiki/Control_volume" title="Control volume">Control volume</a></li> <li><a href="/wiki/Thermodynamic_instruments" title="Thermodynamic instruments">Instruments</a></li></ul></td> </tr><tr><th class="sidebar-heading" style="background:#eaeaff;font-style:italic;"> <a href="/wiki/Thermodynamic_process" title="Thermodynamic process">Processes</a></th></tr><tr><td class="sidebar-content hlist"> <ul><li><a href="/wiki/Isobaric_process" title="Isobaric process">Isobaric</a></li> <li><a href="/wiki/Isochoric_process" title="Isochoric process">Isochoric</a></li> <li><a href="/wiki/Isothermal_process" title="Isothermal process">Isothermal</a></li> <li><a href="/wiki/Adiabatic_process" title="Adiabatic process">Adiabatic</a></li> <li><a href="/wiki/Isentropic_process" title="Isentropic process">Isentropic</a></li> <li><a href="/wiki/Isenthalpic_process" title="Isenthalpic process">Isenthalpic</a></li> <li><a href="/wiki/Quasistatic_process" title="Quasistatic process">Quasistatic</a></li> <li><a href="/wiki/Polytropic_process" title="Polytropic process">Polytropic</a></li> <li><a href="/wiki/Free_expansion" class="mw-redirect" title="Free expansion">Free expansion</a></li> <li><a href="/wiki/Reversible_process_(thermodynamics)" title="Reversible process (thermodynamics)">Reversibility</a></li> <li><a href="/wiki/Irreversible_process" title="Irreversible process">Irreversibility</a></li> <li><a href="/wiki/Endoreversible_thermodynamics" title="Endoreversible thermodynamics">Endoreversibility</a></li></ul></td> </tr><tr><th class="sidebar-heading" style="background:#eaeaff;font-style:italic;"> <a href="/wiki/Thermodynamic_cycle" title="Thermodynamic cycle">Cycles</a></th></tr><tr><td class="sidebar-content hlist"> <ul><li><a href="/wiki/Heat_engine" title="Heat engine">Heat engines</a></li> <li><a href="/wiki/Heat_pump_and_refrigeration_cycle" title="Heat pump and refrigeration cycle">Heat pumps</a></li> <li><a href="/wiki/Thermal_efficiency" title="Thermal efficiency">Thermal efficiency</a></li></ul></td> </tr></tbody></table></div></div></td> </tr><tr><td class="sidebar-content"> <div class="sidebar-list mw-collapsible mw-collapsed"><div class="sidebar-list-title" style="background:#ddf;text-align:center;;color: var(--color-base)"><a href="/wiki/List_of_thermodynamic_properties" title="List of thermodynamic properties">System properties</a></div><div class="sidebar-list-content mw-collapsible-content"><div style="font-size:90%;padding-bottom:0.2em;border-bottom:1px solid #aaa;">Note: <a href="/wiki/Conjugate_variables_(thermodynamics)" title="Conjugate variables (thermodynamics)">Conjugate variables</a> in <i>italics</i></div> <table class="sidebar nomobile nowraplinks" style="background-color: transparent; color: var( --color-base ); border-collapse:collapse; border-spacing:0px; border:none; width:100%; margin:0px; font-size:100%; clear:none; float:none;margin-top:0.4em;"><tbody><tr><td class="sidebar-content" style="padding-bottom:0.7em;"> <ul><li><a href="/wiki/Thermodynamic_diagrams" title="Thermodynamic diagrams">Property diagrams</a></li> <li><a href="/wiki/Intensive_and_extensive_properties" title="Intensive and extensive properties">Intensive and extensive properties</a></li></ul></td> </tr><tr><th class="sidebar-heading" style="background:#eaeaff;font-style:italic;"> <a href="/wiki/Process_function" title="Process function">Process functions</a></th></tr><tr><td class="sidebar-content" style="padding-bottom:0.7em;;padding-bottom:0.4em;"> <div class="hlist"> <ul><li><a href="/wiki/Work_(thermodynamics)" title="Work (thermodynamics)">Work</a></li> <li><a href="/wiki/Heat" title="Heat">Heat</a></li></ul> </div></td> </tr><tr><th class="sidebar-heading" style="background:#eaeaff;font-style:italic;"> <a href="/wiki/State_function" title="State function">Functions of state</a></th></tr><tr><td class="sidebar-content" style="padding-bottom:0.7em;"> <ul><li><a href="/wiki/Thermodynamic_temperature" title="Thermodynamic temperature">Temperature</a> / <i><a href="/wiki/Entropy" title="Entropy">Entropy</a></i> (<a href="/wiki/Introduction_to_entropy" title="Introduction to entropy">introduction</a>)</li> <li><a href="/wiki/Pressure" title="Pressure">Pressure</a> / <i><a href="/wiki/Volume_(thermodynamics)" title="Volume (thermodynamics)">Volume</a></i></li> <li><a href="/wiki/Chemical_potential" title="Chemical potential">Chemical potential</a> / <i><a href="/wiki/Particle_number" title="Particle number">Particle number</a></i></li> <li><a href="/wiki/Vapor_quality" title="Vapor quality">Vapor quality</a></li> <li><a href="/wiki/Reduced_properties" title="Reduced properties">Reduced properties</a></li></ul></td> </tr></tbody></table></div></div></td> </tr><tr><td class="sidebar-content"> <div class="sidebar-list mw-collapsible mw-collapsed"><div class="sidebar-list-title" style="background:#ddf;text-align:center;;color: var(--color-base)"><a href="/wiki/Material_properties_(thermodynamics)" title="Material properties (thermodynamics)">Material properties</a></div><div class="sidebar-list-content mw-collapsible-content"> <ul><li><a href="/wiki/Thermodynamic_databases_for_pure_substances" title="Thermodynamic databases for pure substances">Property databases</a></li></ul> <div style="font-size:90%;margin-top:0.4em;border-top:1px solid #aaa;text-align:center;"> <table> <tbody><tr><td style="vertical-align:middle; text-align:right"><a href="/wiki/Heat_capacity" title="Heat capacity">Specific heat capacity</a> </td> <td style="vertical-align:middle; text-align:left"><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle c=}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>c</mi> <mo>=</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle c=}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/891d40a9b18752b04065caee655d008b3ec11428" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:3.46ex; height:1.676ex;" alt="{\displaystyle c=}"></span></td> <td><table><tbody><tr><td><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle T}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>T</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle T}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/ec7200acd984a1d3a3d7dc455e262fbe54f7f6e0" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.636ex; height:2.176ex;" alt="{\displaystyle T}"></span></td><td><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \partial S}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi mathvariant="normal">∂</mi> <mi>S</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \partial S}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/c609f4d3c5692ea4495479ef47594dc67f9fa464" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:2.817ex; height:2.176ex;" alt="{\displaystyle \partial S}"></span></td></tr><tr><td style="border-top:solid 1px black;"><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle N}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>N</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle N}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/f5e3890c981ae85503089652feb48b191b57aae3" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:2.064ex; height:2.176ex;" alt="{\displaystyle N}"></span></td><td style="border-top:solid 1px black;"><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \partial T}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi mathvariant="normal">∂</mi> <mi>T</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \partial T}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/504aa558fff3d00d10b03cadb1085cb0b7bdc631" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:2.954ex; height:2.176ex;" alt="{\displaystyle \partial T}"></span></td></tr></tbody></table></td></tr> <tr><td style="vertical-align:middle; text-align:right"><a href="/wiki/Compressibility" title="Compressibility">Compressibility</a> </td> <td style="vertical-align:middle; text-align:left"><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \beta =-}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>β</mi> <mo>=</mo> <mo>−</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \beta =-}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/b01c042bf1456bd4d2a8caed1f4912820a7ecbb3" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:6.239ex; height:2.509ex;" alt="{\displaystyle \beta =-}"></span></td> <td><table><tbody><tr><td><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle 1}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mn>1</mn> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle 1}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/92d98b82a3778f043108d4e20960a9193df57cbf" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.162ex; height:2.176ex;" alt="{\displaystyle 1}"></span></td><td><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \partial V}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi mathvariant="normal">∂</mi> <mi>V</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \partial V}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/0cecdd9d069fa84159940068fc11a91b6b3b9ee4" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:3.105ex; height:2.176ex;" alt="{\displaystyle \partial V}"></span></td></tr><tr><td style="border-top:solid 1px black;"><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle V}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>V</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle V}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/af0f6064540e84211d0ffe4dac72098adfa52845" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.787ex; height:2.176ex;" alt="{\displaystyle V}"></span></td><td style="border-top:solid 1px black;"><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \partial p}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi mathvariant="normal">∂</mi> <mi>p</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \partial p}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/ebc4a48eb2412f08b54fe438b5139c88f9cfa372" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:2.487ex; height:2.509ex;" alt="{\displaystyle \partial p}"></span></td></tr></tbody></table></td></tr> <tr><td style="vertical-align:middle; text-align:right"><a href="/wiki/Thermal_expansion" title="Thermal expansion">Thermal expansion</a> </td> <td style="vertical-align:middle; text-align:left"><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \alpha =}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>α</mi> <mo>=</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \alpha =}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/a92d4583d351f08c1c70985f0c843b2fff1b01e7" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:3.941ex; height:1.676ex;" alt="{\displaystyle \alpha =}"></span></td> <td><table><tbody><tr><td><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle 1}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mn>1</mn> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle 1}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/92d98b82a3778f043108d4e20960a9193df57cbf" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.162ex; height:2.176ex;" alt="{\displaystyle 1}"></span></td><td><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \partial V}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi mathvariant="normal">∂</mi> <mi>V</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \partial V}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/0cecdd9d069fa84159940068fc11a91b6b3b9ee4" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:3.105ex; height:2.176ex;" alt="{\displaystyle \partial V}"></span></td></tr><tr><td style="border-top:solid 1px black;"><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle V}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>V</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle V}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/af0f6064540e84211d0ffe4dac72098adfa52845" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.787ex; height:2.176ex;" alt="{\displaystyle V}"></span></td><td style="border-top:solid 1px black;"><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \partial T}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi mathvariant="normal">∂</mi> <mi>T</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \partial T}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/504aa558fff3d00d10b03cadb1085cb0b7bdc631" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:2.954ex; height:2.176ex;" alt="{\displaystyle \partial T}"></span></td></tr></tbody></table></td></tr> </tbody></table></div></div></div></td> </tr><tr><td class="sidebar-content"> <div class="sidebar-list mw-collapsible mw-collapsed"><div class="sidebar-list-title" style="background:#ddf;text-align:center;;color: var(--color-base)"><a href="/wiki/Thermodynamic_equations" title="Thermodynamic equations">Equations</a></div><div class="sidebar-list-content mw-collapsible-content"><div class="hlist"> <ul><li><a href="/wiki/Carnot%27s_theorem_(thermodynamics)" title="Carnot's theorem (thermodynamics)">Carnot's theorem</a></li> <li><a href="/wiki/Clausius_theorem" title="Clausius theorem">Clausius theorem</a></li> <li><a href="/wiki/Fundamental_thermodynamic_relation" title="Fundamental thermodynamic relation">Fundamental relation</a></li> <li><a href="/wiki/Ideal_gas_law" title="Ideal gas law">Ideal gas law</a></li></ul> </div> <ul><li><a href="/wiki/Maxwell_relations" title="Maxwell relations">Maxwell relations</a></li> <li><a href="/wiki/Onsager_reciprocal_relations" title="Onsager reciprocal relations">Onsager reciprocal relations</a></li> <li><a href="/wiki/Bridgman%27s_thermodynamic_equations" title="Bridgman's thermodynamic equations">Bridgman's equations</a></li> <li><i><a href="/wiki/Table_of_thermodynamic_equations" title="Table of thermodynamic equations">Table of thermodynamic equations</a></i></li></ul></div></div></td> </tr><tr><td class="sidebar-content"> <div class="sidebar-list mw-collapsible mw-collapsed"><div class="sidebar-list-title" style="background:#ddf;text-align:center;;color: var(--color-base)"><a href="/wiki/Thermodynamic_potential" title="Thermodynamic potential">Potentials</a></div><div class="sidebar-list-content mw-collapsible-content"><div class="hlist"> <ul><li><a href="/wiki/Thermodynamic_free_energy" title="Thermodynamic free energy">Free energy</a></li> <li><a href="/wiki/Free_entropy" title="Free entropy">Free entropy</a></li></ul> </div> <div class="plainlist"><ul><li style="font-size:110%;line-height:1.6em;padding-bottom:0.5em;"><a href="/wiki/Internal_energy" title="Internal energy">Internal energy</a><br /><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle U(S,V)}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>U</mi> <mo stretchy="false">(</mo> <mi>S</mi> <mo>,</mo> <mi>V</mi> <mo stretchy="false">)</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle U(S,V)}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/921f33f9c6551562ec836007b035c2de6323d2d6" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:7.912ex; height:2.843ex;" alt="{\displaystyle U(S,V)}"></span></li><li style="font-size:110%;line-height:1.6em;padding-bottom:0.5em;"><a href="/wiki/Enthalpy" title="Enthalpy">Enthalpy</a><br /><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle H(S,p)=U+pV}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>H</mi> <mo stretchy="false">(</mo> <mi>S</mi> <mo>,</mo> <mi>p</mi> <mo stretchy="false">)</mo> <mo>=</mo> <mi>U</mi> <mo>+</mo> <mi>p</mi> <mi>V</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle H(S,p)=U+pV}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/6407d78e5f39d07f70e2414a92e08e2e068519f3" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:18.254ex; height:2.843ex;" alt="{\displaystyle H(S,p)=U+pV}"></span></li><li style="font-size:110%;line-height:1.6em;padding-bottom:0.5em;"><a href="/wiki/Helmholtz_free_energy" title="Helmholtz free energy">Helmholtz free energy</a><br /><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle A(T,V)=U-TS}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>A</mi> <mo stretchy="false">(</mo> <mi>T</mi> <mo>,</mo> <mi>V</mi> <mo stretchy="false">)</mo> <mo>=</mo> <mi>U</mi> <mo>−</mo> <mi>T</mi> <mi>S</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle A(T,V)=U-TS}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/5e93692f031ba6484d82731c54db83a69daed3f0" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:18.867ex; height:2.843ex;" alt="{\displaystyle A(T,V)=U-TS}"></span></li><li style="font-size:110%;line-height:1.6em;padding-bottom:0.5em;"><a href="/wiki/Gibbs_free_energy" title="Gibbs free energy">Gibbs free energy</a><br /><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle G(T,p)=H-TS}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>G</mi> <mo stretchy="false">(</mo> <mi>T</mi> <mo>,</mo> <mi>p</mi> <mo stretchy="false">)</mo> <mo>=</mo> <mi>H</mi> <mo>−</mo> <mi>T</mi> <mi>S</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle G(T,p)=H-TS}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/8dd7a8f0b8ae04963da133e3b202432e1b6caed4" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.838ex; width:18.614ex; height:2.843ex;" alt="{\displaystyle G(T,p)=H-TS}"></span></li></ul></div></div></div></td> </tr><tr><td class="sidebar-content"> <div class="sidebar-list mw-collapsible mw-collapsed"><div class="sidebar-list-title" style="background:#ddf;text-align:center;;color: var(--color-base)"><div class="hlist"><ul><li>History</li><li>Culture</li></ul></div></div><div class="sidebar-list-content mw-collapsible-content"><table class="sidebar nomobile nowraplinks" style="background-color: transparent; color: var( --color-base ); border-collapse:collapse; border-spacing:0px; border:none; width:100%; margin:0px; font-size:100%; clear:none; float:none"><tbody><tr><th class="sidebar-heading" style="background:#eaeaff;font-style:italic;"> History</th></tr><tr><td class="sidebar-content"> <div class="hlist"> <ul><li><a href="/wiki/History_of_thermodynamics" title="History of thermodynamics">General</a></li> <li><a href="/wiki/History_of_entropy" title="History of entropy">Entropy</a></li> <li><a href="/wiki/Gas_laws" title="Gas laws">Gas laws</a></li></ul> </div> <ul><li><a href="/wiki/History_of_perpetual_motion_machines" title="History of perpetual motion machines">"Perpetual motion" machines</a></li></ul></td> </tr><tr><th class="sidebar-heading" style="background:#eaeaff;font-style:italic;"> <a href="/wiki/Philosophy_of_thermal_and_statistical_physics" class="mw-redirect" title="Philosophy of thermal and statistical physics">Philosophy</a></th></tr><tr><td class="sidebar-content"> <div class="hlist"> <ul><li><a href="/wiki/Entropy_(arrow_of_time)" class="mw-redirect" title="Entropy (arrow of time)">Entropy and time</a></li> <li><a href="/wiki/Entropy_and_life" title="Entropy and life">Entropy and life</a></li> <li><a href="/wiki/Brownian_ratchet" title="Brownian ratchet">Brownian ratchet</a></li> <li><a href="/wiki/Maxwell%27s_demon" title="Maxwell's demon">Maxwell's demon</a></li> <li><a href="/wiki/Heat_death_paradox" title="Heat death paradox">Heat death paradox</a></li> <li><a href="/wiki/Loschmidt%27s_paradox" title="Loschmidt's paradox">Loschmidt's paradox</a></li> <li><a href="/wiki/Synergetics_(Haken)" title="Synergetics (Haken)">Synergetics</a></li></ul> </div></td> </tr><tr><th class="sidebar-heading" style="background:#eaeaff;font-style:italic;"> Theories</th></tr><tr><td class="sidebar-content"> <div class="hlist"> <ul><li><a href="/wiki/Caloric_theory" title="Caloric theory">Caloric theory</a></li></ul> </div> <ul><li><a href="/wiki/Vis_viva" title="Vis viva"><i>Vis viva</i> <span style="font-size:85%;">("living force")</span></a></li> <li><a href="/wiki/Mechanical_equivalent_of_heat" title="Mechanical equivalent of heat">Mechanical equivalent of heat</a></li> <li><a href="/wiki/Power_(physics)" title="Power (physics)">Motive power</a></li></ul></td> </tr><tr><th class="sidebar-heading" style="background:#eaeaff;font-style:italic;"> <a href="/wiki/List_of_important_publications_in_physics" title="List of important publications in physics">Key publications</a></th></tr><tr><td class="sidebar-content"> <ul><li><div style="display:inline-block; padding:0.2em 0.4em; line-height:1.2em;"><i><a href="/wiki/An_Inquiry_Concerning_the_Source_of_the_Heat_Which_Is_Excited_by_Friction" title="An Inquiry Concerning the Source of the Heat Which Is Excited by Friction">An Inquiry Concerning the<br />Source ... Friction</a></i></div></li> <li><div style="display:inline-block; padding:0.2em 0.4em; line-height:1.2em;"><i><a href="/wiki/On_the_Equilibrium_of_Heterogeneous_Substances" title="On the Equilibrium of Heterogeneous Substances">On the Equilibrium of<br />Heterogeneous Substances</a></i></div></li> <li><div style="display:inline-block; padding:0.2em 0.4em; line-height:1.2em;"><i><a href="/wiki/Reflections_on_the_Motive_Power_of_Fire" title="Reflections on the Motive Power of Fire">Reflections on the<br />Motive Power of Fire</a></i></div></li></ul></td> </tr><tr><th class="sidebar-heading" style="background:#eaeaff;font-style:italic;"> Timelines</th></tr><tr><td class="sidebar-content"> <div class="hlist"> <ul><li><a href="/wiki/Timeline_of_thermodynamics" title="Timeline of thermodynamics">Thermodynamics</a></li> <li><a href="/wiki/Timeline_of_heat_engine_technology" title="Timeline of heat engine technology">Heat engines</a></li></ul> </div></td> </tr><tr><th class="sidebar-heading" style="background:#eaeaff;font-style:italic;"> <div class="hlist"><ul><li>Art</li><li>Education</li></ul></div></th></tr><tr><td class="sidebar-content"> <ul><li><a href="/wiki/Maxwell%27s_thermodynamic_surface" title="Maxwell's thermodynamic surface">Maxwell's thermodynamic surface</a></li> <li><a href="/wiki/Entropy_(energy_dispersal)" title="Entropy (energy dispersal)">Entropy as energy dispersal</a></li></ul></td> </tr></tbody></table></div></div></td> </tr><tr><td class="sidebar-content"> <div class="sidebar-list mw-collapsible mw-collapsed"><div class="sidebar-list-title" style="background:#ddf;text-align:center;;color: var(--color-base)">Scientists</div><div class="sidebar-list-content mw-collapsible-content"><div class="hlist"> <ul><li><a href="/wiki/Daniel_Bernoulli" title="Daniel Bernoulli">Bernoulli</a></li> <li><a href="/wiki/Ludwig_Boltzmann" title="Ludwig Boltzmann">Boltzmann</a></li> <li><a href="/wiki/Percy_Williams_Bridgman" title="Percy Williams Bridgman">Bridgman</a></li> <li><a href="/wiki/Constantin_Carath%C3%A9odory" title="Constantin Carathéodory">Carathéodory</a></li> <li><a href="/wiki/Nicolas_L%C3%A9onard_Sadi_Carnot" title="Nicolas Léonard Sadi Carnot">Carnot</a></li> <li><a href="/wiki/Beno%C3%AEt_Paul_%C3%89mile_Clapeyron" class="mw-redirect" title="Benoît Paul Émile Clapeyron">Clapeyron</a></li> <li><a href="/wiki/Rudolf_Clausius" title="Rudolf Clausius">Clausius</a></li> <li><a href="/wiki/Th%C3%A9ophile_de_Donder" title="Théophile de Donder">de Donder</a></li> <li><a href="/wiki/Pierre_Duhem" title="Pierre Duhem">Duhem</a></li> <li><a href="/wiki/Josiah_Willard_Gibbs" title="Josiah Willard Gibbs">Gibbs</a></li> <li><a href="/wiki/Hermann_von_Helmholtz" title="Hermann von Helmholtz">von Helmholtz</a></li> <li><a href="/wiki/James_Prescott_Joule" title="James Prescott Joule">Joule</a></li> <li><a href="/wiki/Lord_Kelvin" title="Lord Kelvin">Kelvin</a></li> <li><a href="/wiki/Gilbert_N._Lewis" title="Gilbert N. Lewis">Lewis</a></li> <li><a href="/wiki/Fran%C3%A7ois_Massieu" title="François Massieu">Massieu</a></li> <li><a href="/wiki/James_Clerk_Maxwell" title="James Clerk Maxwell">Maxwell</a></li> <li><a href="/wiki/Julius_von_Mayer" title="Julius von Mayer">von Mayer</a></li> <li><a href="/wiki/Walther_Nernst" title="Walther Nernst">Nernst</a></li> <li><a href="/wiki/Lars_Onsager" title="Lars Onsager">Onsager</a></li> <li><a href="/wiki/Max_Planck" title="Max Planck">Planck</a></li> <li><a href="/wiki/William_John_Macquorn_Rankine" class="mw-redirect" title="William John Macquorn Rankine">Rankine</a></li> <li><a href="/wiki/John_Smeaton" title="John Smeaton">Smeaton</a></li> <li><a href="/wiki/Georg_Ernst_Stahl" title="Georg Ernst Stahl">Stahl</a></li> <li><a href="/wiki/Peter_Tait_(physicist)" class="mw-redirect" title="Peter Tait (physicist)">Tait</a></li> <li><a href="/wiki/Benjamin_Thompson" title="Benjamin Thompson">Thompson</a></li> <li><a href="/wiki/Johannes_Diderik_van_der_Waals" title="Johannes Diderik van der Waals">van der Waals</a></li> <li><a href="/wiki/John_James_Waterston" title="John James Waterston">Waterston</a></li></ul> </div></div></div></td> </tr><tr><td class="sidebar-content"> <div class="sidebar-list mw-collapsible mw-collapsed"><div class="sidebar-list-title" style="background:#ddf;text-align:center;;color: var(--color-base)">Other</div><div class="sidebar-list-content mw-collapsible-content"> <ul><li><a href="/wiki/Nucleation" title="Nucleation">Nucleation</a></li> <li><a href="/wiki/Self-assembly" title="Self-assembly">Self-assembly</a></li> <li><a href="/wiki/Self-organization" title="Self-organization">Self-organization</a></li> <li><a href="/wiki/Order_and_disorder" title="Order and disorder">Order and disorder</a></li></ul></div></div></td> </tr><tr><td class="sidebar-below"> <ul><li><span class="noviewer" typeof="mw:File"><span title="Category"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/16px-Symbol_category_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/23px-Symbol_category_class.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/31px-Symbol_category_class.svg.png 2x" data-file-width="180" data-file-height="185" /></span></span> <a href="/wiki/Category:Thermodynamics" title="Category:Thermodynamics">Category</a></li></ul></td></tr><tr><td class="sidebar-navbar"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><style data-mw-deduplicate="TemplateStyles:r1239400231">.mw-parser-output .navbar{display:inline;font-size:88%;font-weight:normal}.mw-parser-output .navbar-collapse{float:left;text-align:left}.mw-parser-output .navbar-boxtext{word-spacing:0}.mw-parser-output .navbar ul{display:inline-block;white-space:nowrap;line-height:inherit}.mw-parser-output .navbar-brackets::before{margin-right:-0.125em;content:"[ "}.mw-parser-output .navbar-brackets::after{margin-left:-0.125em;content:" ]"}.mw-parser-output .navbar li{word-spacing:-0.125em}.mw-parser-output .navbar a>span,.mw-parser-output .navbar a>abbr{text-decoration:inherit}.mw-parser-output .navbar-mini abbr{font-variant:small-caps;border-bottom:none;text-decoration:none;cursor:inherit}.mw-parser-output .navbar-ct-full{font-size:114%;margin:0 7em}.mw-parser-output .navbar-ct-mini{font-size:114%;margin:0 4em}html.skin-theme-clientpref-night .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}@media(prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}}@media print{.mw-parser-output .navbar{display:none!important}}</style><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Thermodynamics_sidebar" title="Template:Thermodynamics sidebar"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Thermodynamics_sidebar" title="Template talk:Thermodynamics sidebar"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Thermodynamics_sidebar" title="Special:EditPage/Template:Thermodynamics sidebar"><abbr title="Edit this template">e</abbr></a></li></ul></div></td></tr></tbody></table> <p><b>Energy</b> (from <a href="/wiki/Ancient_Greek_language" class="mw-redirect" title="Ancient Greek language">Ancient Greek</a> <i> </i><span lang="grc"><a href="https://en.wiktionary.org/wiki/%E1%BC%90%CE%BD%CE%AD%CF%81%CE%B3%CE%B5%CE%B9%CE%B1#Ancient_Greek" class="extiw" title="wikt:ἐνέργεια">ἐνέργεια</a></span><i> (<span title="Ancient Greek transliteration" lang="grc-Latn"><i>enérgeia</i></span>)</i> 'activity') is the <a href="/wiki/Physical_quantity" title="Physical quantity">quantitative</a> <a href="/wiki/Physical_property" title="Physical property">property</a> that is <a href="#Energy_transfer">transferred</a> to a <a href="/wiki/Physical_body" class="mw-redirect" title="Physical body">body</a> or to a <a href="/wiki/Physical_system" title="Physical system">physical system</a>, recognizable in the performance of <a href="/wiki/Work_(thermodynamics)" title="Work (thermodynamics)">work</a> and in the form of <a href="/wiki/Heat" title="Heat">heat</a> and <a href="/wiki/Light" title="Light">light</a>. Energy is a <a href="/wiki/Conservation_law" title="Conservation law">conserved quantity</a>—the law of <a href="/wiki/Conservation_of_energy" title="Conservation of energy">conservation of energy</a> states that energy can be <a href="/wiki/Energy_transformation" title="Energy transformation">converted</a> in form, but not created or destroyed; <a href="/wiki/Matter" title="Matter">matter</a> and energy may also be converted to one another. The unit of <a href="/wiki/Measurement" title="Measurement">measurement</a> for energy in the <a href="/wiki/International_System_of_Units" title="International System of Units">International System of Units</a> (SI) is the <a href="/wiki/Joule" title="Joule">joule</a> (J). </p><p>Forms of energy include the <a href="/wiki/Kinetic_energy" title="Kinetic energy">kinetic energy</a> of a moving object, the <a href="/wiki/Potential_energy" title="Potential energy">potential energy</a> stored by an object (for instance due to its position in a <a href="/wiki/Classical_field_theory" title="Classical field theory">field</a>), the <a href="/wiki/Elastic_energy" title="Elastic energy">elastic energy</a> stored in a solid object, <a href="/wiki/Chemical_energy" title="Chemical energy">chemical energy</a> associated with <a href="/wiki/Chemical_reaction" title="Chemical reaction">chemical reactions</a>, the <a href="/wiki/Radiant_energy" title="Radiant energy">radiant energy</a> carried by <a href="/wiki/Electromagnetic_radiation" title="Electromagnetic radiation">electromagnetic radiation</a>, the <a href="/wiki/Internal_energy" title="Internal energy">internal energy</a> contained within a <a href="/wiki/Thermodynamic_system" title="Thermodynamic system">thermodynamic system</a>, and <a href="/wiki/Rest_energy" class="mw-redirect" title="Rest energy">rest energy</a> associated with an object's <a href="/wiki/Rest_mass" class="mw-redirect" title="Rest mass">rest mass</a>. </p><p>All <a href="/wiki/Life" title="Life">living organisms</a> constantly take in and release energy. The Earth's <a href="/wiki/Climate" title="Climate">climate</a> and <a href="/wiki/Ecosystem" title="Ecosystem">ecosystems</a> processes are driven primarily by <a href="/wiki/Solar_irradiance" title="Solar irradiance">radiant energy from the sun</a>.<sup id="cite_ref-1" class="reference"><a href="#cite_note-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> The <a href="/wiki/Energy_industry" title="Energy industry">energy industry</a> provides the energy required for human civilization to function, which it obtains from <a href="/wiki/Energy_development" title="Energy development">energy resources</a> such as <a href="/wiki/Fossil_fuel" title="Fossil fuel">fossil fuels</a>, <a href="/wiki/Nuclear_fuel" title="Nuclear fuel">nuclear fuel</a>, and <a href="/wiki/Renewable_energy" title="Renewable energy">renewable energy</a>. </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Forms">Forms</h2></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Lightning_over_Oradea_Romania_zoom.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/2/23/Lightning_over_Oradea_Romania_zoom.jpg/220px-Lightning_over_Oradea_Romania_zoom.jpg" decoding="async" width="220" height="144" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/2/23/Lightning_over_Oradea_Romania_zoom.jpg/330px-Lightning_over_Oradea_Romania_zoom.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/2/23/Lightning_over_Oradea_Romania_zoom.jpg/440px-Lightning_over_Oradea_Romania_zoom.jpg 2x" data-file-width="1468" data-file-height="964" /></a><figcaption>In a typical <a href="/wiki/Lightning" title="Lightning">lightning</a> strike, 500 <a href="/wiki/Megajoule" class="mw-redirect" title="Megajoule">megajoules</a> of <a href="/wiki/Electric_potential_energy" title="Electric potential energy">electric potential energy</a> is converted into the same amount of energy in other forms, mostly <a href="/wiki/Light_energy" class="mw-redirect" title="Light energy">light energy</a>, <a href="/wiki/Sound_energy" title="Sound energy">sound energy</a> and <a href="/wiki/Thermal_energy" title="Thermal energy">thermal energy</a>.</figcaption></figure> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Hot_metalwork.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/a/a9/Hot_metalwork.jpg/220px-Hot_metalwork.jpg" decoding="async" width="220" height="160" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/a/a9/Hot_metalwork.jpg/330px-Hot_metalwork.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/a/a9/Hot_metalwork.jpg/440px-Hot_metalwork.jpg 2x" data-file-width="1600" data-file-height="1163" /></a><figcaption><a href="/wiki/Thermal_energy" title="Thermal energy">Thermal energy</a> is energy of microscopic constituents of matter, which may include both <a href="/wiki/Kinetic_energy" title="Kinetic energy">kinetic</a> and <a href="/wiki/Potential_energy" title="Potential energy">potential energy</a>.</figcaption></figure> <p>The total energy of a <a href="/wiki/System" title="System">system</a> can be subdivided and classified into <a href="/wiki/Potential_energy" title="Potential energy">potential energy</a>, <a href="/wiki/Kinetic_energy" title="Kinetic energy">kinetic energy</a>, or combinations of the two in various ways. Kinetic energy is determined by the <a href="/wiki/Motion_(physics)" class="mw-redirect" title="Motion (physics)">movement</a> of an object – or the <a href="/wiki/Statistical_mechanics" title="Statistical mechanics">composite motion</a> of the object's components – while <a href="/wiki/Potential_energy" title="Potential energy">potential energy</a> reflects the potential of an object to have motion, generally being based upon the object's position within a <a href="/wiki/Field_(physics)" title="Field (physics)">field</a> or what is stored within the field itself.<sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> </p><p>While these two categories are sufficient to describe all forms of energy, it is often convenient to refer to particular combinations of potential and kinetic energy as its own form. For example, the sum of translational and <a href="/wiki/Rotational_energy" title="Rotational energy">rotational</a> kinetic and potential energy within a system is referred to as <a href="/wiki/Mechanical_energy" title="Mechanical energy">mechanical energy</a>, whereas nuclear energy refers to the combined potentials within an atomic nucleus from either the <a href="/wiki/Nuclear_force" title="Nuclear force">nuclear force</a> or the <a href="/wiki/Weak_force" class="mw-redirect" title="Weak force">weak force</a>, among other examples.<sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> </p> <table class="wikitable plainrowheaders"> <caption>Some forms of energy (that an object or system can have as a measurable property) </caption> <tbody><tr> <th scope="col">Type of energy </th> <th scope="col">Description </th></tr> <tr> <th scope="row"><a href="/wiki/Mechanical_energy" title="Mechanical energy">Mechanical</a> </th> <td>the sum of <a href="/wiki/Macroscopic" class="mw-redirect" title="Macroscopic">macroscopic</a> translational and rotational kinetic and potential energies </td></tr> <tr> <th scope="row"><a href="/wiki/Electrical_energy" title="Electrical energy">Electric</a> </th> <td>potential energy due to or stored in electric fields </td></tr> <tr> <th scope="row"><a href="/wiki/Magnetic_energy" title="Magnetic energy">Magnetic</a> </th> <td>potential energy due to or stored in magnetic fields </td></tr> <tr> <th scope="row"><a href="/wiki/Gravitational_energy" title="Gravitational energy">Gravitational</a> </th> <td>potential energy due to or stored in gravitational fields </td></tr> <tr> <th scope="row"><a href="/wiki/Chemical_energy" title="Chemical energy">Chemical</a> </th> <td>potential energy due to chemical bonds </td></tr> <tr> <th scope="row"><a href="/wiki/Ionization_energy" title="Ionization energy">Ionization</a> </th> <td>potential energy that <a href="/wiki/Binding_energy" title="Binding energy">binds</a> an electron to its atom or molecule </td></tr> <tr> <th scope="row"><a href="/wiki/Nuclear_binding_energy" title="Nuclear binding energy">Nuclear</a> </th> <td>potential energy that <a href="/wiki/Binding_energy" title="Binding energy">binds</a> <a href="/wiki/Nucleons" class="mw-redirect" title="Nucleons">nucleons</a> to form the <a href="/wiki/Atomic_nucleus" title="Atomic nucleus">atomic nucleus</a> (and nuclear reactions) </td></tr> <tr> <th scope="row"><a href="/wiki/Quantum_chromodynamics_binding_energy" title="Quantum chromodynamics binding energy">Chromodynamic</a> </th> <td>potential energy that <a href="/wiki/Binding_energy" title="Binding energy">binds</a> <a href="/wiki/Quark" title="Quark">quarks</a> to form <a href="/wiki/Hadron" title="Hadron">hadrons</a> </td></tr> <tr> <th scope="row"><a href="/wiki/Elastic_energy" title="Elastic energy">Elastic</a> </th> <td>potential energy due to the deformation of a material (or its container) exhibiting a restorative force as it returns to its original shape </td></tr> <tr> <th scope="row"><a href="/wiki/Mechanical_wave" title="Mechanical wave">Mechanical wave</a> </th> <td>kinetic and potential energy in an elastic material due to a propagating <a href="/wiki/Oscillation" title="Oscillation">oscillation</a> of matter </td></tr> <tr> <th scope="row"><a href="/wiki/Sound_energy" title="Sound energy">Sound wave</a> </th> <td>kinetic and potential energy in a material due to a sound propagated wave (a particular type of mechanical wave) </td></tr> <tr> <th scope="row"><a href="/wiki/Radiant_energy" title="Radiant energy">Radiant</a> </th> <td><a href="/wiki/Photon_energy" title="Photon energy">potential energy</a> stored in the fields of waves propagated by <a href="/wiki/Electromagnetic_radiation" title="Electromagnetic radiation">electromagnetic radiation</a>, including <a href="/wiki/Light" title="Light">light</a> </td></tr> <tr> <th scope="row"><a href="/wiki/Rest_energy" class="mw-redirect" title="Rest energy">Rest</a> </th> <td>potential energy <a href="/wiki/E%3Dmc%C2%B2" class="mw-redirect" title="E=mc²">due to</a> an object's <a href="/wiki/Intrinsic_mass" class="mw-redirect" title="Intrinsic mass">rest mass</a> </td></tr> <tr> <th scope="row"><a href="/wiki/Heat" title="Heat">Thermal</a> </th> <td>kinetic energy of the <a href="/wiki/Microscopic" class="mw-redirect" title="Microscopic">microscopic</a> motion of particles, a kind of disordered equivalent of mechanical energy </td></tr> </tbody></table> <div class="mw-heading mw-heading2"><h2 id="History">History</h2></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main articles: <a href="/wiki/History_of_energy" title="History of energy">History of energy</a> and <a href="/wiki/Timeline_of_thermodynamics,_statistical_mechanics,_and_random_processes" class="mw-redirect" title="Timeline of thermodynamics, statistical mechanics, and random processes">timeline of thermodynamics, statistical mechanics, and random processes</a></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Thomas_Young_(scientist).jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/9/9f/Thomas_Young_%28scientist%29.jpg/170px-Thomas_Young_%28scientist%29.jpg" decoding="async" width="170" height="215" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/9/9f/Thomas_Young_%28scientist%29.jpg/255px-Thomas_Young_%28scientist%29.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/9/9f/Thomas_Young_%28scientist%29.jpg/340px-Thomas_Young_%28scientist%29.jpg 2x" data-file-width="898" data-file-height="1138" /></a><figcaption><a href="/wiki/Thomas_Young_(scientist)" title="Thomas Young (scientist)">Thomas Young</a>, the first person to use the term "energy" in the modern sense</figcaption></figure> <p>The word <i>energy</i> derives from the <a href="/wiki/Ancient_Greek_language" class="mw-redirect" title="Ancient Greek language">Ancient Greek</a>: <span lang="grc">ἐνέργεια</span>, <small><a href="/wiki/Romanization_of_Ancient_Greek" class="mw-redirect" title="Romanization of Ancient Greek">romanized</a>: </small><span title="Ancient Greek-language romanization"><i lang="grc-Latn"><a href="/wiki/Energeia" class="mw-redirect" title="Energeia">energeia</a></i></span>, <small><a href="/wiki/Literal_translation" title="Literal translation">lit.</a> </small>'activity, operation',<sup id="cite_ref-4" class="reference"><a href="#cite_note-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> which possibly appears for the first time in the work of <a href="/wiki/Aristotle" title="Aristotle">Aristotle</a> in the 4th century BC. In contrast to the modern definition, energeia was a qualitative philosophical concept, broad enough to include ideas such as happiness and pleasure. </p><p>In the late 17th century, <a href="/wiki/Gottfried_Leibniz" class="mw-redirect" title="Gottfried Leibniz">Gottfried Leibniz</a> proposed the idea of the <a href="/wiki/Latin_language" class="mw-redirect" title="Latin language">Latin</a>: <i lang="la"><a href="/wiki/Vis_viva" title="Vis viva">vis viva</a></i>, or living force, which defined as the product of the mass of an object and its velocity squared; he believed that total <i>vis viva</i> was conserved. To account for slowing due to friction, Leibniz theorized that thermal energy consisted of the motions of the constituent parts of matter, although it would be more than a century until this was generally accepted. The modern analog of this property, <a href="/wiki/Kinetic_energy" title="Kinetic energy">kinetic energy</a>, differs from <i>vis viva</i> only by a factor of two. Writing in the early 18th century, <a href="/wiki/%C3%89milie_du_Ch%C3%A2telet" title="Émilie du Châtelet">Émilie du Châtelet</a> proposed the concept of <a href="/wiki/Conservation_of_energy" title="Conservation of energy">conservation of energy</a> in the marginalia of her French language translation of Newton's <i><a href="/wiki/Philosophi%C3%A6_Naturalis_Principia_Mathematica" title="Philosophiæ Naturalis Principia Mathematica">Principia Mathematica</a></i>, which represented the first formulation of a conserved measurable quantity that was distinct from <a href="/wiki/Momentum" title="Momentum">momentum</a>, and which would later be called "energy". </p><p>In 1807, <a href="/wiki/Thomas_Young_(scientist)" title="Thomas Young (scientist)">Thomas Young</a> was possibly the first to use the term "energy" instead of <i>vis viva</i>, in its modern sense.<sup id="cite_ref-5" class="reference"><a href="#cite_note-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup> <a href="/wiki/Gustave-Gaspard_Coriolis" class="mw-redirect" title="Gustave-Gaspard Coriolis">Gustave-Gaspard Coriolis</a> described "<a href="/wiki/Kinetic_energy" title="Kinetic energy">kinetic energy</a>" in 1829 in its modern sense, and in 1853, <a href="/wiki/William_John_Macquorn_Rankine" class="mw-redirect" title="William John Macquorn Rankine">William Rankine</a> coined the term "<a href="/wiki/Potential_energy" title="Potential energy">potential energy</a>". The law of <a href="/wiki/Conservation_of_energy" title="Conservation of energy">conservation of energy</a> was also first postulated in the early 19th century, and applies to any <a href="/wiki/Isolated_system" title="Isolated system">isolated system</a>. It was argued for some years whether heat was a physical substance, dubbed the <a href="/wiki/Caloric_theory" title="Caloric theory">caloric</a>, or merely a physical quantity, such as <a href="/wiki/Momentum" title="Momentum">momentum</a>. In 1845 <a href="/wiki/James_Prescott_Joule" title="James Prescott Joule">James Prescott Joule</a> discovered the link between mechanical work and the generation of heat. </p><p>These developments led to the theory of conservation of energy, formalized largely by William Thomson (<a href="/wiki/Lord_Kelvin" title="Lord Kelvin">Lord Kelvin</a>) as the field of <a href="/wiki/Thermodynamics" title="Thermodynamics">thermodynamics</a>. Thermodynamics aided the rapid development of explanations of chemical processes by <a href="/wiki/Rudolf_Clausius" title="Rudolf Clausius">Rudolf Clausius</a>, <a href="/wiki/Josiah_Willard_Gibbs" title="Josiah Willard Gibbs">Josiah Willard Gibbs</a>, and <a href="/wiki/Walther_Nernst" title="Walther Nernst">Walther Nernst</a>. It also led to a mathematical formulation of the concept of <a href="/wiki/Entropy" title="Entropy">entropy</a> by Clausius and to the introduction of laws of <a href="/wiki/Radiant_energy" title="Radiant energy">radiant energy</a> by <a href="/wiki/Jo%C5%BEef_Stefan" class="mw-redirect" title="Jožef Stefan">Jožef Stefan</a>. According to <a href="/wiki/Noether%27s_theorem" title="Noether's theorem">Noether's theorem</a>, the conservation of energy is a consequence of the fact that the laws of physics do not change over time.<sup id="cite_ref-jphysics_6-0" class="reference"><a href="#cite_note-jphysics-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup> Thus, since 1918, theorists have understood that the law of <a href="/wiki/Conservation_of_energy" title="Conservation of energy">conservation of energy</a> is the direct mathematical consequence of the <a href="/wiki/Translational_symmetry" title="Translational symmetry">translational symmetry</a> of the quantity <a href="/wiki/Conjugate_variables" title="Conjugate variables">conjugate</a> to energy, namely time. </p> <div class="mw-heading mw-heading2"><h2 id="Units_of_measure">Units of measure</h2></div> <figure class="mw-default-size mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:Joule%27s_Apparatus_(Harper%27s_Scan).png" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/c/c3/Joule%27s_Apparatus_%28Harper%27s_Scan%29.png/220px-Joule%27s_Apparatus_%28Harper%27s_Scan%29.png" decoding="async" width="220" height="181" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/c/c3/Joule%27s_Apparatus_%28Harper%27s_Scan%29.png/330px-Joule%27s_Apparatus_%28Harper%27s_Scan%29.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/c/c3/Joule%27s_Apparatus_%28Harper%27s_Scan%29.png/440px-Joule%27s_Apparatus_%28Harper%27s_Scan%29.png 2x" data-file-width="1684" data-file-height="1387" /></a><figcaption>Joule's apparatus for measuring the mechanical equivalent of heat. A descending weight attached to a string causes a paddle immersed in water to rotate.</figcaption></figure> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Units_of_energy" title="Units of energy">Units of energy</a></div> <p>In the <a href="/wiki/International_System_of_Units" title="International System of Units">International System of Units</a> (SI), the unit of energy is the <a href="/wiki/Joule" title="Joule">joule</a>. It is a <a href="/wiki/SI_derived_unit" title="SI derived unit">derived unit</a> that is equal to the energy expended, or <a href="/wiki/Work_(physics)" title="Work (physics)">work</a> done, in applying a force of one <a href="/wiki/Newton_(unit)" title="Newton (unit)">newton</a> through a distance of one metre. However energy can also be expressed in many other units not part of the SI, such as <a href="/wiki/Erg" title="Erg">ergs</a>, <a href="/wiki/Calorie" title="Calorie">calories</a>, <a href="/wiki/British_thermal_unit" title="British thermal unit">British thermal units</a>, <a href="/wiki/Kilowatt-hour" title="Kilowatt-hour">kilowatt-hours</a> and <a href="/wiki/Kilocalorie" class="mw-redirect" title="Kilocalorie">kilocalories</a>, which require a conversion factor when expressed in SI units. </p><p>The SI unit of <a href="/wiki/Power_(physics)" title="Power (physics)">power</a>, defined as energy per unit of time, is the <a href="/wiki/Watt" title="Watt">watt</a>, which is a joule per second. Thus, one joule is one watt-second, and 3600 joules equal one watt-hour. The <a href="/wiki/Centimetre_gram_second_system_of_units" class="mw-redirect" title="Centimetre gram second system of units">CGS</a> energy unit is the <a href="/wiki/Erg" title="Erg">erg</a> and the <a href="/wiki/Imperial_and_US_customary_measurement_systems" title="Imperial and US customary measurement systems">imperial and US customary</a> unit is the <a href="/wiki/Foot_pound" class="mw-redirect" title="Foot pound">foot pound</a>. Other energy units such as the <a href="/wiki/Electronvolt" title="Electronvolt">electronvolt</a>, <a href="/wiki/Food_calorie" class="mw-redirect" title="Food calorie">food calorie</a> or thermodynamic <a href="/wiki/Kilocalorie" class="mw-redirect" title="Kilocalorie">kcal</a> (based on the temperature change of water in a heating process), and <a href="/wiki/British_thermal_unit" title="British thermal unit">BTU</a> are used in specific areas of science and commerce. </p><p>In 1843, <a href="/wiki/French_people" title="French people">French</a> <a href="/wiki/Physicist" title="Physicist">physicist</a> <a href="/wiki/James_Prescott_Joule" title="James Prescott Joule">James Prescott Joule</a>, <a href="/wiki/Namesake" title="Namesake">namesake</a> of the unit of measure, discovered that the <a href="/wiki/Gravity" title="Gravity">gravitational</a> <a href="/wiki/Potential_energy" title="Potential energy">potential energy</a> lost by a descending weight attached via a string was equal to the <a href="/wiki/Internal_energy" title="Internal energy">internal energy</a> gained by the water through <a href="/wiki/Friction" title="Friction">friction</a> with the paddle. </p> <div class="mw-heading mw-heading2"><h2 id="Scientific_use">Scientific use</h2></div> <div class="mw-heading mw-heading3"><h3 id="Classical_mechanics">Classical mechanics</h3></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1126788409"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1246091330"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1126788409"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1126788409"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><table class="sidebar sidebar-collapse nomobile nowraplinks"><tbody><tr><td class="sidebar-pretitle">Part of a series on</td></tr><tr><th class="sidebar-title-with-pretitle" style="padding-left:0.9em;padding-right:0.9em;"><a href="/wiki/Classical_mechanics" title="Classical mechanics">Classical mechanics</a></th></tr><tr><td class="sidebar-image"><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\textbf {F}}={\frac {d\mathbf {p} }{dt}}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mrow class="MJX-TeXAtom-ORD"> <mrow class="MJX-TeXAtom-ORD"> <mtext mathvariant="bold">F</mtext> </mrow> </mrow> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mrow> <mi>d</mi> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="bold">p</mi> </mrow> </mrow> <mrow> <mi>d</mi> <mi>t</mi> </mrow> </mfrac> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle {\textbf {F}}={\frac {d\mathbf {p} }{dt}}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/c2ad0a6d6780c3abc5247abd82bd8a2249d56ff3" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -2.005ex; width:8.318ex; height:5.509ex;" alt="{\displaystyle {\textbf {F}}={\frac {d\mathbf {p} }{dt}}}"></span><div class="sidebar-caption" style="font-size:90%;padding:0.6em 0;font-style:italic;"><a href="/wiki/Second_law_of_motion" class="mw-redirect" title="Second law of motion">Second law of motion</a></div></td></tr><tr><th class="sidebar-heading" style="font-weight: bold; display:block;margin-bottom:1.0em;"> <div class="hlist"> <ul><li><a href="/wiki/History_of_classical_mechanics" title="History of classical mechanics">History</a></li> <li><a href="/wiki/Timeline_of_classical_mechanics" title="Timeline of classical mechanics">Timeline</a></li> <li><a href="/wiki/List_of_textbooks_on_classical_mechanics_and_quantum_mechanics" title="List of textbooks on classical mechanics and quantum mechanics">Textbooks</a></li></ul> </div></th></tr><tr><td class="sidebar-content"> <div class="sidebar-list mw-collapsible mw-collapsed"><div class="sidebar-list-title" style="border-bottom: 1px solid black;text-align:center;;color: var(--color-base)">Branches</div><div class="sidebar-list-content mw-collapsible-content plainlist" style="padding-top:0.35em;"><div class="hlist"> <ul><li><a href="/wiki/Applied_mechanics" title="Applied mechanics">Applied</a></li> <li><a href="/wiki/Celestial_mechanics" title="Celestial mechanics">Celestial</a></li> <li><a href="/wiki/Continuum_mechanics" title="Continuum mechanics">Continuum</a></li> <li><a href="/wiki/Analytical_dynamics" class="mw-redirect" title="Analytical dynamics">Dynamics</a></li> <li><a href="/wiki/Classical_field_theory" title="Classical field theory">Field theory</a></li> <li><a href="/wiki/Kinematics" title="Kinematics">Kinematics</a></li> <li><a href="/wiki/Kinetics_(physics)" title="Kinetics (physics)">Kinetics</a></li> <li><a href="/wiki/Statics" title="Statics">Statics</a></li> <li><a href="/wiki/Statistical_mechanics" title="Statistical mechanics">Statistical mechanics</a></li></ul> </div></div></div></td> </tr><tr><td class="sidebar-content"> <div class="sidebar-list mw-collapsible mw-collapsed"><div class="sidebar-list-title" style="border-bottom: 1px solid black;text-align:center;;color: var(--color-base)">Fundamentals</div><div class="sidebar-list-content mw-collapsible-content plainlist" style="padding-top:0.35em;"><div class="hlist"> <ul><li><a href="/wiki/Acceleration" title="Acceleration">Acceleration</a></li> <li><a href="/wiki/Angular_momentum" title="Angular momentum">Angular momentum</a></li> <li><a href="/wiki/Couple_(mechanics)" title="Couple (mechanics)">Couple</a></li> <li><a href="/wiki/D%27Alembert%27s_principle" title="D'Alembert's principle">D'Alembert's principle</a></li> <li><a class="mw-selflink selflink">Energy</a> <ul><li><a href="/wiki/Kinetic_energy#Newtonian_kinetic_energy" title="Kinetic energy">kinetic</a></li> <li><a href="/wiki/Potential_energy" title="Potential energy">potential</a></li></ul></li> <li><a href="/wiki/Force" title="Force">Force</a></li> <li><a href="/wiki/Frame_of_reference" title="Frame of reference">Frame of reference</a></li> <li><a href="/wiki/Inertial_frame_of_reference" title="Inertial frame of reference">Inertial frame of reference</a></li> <li><a href="/wiki/Impulse_(physics)" title="Impulse (physics)">Impulse</a></li> <li><span class="nowrap"><a href="/wiki/Inertia" title="Inertia">Inertia</a> / <a href="/wiki/Moment_of_inertia" title="Moment of inertia">Moment of inertia</a></span></li> <li><a href="/wiki/Mass" title="Mass">Mass</a></li> <li><br /><a href="/wiki/Mechanical_power_(physics)" class="mw-redirect" title="Mechanical power (physics)">Mechanical power</a></li> <li><a href="/wiki/Work_(physics)" title="Work (physics)">Mechanical work</a></li> <li><br /><a href="/wiki/Moment_(physics)" title="Moment (physics)">Moment</a></li> <li><a href="/wiki/Momentum" title="Momentum">Momentum</a></li> <li><a href="/wiki/Space" title="Space">Space</a></li> <li><a href="/wiki/Speed" title="Speed">Speed</a></li> <li><a href="/wiki/Time" title="Time">Time</a></li> <li><a href="/wiki/Torque" title="Torque">Torque</a></li> <li><a href="/wiki/Velocity" title="Velocity">Velocity</a></li> <li><a href="/wiki/Virtual_work" title="Virtual work">Virtual work</a></li></ul> </div></div></div></td> </tr><tr><td class="sidebar-content"> <div class="sidebar-list mw-collapsible mw-collapsed"><div class="sidebar-list-title" style="border-bottom: 1px solid black;text-align:center;;color: var(--color-base)">Formulations</div><div class="sidebar-list-content mw-collapsible-content plainlist" style="padding-top:0.35em;"> <ul><li><div style="display: inline-block; line-height: 1.2em; padding: .1em 0;"><b><a href="/wiki/Newton%27s_laws_of_motion" title="Newton's laws of motion">Newton's laws of motion</a></b></div></li> <li><div style="display: inline-block; line-height: 1.2em; padding: .1em 0;"><b><a href="/wiki/Analytical_mechanics" title="Analytical mechanics">Analytical mechanics</a></b> <div class="plainlist"><ul><li><a href="/wiki/Lagrangian_mechanics" title="Lagrangian mechanics">Lagrangian mechanics</a></li><li><a href="/wiki/Hamiltonian_mechanics" title="Hamiltonian mechanics">Hamiltonian mechanics</a></li><li><a href="/wiki/Routhian_mechanics" title="Routhian mechanics">Routhian mechanics</a></li><li><a href="/wiki/Hamilton%E2%80%93Jacobi_equation" title="Hamilton–Jacobi equation">Hamilton–Jacobi equation</a></li><li><a href="/wiki/Appell%27s_equation_of_motion" title="Appell's equation of motion">Appell's equation of motion</a></li><li><a href="/wiki/Koopman%E2%80%93von_Neumann_classical_mechanics" title="Koopman–von Neumann classical mechanics">Koopman–von Neumann mechanics</a></li></ul></div></div></li></ul></div></div></td> </tr><tr><td class="sidebar-content"> <div class="sidebar-list mw-collapsible mw-collapsed"><div class="sidebar-list-title" style="border-bottom: 1px solid black;text-align:center;;color: var(--color-base)">Core topics</div><div class="sidebar-list-content mw-collapsible-content plainlist" style="padding-top:0.35em;"><div class="hlist"> <ul><li><a href="/wiki/Damping" title="Damping">Damping</a></li> <li><a href="/wiki/Displacement_(geometry)" title="Displacement (geometry)">Displacement</a></li> <li><a href="/wiki/Equations_of_motion" title="Equations of motion">Equations of motion</a></li> <li><a href="/wiki/Euler%27s_laws_of_motion" title="Euler's laws of motion"><span class="wrap">Euler's laws of motion</span></a></li> <li><a href="/wiki/Fictitious_force" title="Fictitious force">Fictitious force</a></li> <li><a href="/wiki/Friction" title="Friction">Friction</a></li> <li><a href="/wiki/Harmonic_oscillator" title="Harmonic oscillator">Harmonic oscillator</a></li></ul> </div> <ul><li><span class="nowrap"><a href="/wiki/Inertial_frame_of_reference" title="Inertial frame of reference">Inertial</a> / <a href="/wiki/Non-inertial_reference_frame" title="Non-inertial reference frame">Non-inertial reference frame</a></span></li></ul> <div class="hlist"> <ul><li><a href="/wiki/Motion" title="Motion">Motion</a> (<a href="/wiki/Linear_motion" title="Linear motion">linear</a>)</li> <li><a href="/wiki/Newton%27s_law_of_universal_gravitation" title="Newton's law of universal gravitation"><span class="wrap">Newton's law of universal gravitation</span></a></li> <li><a href="/wiki/Newton%27s_laws_of_motion" title="Newton's laws of motion">Newton's laws of motion</a></li> <li><a href="/wiki/Relative_velocity" title="Relative velocity">Relative velocity</a></li> <li><a href="/wiki/Rigid_body" title="Rigid body">Rigid body</a> <ul><li><a href="/wiki/Rigid_body_dynamics" title="Rigid body dynamics">dynamics</a></li> <li><a href="/wiki/Euler%27s_equations_(rigid_body_dynamics)" title="Euler's equations (rigid body dynamics)">Euler's equations</a></li></ul></li> <li><a href="/wiki/Simple_harmonic_motion" title="Simple harmonic motion">Simple harmonic motion</a></li> <li><a href="/wiki/Vibration" title="Vibration">Vibration</a></li></ul> </div></div></div></td> </tr><tr><td class="sidebar-content"> <div class="sidebar-list mw-collapsible mw-collapsed"><div class="sidebar-list-title" style="border-bottom: 1px solid black;text-align:center;;color: var(--color-base)"><a href="/wiki/Rotation_around_a_fixed_axis" title="Rotation around a fixed axis">Rotation</a></div><div class="sidebar-list-content mw-collapsible-content plainlist" style="padding-top:0.35em;"><div class="hlist"> <ul><li><a href="/wiki/Circular_motion" title="Circular motion">Circular motion</a></li> <li><a href="/wiki/Rotating_reference_frame" title="Rotating reference frame">Rotating reference frame</a></li> <li><a href="/wiki/Centripetal_force" title="Centripetal force">Centripetal force</a></li> <li><a href="/wiki/Centrifugal_force" title="Centrifugal force">Centrifugal force</a> <ul><li><a href="/wiki/Reactive_centrifugal_force" title="Reactive centrifugal force">reactive</a></li></ul></li> <li><a href="/wiki/Coriolis_force" title="Coriolis force">Coriolis force</a></li> <li><a href="/wiki/Pendulum_(mechanics)" title="Pendulum (mechanics)">Pendulum</a></li> <li><a href="/wiki/Tangential_speed" title="Tangential speed">Tangential speed</a></li> <li><a href="/wiki/Rotational_frequency" title="Rotational frequency">Rotational frequency</a></li></ul> </div> <ul><li><a href="/wiki/Angular_acceleration" title="Angular acceleration">Angular acceleration</a> / <a href="/wiki/Angular_displacement" title="Angular displacement">displacement</a> / <a href="/wiki/Angular_frequency" title="Angular frequency">frequency</a> / <a href="/wiki/Angular_velocity" title="Angular velocity">velocity</a></li></ul></div></div></td> </tr><tr><td class="sidebar-content"> <div class="sidebar-list 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Bernoulli</a></li> <li><a href="/wiki/Leonhard_Euler" title="Leonhard Euler">Euler</a></li> <li><a href="/wiki/Jean_le_Rond_d%27Alembert" title="Jean le Rond d'Alembert">d'Alembert</a></li> <li><a href="/wiki/Alexis_Clairaut" title="Alexis Clairaut">Clairaut</a></li> <li><a href="/wiki/Joseph-Louis_Lagrange" title="Joseph-Louis Lagrange">Lagrange</a></li> <li><a href="/wiki/Pierre-Simon_Laplace" title="Pierre-Simon Laplace">Laplace</a></li> <li><a href="/wiki/Sim%C3%A9on_Denis_Poisson" title="Siméon Denis Poisson">Poisson</a></li> <li><a href="/wiki/William_Rowan_Hamilton" title="William Rowan Hamilton">Hamilton</a></li> <li><a href="/wiki/Carl_Gustav_Jacob_Jacobi" title="Carl Gustav Jacob Jacobi">Jacobi</a></li> <li><a href="/wiki/Augustin-Louis_Cauchy" title="Augustin-Louis Cauchy">Cauchy</a></li> <li><a href="/wiki/Edward_Routh" title="Edward Routh">Routh</a></li> <li><a href="/wiki/Joseph_Liouville" title="Joseph Liouville">Liouville</a></li> <li><a href="/wiki/Paul_%C3%89mile_Appell" title="Paul Émile Appell">Appell</a></li> <li><a href="/wiki/Josiah_Willard_Gibbs" title="Josiah Willard Gibbs">Gibbs</a></li> <li><a href="/wiki/Bernard_Koopman" title="Bernard Koopman">Koopman</a></li> <li><a href="/wiki/John_von_Neumann" title="John von Neumann">von Neumann</a></li></ul> </div></div></div></td> </tr><tr><td class="sidebar-below hlist" style="background-color: transparent; border-color: #A2B8BF"> <ul><li><span class="nowrap"><span class="nowrap"><span class="noviewer" typeof="mw:File"><a href="/wiki/File:Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg" class="mw-file-description"><img alt="icon" src="//upload.wikimedia.org/wikipedia/commons/thumb/6/6f/Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg/14px-Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg.png" decoding="async" width="14" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/6/6f/Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg/21px-Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/6/6f/Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg/28px-Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg.png 2x" data-file-width="530" data-file-height="600" /></a></span> </span><a href="/wiki/Portal:Physics" title="Portal:Physics">Physics portal</a></span></li> <li><span class="nowrap"><span class="noviewer" typeof="mw:File"><span title="Category"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/16px-Symbol_category_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/23px-Symbol_category_class.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/31px-Symbol_category_class.svg.png 2x" data-file-width="180" data-file-height="185" /></span></span> <a href="/wiki/Category:Classical_mechanics" title="Category:Classical mechanics">Category</a></span></li></ul></td></tr><tr><td class="sidebar-navbar"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239400231"><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Classical_mechanics" title="Template:Classical mechanics"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Classical_mechanics" title="Template talk:Classical mechanics"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Classical_mechanics" title="Special:EditPage/Template:Classical mechanics"><abbr title="Edit this template">e</abbr></a></li></ul></div></td></tr></tbody></table> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main articles: <a href="/wiki/Mechanics" title="Mechanics">Mechanics</a>, <a href="/wiki/Mechanical_work" class="mw-redirect" title="Mechanical work">Mechanical work</a>, and <a href="/wiki/Thermodynamics" title="Thermodynamics">Thermodynamics</a></div> <p>In classical mechanics, energy is a conceptually and mathematically useful property, as it is a <a href="/wiki/Conserved_quantity" title="Conserved quantity">conserved quantity</a>. Several formulations of mechanics have been developed using energy as a core concept. </p><p><a href="/wiki/Work_(physics)" title="Work (physics)">Work</a>, a function of energy, is force times distance. </p> <dl><dd><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle W=\int _{C}\mathbf {F} \cdot \mathrm {d} \mathbf {s} }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>W</mi> <mo>=</mo> <msub> <mo>∫</mo> <mrow class="MJX-TeXAtom-ORD"> <mi>C</mi> </mrow> </msub> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="bold">F</mi> </mrow> <mo>⋅</mo> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="normal">d</mi> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="bold">s</mi> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle W=\int _{C}\mathbf {F} \cdot \mathrm {d} \mathbf {s} }</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/db88166e600c5c87817f25ce9a056bc12c30338b" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -2.338ex; width:14.405ex; height:5.676ex;" alt="{\displaystyle W=\int _{C}\mathbf {F} \cdot \mathrm {d} \mathbf {s} }"></span></dd></dl> <p>This says that the work (<span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle W}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>W</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle W}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/54a9c4c547f4d6111f81946cad242b18298d70b7" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:2.435ex; height:2.176ex;" alt="{\displaystyle W}"></span>) is equal to the <a href="/wiki/Line_integral" title="Line integral">line integral</a> of the <a href="/wiki/Force" title="Force">force</a> <b>F</b> along a path <i>C</i>; for details see the <a href="/wiki/Mechanical_work" class="mw-redirect" title="Mechanical work">mechanical work</a> article. Work and thus energy is <a href="/wiki/Frame_dependent" class="mw-redirect" title="Frame dependent">frame dependent</a>. For example, consider a ball being hit by a bat. In the center-of-mass reference frame, the bat does no work on the ball. But, in the reference frame of the person swinging the bat, considerable work is done on the ball. </p><p>The total energy of a system is sometimes called the <a href="/wiki/Hamilton%27s_equations" class="mw-redirect" title="Hamilton's equations">Hamiltonian</a>, after <a href="/wiki/William_Rowan_Hamilton" title="William Rowan Hamilton">William Rowan Hamilton</a>. The classical equations of motion can be written in terms of the Hamiltonian, even for highly complex or abstract systems. These classical equations have direct analogs in nonrelativistic quantum mechanics.<sup id="cite_ref-7" class="reference"><a href="#cite_note-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup> </p><p>Another energy-related concept is called the <a href="/wiki/Lagrangian_mechanics" title="Lagrangian mechanics">Lagrangian</a>, after <a href="/wiki/Joseph-Louis_Lagrange" title="Joseph-Louis Lagrange">Joseph-Louis Lagrange</a>. This formalism is as fundamental as the Hamiltonian, and both can be used to derive the equations of motion or be derived from them. It was invented in the context of <a href="/wiki/Classical_mechanics" title="Classical mechanics">classical mechanics</a>, but is generally useful in modern physics. The Lagrangian is defined as the kinetic energy <i>minus</i> the potential energy. Usually, the Lagrange formalism is mathematically more convenient than the Hamiltonian for non-conservative systems (such as systems with friction). </p><p><a href="/wiki/Noether%27s_theorem" title="Noether's theorem">Noether's theorem</a> (1918) states that any differentiable symmetry of the action of a physical system has a corresponding conservation law. Noether's theorem has become a fundamental tool of modern theoretical physics and the calculus of variations. A generalisation of the seminal formulations on constants of motion in Lagrangian and Hamiltonian mechanics (1788 and 1833, respectively), it does not apply to systems that cannot be modeled with a Lagrangian; for example, dissipative systems with continuous symmetries need not have a corresponding conservation law. </p> <div class="mw-heading mw-heading3"><h3 id="Chemistry">Chemistry</h3></div> <p>In the context of <a href="/wiki/Chemistry#Energy" title="Chemistry">chemistry</a>, <a href="/wiki/Chemical_energy" title="Chemical energy">energy</a> is an attribute of a substance as a consequence of its atomic, molecular, or aggregate structure. Since a chemical transformation is accompanied by a change in one or more of these kinds of structure, it is usually accompanied by a decrease, and sometimes an increase, of the total energy of the substances involved. Some energy may be transferred between the surroundings and the reactants in the form of heat or light; thus the products of a reaction have sometimes more but usually less energy than the reactants. A reaction is said to be <a href="/wiki/Exothermic_process" title="Exothermic process">exothermic</a> or <a href="/wiki/Exergonic" class="mw-redirect" title="Exergonic">exergonic</a> if the final state is lower on the energy scale than the initial state; in the less common case of <a href="/wiki/Endothermic_process" title="Endothermic process">endothermic</a> reactions the situation is the reverse. </p><p><a href="/wiki/Chemical_reaction" title="Chemical reaction">Chemical reactions</a> are usually not possible unless the reactants surmount an energy barrier known as the <a href="/wiki/Activation_energy" title="Activation energy">activation energy</a>. The <i>speed</i> of a chemical reaction (at a given temperature <i>T</i>) is related to the activation energy <i>E</i> by the Boltzmann's population factor e<sup>−<i>E</i>/<i>kT</i></sup>; that is, the probability of a molecule to have energy greater than or equal to <i>E</i> at a given temperature <i>T</i>. This exponential dependence of a reaction rate on temperature is known as the <a href="/wiki/Arrhenius_equation" title="Arrhenius equation">Arrhenius equation</a>. The activation energy necessary for a chemical reaction can be provided in the form of thermal energy. </p> <div class="mw-heading mw-heading3"><h3 id="Biology">Biology</h3></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main articles: <a href="/wiki/Bioenergetics" title="Bioenergetics">Bioenergetics</a> and <a href="/wiki/Food_energy" title="Food energy">Food energy</a></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Energy_and_life.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/4/4c/Energy_and_life.svg/220px-Energy_and_life.svg.png" decoding="async" width="220" height="167" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/4/4c/Energy_and_life.svg/330px-Energy_and_life.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/4/4c/Energy_and_life.svg/440px-Energy_and_life.svg.png 2x" data-file-width="746" data-file-height="565" /></a><figcaption>Basic overview of <a href="/wiki/Bioenergetics" title="Bioenergetics">energy and human life</a></figcaption></figure> <p><span class="anchor" id="Biology"></span>In <a href="/wiki/Biology#Energy" title="Biology">biology</a>, energy is an attribute of all biological systems, from the biosphere to the smallest living organism. Within an organism it is responsible for growth and development of a biological <a href="/wiki/Cell_(biology)" title="Cell (biology)">cell</a> or <a href="/wiki/Organelle" title="Organelle">organelle</a> of a biological organism. Energy used in <a href="/wiki/Respiration_(physiology)" title="Respiration (physiology)">respiration</a> is stored in substances such as <a href="/wiki/Carbohydrate" title="Carbohydrate">carbohydrates</a> (including sugars), <a href="/wiki/Lipid" title="Lipid">lipids</a>, and <a href="/wiki/Protein" title="Protein">proteins</a> stored by <a href="/wiki/Cell_(biology)" title="Cell (biology)">cells</a>. In human terms, the <a href="/wiki/Human_equivalent" title="Human equivalent">human equivalent</a> (H-e) (Human energy conversion) indicates, for a given amount of energy expenditure, the relative quantity of energy needed for human <a href="/wiki/Metabolism" title="Metabolism">metabolism</a>, using as a standard an average human energy expenditure of 12,500 kJ per day and a <a href="/wiki/Basal_metabolic_rate" title="Basal metabolic rate">basal metabolic rate</a> of 80 watts. </p><p>For example, if our bodies run (on average) at 80 watts, then a light bulb running at 100 watts is running at 1.25 human equivalents (100 ÷ 80) i.e. 1.25 H-e. For a difficult task of only a few seconds' duration, a person can put out thousands of watts, many times the 746 watts in one official horsepower. For tasks lasting a few minutes, a fit human can generate perhaps 1,000 watts. For an activity that must be sustained for an hour, output drops to around 300; for an activity kept up all day, 150 watts is about the maximum.<sup id="cite_ref-8" class="reference"><a href="#cite_note-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup> The human equivalent assists understanding of energy flows in physical and biological systems by expressing energy units in human terms: it provides a "feel" for the use of a given amount of energy.<sup id="cite_ref-9" class="reference"><a href="#cite_note-9"><span class="cite-bracket">[</span>9<span class="cite-bracket">]</span></a></sup> </p><p>Sunlight's radiant energy is also captured by plants as <i>chemical potential energy</i> in <a href="/wiki/Photosynthesis" title="Photosynthesis">photosynthesis</a>, when carbon dioxide and water (two low-energy compounds) are converted into carbohydrates, lipids, proteins and oxygen. Release of the energy stored during photosynthesis as heat or light may be triggered suddenly by a spark in a forest fire, or it may be made available more slowly for animal or human metabolism when organic molecules are ingested and <a href="/wiki/Catabolism" title="Catabolism">catabolism</a> is triggered by <a href="/wiki/Enzyme" title="Enzyme">enzyme</a> action. </p><p>All living creatures rely on an external source of energy to be able to grow and reproduce – radiant energy from the Sun in the case of green plants and chemical energy (in some form) in the case of animals. The daily 1500–2000 <a href="/wiki/Kilocalorie" class="mw-redirect" title="Kilocalorie">Calories</a> (6–8 MJ) recommended for a human adult are taken as food molecules, mostly carbohydrates and fats, of which <a href="/wiki/Glucose" title="Glucose">glucose</a> (C<sub>6</sub>H<sub>12</sub>O<sub>6</sub>) and <a href="/wiki/Stearin" title="Stearin">stearin</a> (C<sub>57</sub>H<sub>110</sub>O<sub>6</sub>) are convenient examples. The food molecules are oxidized to <a href="/wiki/Carbon_dioxide" title="Carbon dioxide">carbon dioxide</a> and <a href="/wiki/Water_(molecule)" class="mw-redirect" title="Water (molecule)">water</a> in the <a href="/wiki/Mitochondrion" title="Mitochondrion">mitochondria</a> <span class="mwe-math-element"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\ce {C6H12O6 + 6O2 -> 6CO2 + 6H2O}}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mrow class="MJX-TeXAtom-ORD"> <msubsup> <mtext>C</mtext> <mrow class="MJX-TeXAtom-ORD"> <mn>6</mn> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mspace width="0pt" height="0pt" depth=".2em" /> </mrow> </msubsup> <msubsup> <mtext>H</mtext> <mrow class="MJX-TeXAtom-ORD"> <mn>12</mn> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mspace width="0pt" height="0pt" depth=".2em" /> </mrow> </msubsup> <msubsup> <mtext>O</mtext> <mrow class="MJX-TeXAtom-ORD"> <mn>6</mn> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mspace width="0pt" height="0pt" depth=".2em" /> </mrow> </msubsup> <mo>+</mo> <mn>6</mn> <mspace width="thinmathspace" /> <msubsup> <mtext>O</mtext> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mspace width="0pt" height="0pt" depth=".2em" /> </mrow> </msubsup> <mo stretchy="false">⟶</mo> <mn>6</mn> <mspace width="thinmathspace" /> <msubsup> <mtext>CO</mtext> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mspace width="0pt" height="0pt" depth=".2em" /> </mrow> </msubsup> <mo>+</mo> <mn>6</mn> <mspace width="thinmathspace" /> <msubsup> <mtext>H</mtext> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mspace width="0pt" height="0pt" depth=".2em" /> </mrow> </msubsup> <mtext>O</mtext> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle {\ce {C6H12O6 + 6O2 -> 6CO2 + 6H2O}}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/3b900a38a081015a895dbce7eb6a5d2699523fce" class="mwe-math-fallback-image-display mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.005ex; width:36.648ex; height:2.843ex;" alt="{\displaystyle {\ce {C6H12O6 + 6O2 -> 6CO2 + 6H2O}}}"></span> <span class="mwe-math-element"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle {\ce {C57H110O6 + (81 1/2) O2 -> 57CO2 + 55H2O}}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mrow class="MJX-TeXAtom-ORD"> <msubsup> <mtext>C</mtext> <mrow class="MJX-TeXAtom-ORD"> <mn>57</mn> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mspace width="0pt" height="0pt" depth=".2em" /> </mrow> </msubsup> <msubsup> <mtext>H</mtext> <mrow class="MJX-TeXAtom-ORD"> <mn>110</mn> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mspace width="0pt" height="0pt" depth=".2em" /> </mrow> </msubsup> <msubsup> <mtext>O</mtext> <mrow class="MJX-TeXAtom-ORD"> <mn>6</mn> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mspace width="0pt" height="0pt" depth=".2em" /> </mrow> </msubsup> <mo>+</mo> <mrow class="MJX-TeXAtom-ORD"> <mo stretchy="false">(</mo> <mn>81</mn> <mspace width="thinmathspace" /> <mstyle displaystyle="false" scriptlevel="0"> <mfrac> <mn>1</mn> <mn>2</mn> </mfrac> </mstyle> <mo stretchy="false">)</mo> </mrow> <msubsup> <mtext>O</mtext> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mspace width="0pt" height="0pt" depth=".2em" /> </mrow> </msubsup> <mo stretchy="false">⟶</mo> <mn>57</mn> <mspace width="thinmathspace" /> <msubsup> <mtext>CO</mtext> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mspace width="0pt" height="0pt" depth=".2em" /> </mrow> </msubsup> <mo>+</mo> <mn>55</mn> <mspace width="thinmathspace" /> <msubsup> <mtext>H</mtext> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mspace width="0pt" height="0pt" depth=".2em" /> </mrow> </msubsup> <mtext>O</mtext> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle {\ce {C57H110O6 + (81 1/2) O2 -> 57CO2 + 55H2O}}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/396ec72334a7746c2e20e9e16555b7478520e29a" class="mwe-math-fallback-image-display mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.171ex; width:45.246ex; height:3.509ex;" alt="{\displaystyle {\ce {C57H110O6 + (81 1/2) O2 -> 57CO2 + 55H2O}}}"></span> and some of the energy is used to convert <a href="/wiki/Adenosine_diphosphate" title="Adenosine diphosphate">ADP</a> into <a href="/wiki/Adenosine_triphosphate" title="Adenosine triphosphate">ATP</a>: </p> <style data-mw-deduplicate="TemplateStyles:r996643573">.mw-parser-output .block-indent{padding-left:3em;padding-right:0;overflow:hidden}</style><div class="block-indent" style="padding-left: 1.6em;">ADP + HPO<sub>4</sub><sup>2−</sup> → ATP + H<sub>2</sub>O</div> <p>The rest of the chemical energy of the carbohydrate or fat are converted into heat: the ATP is used as a sort of "energy currency", and some of the chemical energy it contains is used for other <a href="/wiki/Metabolism" title="Metabolism">metabolism</a> when ATP reacts with OH groups and eventually splits into ADP and phosphate (at each stage of a <a href="/wiki/Metabolic_pathway" title="Metabolic pathway">metabolic pathway</a>, some chemical energy is converted into heat). Only a tiny fraction of the original chemical energy is used for <a href="/wiki/Work_(physics)" title="Work (physics)">work</a>:<sup id="cite_ref-10" class="reference"><a href="#cite_note-10"><span class="cite-bracket">[</span>note 1<span class="cite-bracket">]</span></a></sup> </p> <dl><dd>gain in kinetic energy of a sprinter during a 100 m race: 4 kJ</dd> <dd>gain in gravitational potential energy of a 150 kg weight lifted through 2 metres: 3 kJ</dd> <dd>Daily food intake of a normal adult: 6–8 MJ</dd></dl> <p>It would appear that living organisms are remarkably <a href="/wiki/Energy_conversion_efficiency" title="Energy conversion efficiency">inefficient (in the physical sense)</a> in their use of the energy they receive (chemical or radiant energy); most <a href="/wiki/Machine" title="Machine">machines</a> manage higher efficiencies. In growing organisms the energy that is converted to heat serves a vital purpose, as it allows the organism tissue to be highly ordered with regard to the molecules it is built from. The <a href="/wiki/Second_law_of_thermodynamics" title="Second law of thermodynamics">second law of thermodynamics</a> states that energy (and matter) tends to become more evenly spread out across the universe: to concentrate energy (or matter) in one specific place, it is necessary to spread out a greater amount of energy (as heat) across the remainder of the universe ("the surroundings").<sup id="cite_ref-11" class="reference"><a href="#cite_note-11"><span class="cite-bracket">[</span>note 2<span class="cite-bracket">]</span></a></sup> Simpler organisms can achieve higher energy efficiencies than more complex ones, but the complex organisms can occupy <a href="/wiki/Ecological_niche" title="Ecological niche">ecological niches</a> that are not available to their simpler brethren. The conversion of a portion of the chemical energy to heat at each step in a metabolic pathway is the physical reason behind the pyramid of biomass observed in <a href="/wiki/Ecology" title="Ecology">ecology</a>. As an example, to take just the first step in the <a href="/wiki/Food_chain" title="Food chain">food chain</a>: of the estimated 124.7 Pg/a of carbon that is <a href="/wiki/Carbon_fixation" class="mw-redirect" title="Carbon fixation">fixed</a> by <a href="/wiki/Photosynthesis" title="Photosynthesis">photosynthesis</a>, 64.3 Pg/a (52%) are used for the metabolism of green plants,<sup id="cite_ref-12" class="reference"><a href="#cite_note-12"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup> i.e. reconverted into carbon dioxide and heat. </p> <div class="mw-heading mw-heading3"><h3 id="Earth_sciences">Earth sciences</h3></div> <p>In <a href="/wiki/Earth_science#earth's_energy" title="Earth science">geology</a>, <a href="/wiki/Continental_drift" title="Continental drift">continental drift</a>, <a href="/wiki/Mountain" title="Mountain">mountain ranges</a>, <a href="/wiki/Volcano" title="Volcano">volcanoes</a>, and <a href="/wiki/Earthquake" title="Earthquake">earthquakes</a> are phenomena that can be explained in terms of energy transformations in the Earth's interior,<sup id="cite_ref-13" class="reference"><a href="#cite_note-13"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup> while <a href="/wiki/Metereology" class="mw-redirect" title="Metereology">meteorological</a> phenomena like wind, rain, <a href="/wiki/Hail" title="Hail">hail</a>, snow, lightning, <a href="/wiki/Tornado" title="Tornado">tornadoes</a> and <a href="/wiki/Tropical_cyclone" title="Tropical cyclone">hurricanes</a> are all a result of energy transformations in our <a href="/wiki/Atmosphere" title="Atmosphere">atmosphere</a> brought about by <a href="/wiki/Solar_energy" title="Solar energy">solar energy</a>. </p><p>Sunlight is the main input to <a href="/wiki/Earth%27s_energy_budget" title="Earth's energy budget">Earth's energy budget</a> which accounts for its temperature and climate stability. Sunlight may be stored as gravitational potential energy after it strikes the Earth, as (for example when) water evaporates from oceans and is deposited upon mountains (where, after being released at a hydroelectric dam, it can be used to drive turbines or generators to produce electricity). Sunlight also drives most weather phenomena, save a few exceptions, like those generated by volcanic events for example. An example of a solar-mediated weather event is a hurricane, which occurs when large unstable areas of warm ocean, heated over months, suddenly give up some of their thermal energy to power a few days of violent air movement. </p><p>In a slower process, <a href="/wiki/Radioactive_decay" title="Radioactive decay">radioactive decay</a> of atoms in the core of the Earth releases heat. This thermal energy drives <a href="/wiki/Plate_tectonics" title="Plate tectonics">plate tectonics</a> and may lift mountains, via <a href="/wiki/Orogenesis" class="mw-redirect" title="Orogenesis">orogenesis</a>. This slow lifting represents a kind of gravitational potential <a href="/wiki/Energy_storage" title="Energy storage">energy storage</a> of the thermal energy, which may later be transformed into active kinetic energy during landslides, after a triggering event. Earthquakes also release stored elastic potential energy in rocks, a store that has been produced ultimately from the same radioactive heat sources. Thus, according to present understanding, familiar events such as landslides and earthquakes release energy that has been stored as potential energy in the Earth's gravitational field or elastic strain (mechanical potential energy) in rocks. Prior to this, they represent release of energy that has been stored in heavy atoms since the collapse of long-destroyed supernova stars (which created these atoms). </p> <div class="mw-heading mw-heading3"><h3 id="Cosmology">Cosmology</h3></div> <p>In <a href="/wiki/Physical_cosmology#Energy_of_the_cosmos" title="Physical cosmology">cosmology and astronomy</a> the phenomena of <a href="/wiki/Star" title="Star">stars</a>, <a href="/wiki/Nova" title="Nova">nova</a>, <a href="/wiki/Supernova" title="Supernova">supernova</a>, <a href="/wiki/Quasar" title="Quasar">quasars</a> and <a href="/wiki/Gamma-ray_burst" title="Gamma-ray burst">gamma-ray bursts</a> are the universe's highest-output energy transformations of matter. All <a href="https://en.wiktionary.org/wiki/stellar" class="extiw" title="wikt:stellar">stellar</a> phenomena (including solar activity) are driven by various kinds of energy transformations. Energy in such transformations is either from gravitational collapse of matter (usually molecular hydrogen) into various classes of astronomical objects (stars, black holes, etc.), or from nuclear fusion (of lighter elements, primarily hydrogen). </p><p>The <a href="/wiki/Nuclear_fusion" title="Nuclear fusion">nuclear fusion</a> of hydrogen in the Sun also releases another store of potential energy which was created at the time of the <a href="/wiki/Big_Bang" title="Big Bang">Big Bang</a>. At that time, according to theory, space expanded and the universe cooled too rapidly for hydrogen to completely fuse into heavier elements. This meant that hydrogen represents a store of potential energy that can be released by fusion. Such a fusion process is triggered by heat and pressure generated from gravitational collapse of hydrogen clouds when they produce stars, and some of the fusion energy is then transformed into sunlight. </p><p><span class="anchor" id="Physics"></span> </p> <div class="mw-heading mw-heading3"><h3 id="Quantum_mechanics">Quantum mechanics</h3></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Energy_operator" title="Energy operator">Energy operator</a></div> <p>In <a href="/wiki/Quantum_mechanics" title="Quantum mechanics">quantum mechanics</a>, energy is defined in terms of the <a href="/wiki/Hamiltonian_(quantum_mechanics)" title="Hamiltonian (quantum mechanics)">energy operator</a> (Hamiltonian) as a time derivative of the <a href="/wiki/Wave_function" title="Wave function">wave function</a>. The <a href="/wiki/Schr%C3%B6dinger_equation" title="Schrödinger equation">Schrödinger equation</a> equates the energy operator to the full energy of a particle or a system. Its results can be considered as a definition of measurement of energy in quantum mechanics. The Schrödinger equation describes the space- and time-dependence of a slowly changing (non-relativistic) <a href="/wiki/Wave_function" title="Wave function">wave function</a> of quantum systems. The solution of this equation for a bound system is discrete (a set of permitted states, each characterized by an <a href="/wiki/Energy_level" title="Energy level">energy level</a>) which results in the concept of <a href="/wiki/Quantum" title="Quantum">quanta</a>. In the solution of the Schrödinger equation for any oscillator (vibrator) and for electromagnetic waves in a vacuum, the resulting energy states are related to the frequency by <a href="/wiki/Planck%27s_relation" class="mw-redirect" title="Planck's relation">Planck's relation</a>: <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle E=h\nu }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>E</mi> <mo>=</mo> <mi>h</mi> <mi>ν</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle E=h\nu }</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/c6c0386dc6d9530519404f95570fcc8548ed2326" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:7.445ex; height:2.176ex;" alt="{\displaystyle E=h\nu }"></span> (where <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle h}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>h</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle h}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/b26be3e694314bc90c3215047e4a2010c6ee184a" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.339ex; height:2.176ex;" alt="{\displaystyle h}"></span> is the <a href="/wiki/Planck_constant" title="Planck constant">Planck constant</a> and <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \nu }"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>ν</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \nu }</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/c15bbbb971240cf328aba572178f091684585468" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.232ex; height:1.676ex;" alt="{\displaystyle \nu }"></span> the frequency). In the case of an electromagnetic wave these energy states are called quanta of light or <a href="/wiki/Photon" title="Photon">photons</a>. </p> <div class="mw-heading mw-heading3"><h3 id="Relativity">Relativity</h3></div> <p>When calculating kinetic energy (<a href="/wiki/Mechanical_work" class="mw-redirect" title="Mechanical work">work</a> to accelerate a <a href="/wiki/Mass" title="Mass">massive body</a> from zero <a href="/wiki/Speed" title="Speed">speed</a> to some finite speed) relativistically – using <a href="/wiki/Lorentz_transformations" class="mw-redirect" title="Lorentz transformations">Lorentz transformations</a> instead of <a href="/wiki/Newtonian_mechanics" class="mw-redirect" title="Newtonian mechanics">Newtonian mechanics</a> – Einstein discovered an unexpected by-product of these calculations to be an energy term which does not vanish at zero speed. He called it <a href="/wiki/Rest_energy" class="mw-redirect" title="Rest energy">rest energy</a>: energy which every massive body must possess even when being at rest. The amount of energy is directly proportional to the mass of the body: </p><p><span class="mwe-math-element"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle E_{0}=m_{0}c^{2},}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <msub> <mi>E</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>0</mn> </mrow> </msub> <mo>=</mo> <msub> <mi>m</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>0</mn> </mrow> </msub> <msup> <mi>c</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> <mo>,</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle E_{0}=m_{0}c^{2},}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/8cd0e37afe3b2ed97f701cadf87f770814caff73" class="mwe-math-fallback-image-display mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:11.67ex; height:3.009ex;" alt="{\displaystyle E_{0}=m_{0}c^{2},}"></span>where </p> <ul><li><i>m</i><sub>0</sub> is the <a href="/wiki/Rest_Mass" class="mw-redirect" title="Rest Mass">rest mass</a> of the body,</li> <li><i>c</i> is the <a href="/wiki/Speed_of_light" title="Speed of light">speed of light</a> in vacuum,</li> <li><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle E_{0}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <msub> <mi>E</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>0</mn> </mrow> </msub> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle E_{0}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/411d268de7b1cf300d7481e3fe59f3b20887e0d0" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:2.769ex; height:2.509ex;" alt="{\displaystyle E_{0}}"></span> is the rest energy.</li></ul> <p>For example, consider <a href="/wiki/Electron" title="Electron">electron</a>–<a href="/wiki/Positron" title="Positron">positron</a> annihilation, in which the rest energy of these two individual particles (equivalent to their rest mass) is converted to the radiant energy of the photons produced in the process. In this system the <a href="/wiki/Matter" title="Matter">matter</a> and <a href="/wiki/Antimatter" title="Antimatter">antimatter</a> (electrons and positrons) are destroyed and changed to non-matter (the photons). However, the total mass and total energy do not change during this interaction. The photons each have no rest mass but nonetheless have radiant energy which exhibits the same inertia as did the two original particles. This is a reversible process – the inverse process is called <a href="/wiki/Pair_creation" class="mw-redirect" title="Pair creation">pair creation</a> – in which the rest mass of particles is created from the radiant energy of two (or more) annihilating photons. </p><p>In general relativity, the <a href="/wiki/Stress%E2%80%93energy_tensor" title="Stress–energy tensor">stress–energy tensor</a> serves as the source term for the gravitational field, in rough analogy to the way mass serves as the source term in the non-relativistic Newtonian approximation.<sup id="cite_ref-MTW_14-0" class="reference"><a href="#cite_note-MTW-14"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup> </p><p>Energy and mass are manifestations of one and the same underlying physical property of a system. This property is responsible for the inertia and strength of gravitational interaction of the system ("mass manifestations"), and is also responsible for the potential ability of the system to perform work or heating ("energy manifestations"), subject to the limitations of other physical laws. </p><p>In <a href="/wiki/Classical_physics" title="Classical physics">classical physics</a>, energy is a scalar quantity, the <a href="/wiki/Canonical_conjugate" class="mw-redirect" title="Canonical conjugate">canonical conjugate</a> to time. In <a href="/wiki/Special_relativity" title="Special relativity">special relativity</a> energy is also a scalar (although not a <a href="/wiki/Lorentz_scalar" title="Lorentz scalar">Lorentz scalar</a> but a time component of the <a href="/wiki/Energy%E2%80%93momentum_4-vector" class="mw-redirect" title="Energy–momentum 4-vector">energy–momentum 4-vector</a>).<sup id="cite_ref-MTW_14-1" class="reference"><a href="#cite_note-MTW-14"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup> In other words, energy is invariant with respect to rotations of <a href="/wiki/Space" title="Space">space</a>, but not invariant with respect to rotations of <a href="/wiki/Spacetime" title="Spacetime">spacetime</a> (= <a href="/wiki/Lorentz_boost" class="mw-redirect" title="Lorentz boost">boosts</a>). </p> <div class="mw-heading mw-heading2"><h2 id="Transformation">Transformation</h2></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Energy_transformation" title="Energy transformation">Energy transformation</a></div> <table class="wikitable" style="text-align:center;"> <caption>Some forms of <a href="/wiki/Energy_transfer" class="mw-redirect" title="Energy transfer">transfer</a> of energy ("energy in transit") from one object or system to another </caption> <tbody><tr> <th>Type of transfer <a href="/wiki/Thermodynamic_process" title="Thermodynamic process">process</a></th> <th>Description </th></tr> <tr> <td><a href="/wiki/Heat" title="Heat">Heat</a> </td> <td>equal amount of <a href="/wiki/Thermal_energy#Differentiation_from_heat" title="Thermal energy">thermal energy</a> in transit spontaneously towards a lower-<a href="/wiki/Temperature" title="Temperature">temperature</a> object </td></tr> <tr> <td><a href="/wiki/Work_(physics)" title="Work (physics)">Work</a> </td> <td>equal amount of energy in transit due to a displacement in the direction of an applied <a href="/wiki/Force" title="Force">force</a> </td></tr> <tr> <td>Transfer of material </td> <td>equal amount of energy carried by <a href="/wiki/Matter" title="Matter">matter</a> that is moving from one system to another </td></tr> </tbody></table> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Turbogenerator01.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/c/ca/Turbogenerator01.jpg/220px-Turbogenerator01.jpg" decoding="async" width="220" height="157" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/c/ca/Turbogenerator01.jpg/330px-Turbogenerator01.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/c/ca/Turbogenerator01.jpg/440px-Turbogenerator01.jpg 2x" data-file-width="2126" data-file-height="1519" /></a><figcaption>A <a href="/wiki/Turbo_generator" title="Turbo generator">turbo generator</a> transforms the energy of pressurized steam into electrical energy.</figcaption></figure> <p>Energy may be <a href="/wiki/Energy_transformation" title="Energy transformation">transformed</a> between different forms at various <a href="/wiki/Energy_conversion_efficiency" title="Energy conversion efficiency">efficiencies</a>. Items that transform between these forms are called <a href="/wiki/Transducer" title="Transducer">transducers</a>. Examples of transducers include a <a href="/wiki/Battery_(electric)" class="mw-redirect" title="Battery (electric)">battery</a> (from <a href="/wiki/Chemical_energy" title="Chemical energy">chemical energy</a> to <a href="/wiki/Electric_energy" class="mw-redirect" title="Electric energy">electric energy</a>), a dam (from <a href="/wiki/Gravitational_potential_energy" class="mw-redirect" title="Gravitational potential energy">gravitational potential energy</a> to <a href="/wiki/Kinetic_energy" title="Kinetic energy">kinetic energy</a> of moving water (and the blades of a <a href="/wiki/Turbine" title="Turbine">turbine</a>) and ultimately to <a href="/wiki/Electric_energy" class="mw-redirect" title="Electric energy">electric energy</a> through an <a href="/wiki/Electric_generator" title="Electric generator">electric generator</a>), and a <a href="/wiki/Heat_engine" title="Heat engine">heat engine</a> (from heat to work). </p><p>Examples of energy transformation include generating <a href="/wiki/Electric_energy" class="mw-redirect" title="Electric energy">electric energy</a> from heat energy via a steam turbine, or lifting an object against gravity using electrical energy driving a crane motor. Lifting against gravity performs mechanical work on the object and stores gravitational potential energy in the object. If the object falls to the ground, gravity does mechanical work on the object which transforms the potential energy in the gravitational field to the kinetic energy released as heat on impact with the ground. The Sun transforms <a href="/wiki/Nuclear_potential_energy" class="mw-redirect" title="Nuclear potential energy">nuclear potential energy</a> to other forms of energy; its total mass does not decrease due to that itself (since it still contains the same total energy even in different forms) but its mass does decrease when the energy escapes out to its surroundings, largely as <a href="/wiki/Radiant_energy" title="Radiant energy">radiant energy</a>. </p><p>There are strict limits to how efficiently heat can be converted into <a href="/wiki/Work_(physics)" title="Work (physics)">work</a> in a cyclic process, e.g. in a heat engine, as described by <a href="/wiki/Carnot%27s_theorem_(thermodynamics)" title="Carnot's theorem (thermodynamics)">Carnot's theorem</a> and the <a href="/wiki/Second_law_of_thermodynamics" title="Second law of thermodynamics">second law of thermodynamics</a>. However, some energy transformations can be quite efficient. The direction of transformations in energy (what kind of energy is transformed to what other kind) is often determined by <a href="/wiki/Entropy" title="Entropy">entropy</a> (equal energy spread among all available <a href="/wiki/Degrees_of_freedom_(physics_and_chemistry)" title="Degrees of freedom (physics and chemistry)">degrees of freedom</a>) considerations. In practice all energy transformations are permitted on a small scale, but certain larger transformations are not permitted because it is statistically unlikely that energy or matter will randomly move into more concentrated forms or smaller spaces. </p><p>Energy transformations in the universe over time are characterized by various kinds of potential energy, that has been available since the <a href="/wiki/Big_Bang" title="Big Bang">Big Bang</a>, being "released" (transformed to more active types of energy such as kinetic or radiant energy) when a triggering mechanism is available. Familiar examples of such processes include <a href="/wiki/Nucleosynthesis" title="Nucleosynthesis">nucleosynthesis</a>, a process ultimately using the gravitational potential energy released from the <a href="/wiki/Gravitational_collapse" title="Gravitational collapse">gravitational collapse</a> of <a href="/wiki/Supernova" title="Supernova">supernovae</a> to "store" energy in the creation of heavy isotopes (such as <a href="/wiki/Uranium" title="Uranium">uranium</a> and <a href="/wiki/Thorium" title="Thorium">thorium</a>), and <a href="/wiki/Nuclear_decay" class="mw-redirect" title="Nuclear decay">nuclear decay</a>, a process in which energy is released that was originally stored in these heavy elements, before they were incorporated into the Solar System and the Earth. This energy is triggered and released in nuclear <a href="/wiki/Fission_bomb" class="mw-redirect" title="Fission bomb">fission bombs</a> or in civil nuclear power generation. Similarly, in the case of a <a href="/wiki/Chemical_explosive" class="mw-redirect" title="Chemical explosive">chemical explosion</a>, <a href="/wiki/Chemical_potential" title="Chemical potential">chemical potential</a> energy is transformed to <a href="/wiki/Kinetic_energy" title="Kinetic energy">kinetic</a> and <a href="/wiki/Thermal_energy" title="Thermal energy">thermal energy</a> in a very short time. </p><p>Yet another example is that of a <a href="/wiki/Pendulum" title="Pendulum">pendulum</a>. At its highest points the <a href="/wiki/Kinetic_energy" title="Kinetic energy">kinetic energy</a> is zero and the <a href="/wiki/Gravitational_potential_energy" class="mw-redirect" title="Gravitational potential energy">gravitational potential energy</a> is at its maximum. At its lowest point the <a href="/wiki/Kinetic_energy" title="Kinetic energy">kinetic energy</a> is at its maximum and is equal to the decrease in <a href="/wiki/Potential_energy" title="Potential energy">potential energy</a>. If one (unrealistically) assumes that there is no <a href="/wiki/Friction" title="Friction">friction</a> or other losses, the conversion of energy between these processes would be perfect, and the <a href="/wiki/Pendulum" title="Pendulum">pendulum</a> would continue swinging forever. </p><p>Energy is also transferred from potential energy (<span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle E_{p}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <msub> <mi>E</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>p</mi> </mrow> </msub> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle E_{p}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/74b041d193c6b8de0113f5a5e8d8e00d05afa339" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.005ex; width:2.774ex; height:2.843ex;" alt="{\displaystyle E_{p}}"></span>) to kinetic energy (<span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle E_{k}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <msub> <mi>E</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>k</mi> </mrow> </msub> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle E_{k}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/7587849b44d775263271e89499f4327eeac5dc81" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:2.804ex; height:2.509ex;" alt="{\displaystyle E_{k}}"></span>) and then back to potential energy constantly. This is referred to as conservation of energy. In this <a href="/wiki/Isolated_system" title="Isolated system">isolated system</a>, energy cannot be created or destroyed; therefore, the initial energy and the final energy will be equal to each other. This can be demonstrated by the following: </p> <table role="presentation" style="border-collapse:collapse; margin:0 0 0 0em; border:none;"><tbody><tr><td style="vertical-align:middle; border:none; padding:0;" class="nowrap"><span class="mwe-math-element"><span class="mwe-math-mathml-display mwe-math-mathml-a11y" style="display: none;"><math display="block" xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle E_{pi}+E_{ki}=E_{pF}+E_{kF}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <msub> <mi>E</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>p</mi> <mi>i</mi> </mrow> </msub> <mo>+</mo> <msub> <mi>E</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>k</mi> <mi>i</mi> </mrow> </msub> <mo>=</mo> <msub> <mi>E</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>p</mi> <mi>F</mi> </mrow> </msub> <mo>+</mo> <msub> <mi>E</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>k</mi> <mi>F</mi> </mrow> </msub> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle E_{pi}+E_{ki}=E_{pF}+E_{kF}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/8971697eb06979d8aed17dbf2954a4e280b6b0c3" class="mwe-math-fallback-image-display mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.005ex; width:23.533ex; height:2.843ex;" alt="{\displaystyle E_{pi}+E_{ki}=E_{pF}+E_{kF}}"></span></td> <td style="vertical-align:middle; width:99%; border:none; padding:0;"></td> <td style="vertical-align:middle; border:none; padding:0;" class="nowrap"><b>(<span id="math_4" class="reference nourlexpansion" style="font-weight:bold;">4</span>)</b></td></tr></tbody></table> <p>The equation can then be simplified further since <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle E_{p}=mgh}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <msub> <mi>E</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>p</mi> </mrow> </msub> <mo>=</mo> <mi>m</mi> <mi>g</mi> <mi>h</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle E_{p}=mgh}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/71be3ed0d4d97cf9428feafafc7b7f41b3326038" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.005ex; width:10.368ex; height:2.843ex;" alt="{\displaystyle E_{p}=mgh}"></span> (mass times acceleration due to gravity times the height) and <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\textstyle E_{k}={\frac {1}{2}}mv^{2}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="false" scriptlevel="0"> <msub> <mi>E</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>k</mi> </mrow> </msub> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>1</mn> <mn>2</mn> </mfrac> </mrow> <mi>m</mi> <msup> <mi>v</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> </mstyle> </mrow> <annotation encoding="application/x-tex">{\textstyle E_{k}={\frac {1}{2}}mv^{2}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/1e88f93ee95d393520dd8029690ae8206424e57a" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.171ex; width:11.783ex; height:3.509ex;" alt="{\textstyle E_{k}={\frac {1}{2}}mv^{2}}"></span> (half mass times velocity squared). Then the total amount of energy can be found by adding <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle E_{p}+E_{k}=E_{\text{total}}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <msub> <mi>E</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>p</mi> </mrow> </msub> <mo>+</mo> <msub> <mi>E</mi> <mrow class="MJX-TeXAtom-ORD"> <mi>k</mi> </mrow> </msub> <mo>=</mo> <msub> <mi>E</mi> <mrow class="MJX-TeXAtom-ORD"> <mtext>total</mtext> </mrow> </msub> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle E_{p}+E_{k}=E_{\text{total}}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/3b84a73645308eaaea91262ba950fee2e6ab28e0" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.005ex; width:16.845ex; height:2.843ex;" alt="{\displaystyle E_{p}+E_{k}=E_{\text{total}}}"></span>. </p> <div class="mw-heading mw-heading3"><h3 id="Conservation_of_energy_and_mass_in_transformation">Conservation of energy and mass in transformation</h3></div> <p>Energy gives rise to weight when it is trapped in a system with zero momentum, where it can be weighed. It is also equivalent to mass, and this mass is always associated with it. Mass is also equivalent to a certain amount of energy, and likewise always appears associated with it, as described in <a href="/wiki/Mass%E2%80%93energy_equivalence" title="Mass–energy equivalence">mass–energy equivalence</a>. The formula <i>E</i> = <i>mc</i>², derived by <a href="/wiki/Albert_Einstein" title="Albert Einstein">Albert Einstein</a> (1905) quantifies the relationship between <a href="/wiki/Relativistic_mass" class="mw-redirect" title="Relativistic mass">relativistic mass</a> and energy within the concept of special relativity. In different theoretical frameworks, similar formulas were derived by <a href="/wiki/J.J._Thomson" class="mw-redirect" title="J.J. Thomson">J.J. Thomson</a> (1881), <a href="/wiki/Henri_Poincar%C3%A9" title="Henri Poincaré">Henri Poincaré</a> (1900), <a href="/wiki/Friedrich_Hasen%C3%B6hrl" title="Friedrich Hasenöhrl">Friedrich Hasenöhrl</a> (1904) and others (see <a href="/wiki/Mass%E2%80%93energy_equivalence#History" title="Mass–energy equivalence">Mass–energy equivalence#History</a> for further information). </p><p>Part of the rest energy (equivalent to rest mass) of <a href="/wiki/Matter" title="Matter">matter</a> may be converted to other forms of energy (still exhibiting mass), but neither energy nor mass can be destroyed; rather, both remain constant during any process. However, since <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle c^{2}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <msup> <mi>c</mi> <mrow class="MJX-TeXAtom-ORD"> <mn>2</mn> </mrow> </msup> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle c^{2}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/87f3386a00382ce857fb0b3b04b9fa2bbe5cfae9" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:2.061ex; height:2.676ex;" alt="{\displaystyle c^{2}}"></span> is extremely large relative to ordinary human scales, the conversion of an everyday amount of rest mass (for example, 1 kg) from rest energy to other forms of energy (such as kinetic energy, thermal energy, or the radiant energy carried by light and other radiation) can liberate tremendous amounts of energy (~<span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle 9\times 10^{16}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mn>9</mn> <mo>×</mo> <msup> <mn>10</mn> <mrow class="MJX-TeXAtom-ORD"> <mn>16</mn> </mrow> </msup> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle 9\times 10^{16}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/3cf8f60072578a1ced892d8713988ea02726a895" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:8.204ex; height:2.676ex;" alt="{\displaystyle 9\times 10^{16}}"></span> joules = 21 megatons of TNT), as can be seen in <a href="/wiki/Nuclear_reactor" title="Nuclear reactor">nuclear reactors</a> and nuclear weapons. </p><p>Conversely, the mass equivalent of an everyday amount energy is minuscule, which is why a loss of energy (loss of mass) from most systems is difficult to measure on a weighing scale, unless the energy loss is very large. Examples of large transformations between rest energy (of matter) and other forms of energy (e.g., kinetic energy into particles with rest mass) are found in <a href="/wiki/Nuclear_physics" title="Nuclear physics">nuclear physics</a> and <a href="/wiki/Particle_physics" title="Particle physics">particle physics</a>. Often, however, the complete conversion of matter (such as atoms) to non-matter (such as photons) is forbidden by <a href="/wiki/Conservation_law" title="Conservation law">conservation laws</a>. </p> <div class="mw-heading mw-heading3"><h3 id="Reversible_and_non-reversible_transformations">Reversible and non-reversible transformations</h3></div> <p>Thermodynamics divides energy transformation into two kinds: <a href="/wiki/Reversible_process_(thermodynamics)" title="Reversible process (thermodynamics)">reversible processes</a> and <a href="/wiki/Irreversible_process" title="Irreversible process">irreversible processes</a>. An irreversible process is one in which energy is dissipated (spread) into empty energy states available in a volume, from which it cannot be recovered into more concentrated forms (fewer quantum states), without degradation of even more energy. A reversible process is one in which this sort of dissipation does not happen. For example, conversion of energy from one type of potential field to another is reversible, as in the pendulum system described above. </p><p>In processes where heat is generated, quantum states of lower energy, present as possible excitations in fields between atoms, act as a reservoir for part of the energy, from which it cannot be recovered, in order to be converted with 100% efficiency into other forms of energy. In this case, the energy must partly stay as thermal energy and cannot be completely recovered as usable energy, except at the price of an increase in some other kind of heat-like increase in disorder in quantum states, in the universe (such as an expansion of matter, or a randomization in a crystal). </p><p>As the universe evolves with time, more and more of its energy becomes trapped in irreversible states (i.e., as heat or as other kinds of increases in disorder). This has led to the hypothesis of the inevitable thermodynamic <a href="/wiki/Heat_death_of_the_universe" title="Heat death of the universe">heat death of the universe</a>. In this heat death the energy of the universe does not change, but the fraction of energy which is available to do work through a <a href="/wiki/Heat_engine" title="Heat engine">heat engine</a>, or be transformed to other usable forms of energy (through the use of generators attached to heat engines), continues to decrease. </p> <div class="mw-heading mw-heading2"><h2 id="Conservation_of_energy">Conservation of energy</h2></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Conservation_of_energy" title="Conservation of energy">Conservation of energy</a></div> <p>The fact that energy can be neither created nor destroyed is called the law of <a href="/wiki/Conservation_of_energy" title="Conservation of energy">conservation of energy</a>. In the form of the <a href="/wiki/First_law_of_thermodynamics" title="First law of thermodynamics">first law of thermodynamics</a>, this states that a <a href="/wiki/Closed_system" title="Closed system">closed system</a>'s energy is constant unless energy is transferred in or out as <a href="/wiki/Work_(thermodynamics)" title="Work (thermodynamics)">work</a> or <a href="/wiki/Heat" title="Heat">heat</a>, and that no energy is lost in transfer. The total inflow of energy into a system must equal the total outflow of energy from the system, plus the change in the energy contained within the system. Whenever one measures (or calculates) the total energy of a system of particles whose interactions do not depend explicitly on time, it is found that the total energy of the system always remains constant.<sup id="cite_ref-15" class="reference"><a href="#cite_note-15"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup> </p><p>While heat can always be fully converted into work in a reversible isothermal expansion of an ideal gas, for cyclic processes of practical interest in <a href="/wiki/Heat_engine" title="Heat engine">heat engines</a> the <a href="/wiki/Second_law_of_thermodynamics" title="Second law of thermodynamics">second law of thermodynamics</a> states that the system doing work always loses some energy as <a href="/wiki/Waste_heat" title="Waste heat">waste heat</a>. This creates a limit to the amount of heat energy that can do work in a cyclic process, a limit called the <a href="/wiki/Available_energy" class="mw-redirect" title="Available energy">available energy</a>. Mechanical and other forms of energy can be transformed in the other direction into <a href="/wiki/Thermal_energy" title="Thermal energy">thermal energy</a> without such limitations.<sup id="cite_ref-thermo-laws_16-0" class="reference"><a href="#cite_note-thermo-laws-16"><span class="cite-bracket">[</span>14<span class="cite-bracket">]</span></a></sup> The total energy of a system can be calculated by adding up all forms of energy in the system. </p><p><a href="/wiki/Richard_Feynman" title="Richard Feynman">Richard Feynman</a> said during a 1961 lecture:<sup id="cite_ref-RPF1_17-0" class="reference"><a href="#cite_note-RPF1-17"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup> </p> <style data-mw-deduplicate="TemplateStyles:r1244412712">.mw-parser-output .templatequote{overflow:hidden;margin:1em 0;padding:0 32px}.mw-parser-output .templatequotecite{line-height:1.5em;text-align:left;margin-top:0}@media(min-width:500px){.mw-parser-output .templatequotecite{padding-left:1.6em}}</style><blockquote class="templatequote"><p>There is a fact, or if you wish, a <i>law</i>, governing all natural phenomena that are known to date. There is no known exception to this law – it is exact so far as we know. The law is called the <i><a href="/wiki/Conservation_of_energy" title="Conservation of energy">conservation of energy</a></i>. It states that there is a certain quantity, which we call energy, that does not change in manifold changes which nature undergoes. That is a most abstract idea, because it is a mathematical principle; it says that there is a numerical quantity which does not change when something happens. It is not a description of a mechanism, or anything concrete; it is just a strange fact that we can calculate some number and when we finish watching nature go through her tricks and calculate the number again, it is the same.</p><div class="templatequotecite">— <cite><i><a href="/wiki/The_Feynman_Lectures_on_Physics" title="The Feynman Lectures on Physics">The Feynman Lectures on Physics</a></i></cite></div></blockquote> <p>Most kinds of energy (with gravitational energy being a notable exception)<sup id="cite_ref-18" class="reference"><a href="#cite_note-18"><span class="cite-bracket">[</span>16<span class="cite-bracket">]</span></a></sup> are subject to strict local conservation laws as well. In this case, energy can only be exchanged between adjacent regions of space, and all observers agree as to the volumetric density of energy in any given space. There is also a global law of conservation of energy, stating that the total energy of the universe cannot change; this is a corollary of the local law, but not vice versa.<sup id="cite_ref-thermo-laws_16-1" class="reference"><a href="#cite_note-thermo-laws-16"><span class="cite-bracket">[</span>14<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-RPF1_17-1" class="reference"><a href="#cite_note-RPF1-17"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup> </p><p>This law is a fundamental principle of physics. As shown rigorously by <a href="/wiki/Noether%27s_theorem" title="Noether's theorem">Noether's theorem</a>, the conservation of energy is a mathematical consequence of <a href="/wiki/Translational_symmetry" title="Translational symmetry">translational symmetry</a> of time,<sup id="cite_ref-19" class="reference"><a href="#cite_note-19"><span class="cite-bracket">[</span>17<span class="cite-bracket">]</span></a></sup> a property of most phenomena below the cosmic scale that makes them independent of their locations on the time coordinate. Put differently, yesterday, today, and tomorrow are physically indistinguishable. This is because energy is the quantity which is <a href="/wiki/Canonical_conjugate" class="mw-redirect" title="Canonical conjugate">canonical conjugate</a> to time. This mathematical entanglement of energy and time also results in the uncertainty principle – it is impossible to define the exact amount of energy during any definite time interval (though this is practically significant only for very short time intervals). The uncertainty principle should not be confused with <a href="/wiki/Energy_conservation" title="Energy conservation">energy conservation</a> – rather it provides mathematical limits to which energy can in principle be defined and measured. </p><p>Each of the basic forces of nature is associated with a different type of potential energy, and all types of potential energy (like all other types of energy) appear as system <a href="/wiki/Mass" title="Mass">mass</a>, whenever present. For example, a compressed spring will be slightly more massive than before it was compressed. Likewise, whenever energy is transferred between systems by any mechanism, an associated mass is transferred with it. </p><p>In <a href="/wiki/Quantum_mechanics" title="Quantum mechanics">quantum mechanics</a> energy is expressed using the <a href="/wiki/Hamiltonian_operator" class="mw-redirect" title="Hamiltonian operator">Hamiltonian operator</a>. On any time scales, the uncertainty in the energy is by </p> <dl><dd><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \Delta E\Delta t\geq {\frac {\hbar }{2}}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi mathvariant="normal">Δ</mi> <mi>E</mi> <mi mathvariant="normal">Δ</mi> <mi>t</mi> <mo>≥</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mi class="MJX-variant">ℏ</mi> <mn>2</mn> </mfrac> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \Delta E\Delta t\geq {\frac {\hbar }{2}}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/b3b265d159ccfc0708c879a3959861262fdf50f2" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -1.838ex; width:11.728ex; height:5.343ex;" alt="{\displaystyle \Delta E\Delta t\geq {\frac {\hbar }{2}}}"></span></dd></dl> <p>which is similar in form to the <a href="/wiki/Heisenberg_Uncertainty_Principle" class="mw-redirect" title="Heisenberg Uncertainty Principle">Heisenberg Uncertainty Principle</a> (but not really mathematically equivalent thereto, since <i>H</i> and <i>t</i> are not dynamically conjugate variables, neither in classical nor in quantum mechanics). </p><p>In <a href="/wiki/Particle_physics" title="Particle physics">particle physics</a>, this inequality permits a qualitative understanding of <a href="/wiki/Virtual_particles" class="mw-redirect" title="Virtual particles">virtual particles</a>, which carry <a href="/wiki/Momentum" title="Momentum">momentum</a>. The exchange of virtual particles with real particles is responsible for the creation of all known <a href="/wiki/Fundamental_forces" class="mw-redirect" title="Fundamental forces">fundamental forces</a> (more accurately known as <a href="/wiki/Fundamental_interactions" class="mw-redirect" title="Fundamental interactions">fundamental interactions</a>). <a href="/wiki/Virtual_photons" class="mw-redirect" title="Virtual photons">Virtual photons</a> are also responsible for the electrostatic interaction between <a href="/wiki/Electric_charge" title="Electric charge">electric charges</a> (which results in <a href="/wiki/Coulomb%27s_law" title="Coulomb's law">Coulomb's law</a>), for <a href="/wiki/Spontaneous_fission" title="Spontaneous fission">spontaneous</a> radiative decay of excited atomic and nuclear states, for the <a href="/wiki/Casimir_force" class="mw-redirect" title="Casimir force">Casimir force</a>, for the <a href="/wiki/Van_der_Waals_force" title="Van der Waals force">Van der Waals force</a> and some other observable phenomena. </p> <div class="mw-heading mw-heading2"><h2 id="Energy_transfer">Energy transfer</h2></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">"Energy transfer" redirects here. For the pipeline company, see <a href="/wiki/Energy_Transfer_Partners" title="Energy Transfer Partners">Energy Transfer Partners</a>.</div> <div class="mw-heading mw-heading3"><h3 id="Closed_systems">Closed systems</h3></div> <p>Energy transfer can be considered for the special case of systems which are <a href="/wiki/Closed_system" title="Closed system">closed</a> to transfers of matter. The portion of the energy which is transferred by <a href="/wiki/Conservative_force" title="Conservative force">conservative forces</a> over a distance is measured as the <a href="/wiki/Work_(thermodynamics)" title="Work (thermodynamics)">work</a> the source system does on the receiving system. The portion of the energy which does not do work during the transfer is called <a href="/wiki/Heat" title="Heat">heat</a>.<sup id="cite_ref-20" class="reference"><a href="#cite_note-20"><span class="cite-bracket">[</span>note 3<span class="cite-bracket">]</span></a></sup> Energy can be transferred between systems in a variety of ways. Examples include the transmission of <a href="/wiki/Electromagnetic_energy" class="mw-redirect" title="Electromagnetic energy">electromagnetic energy</a> via photons, physical collisions which transfer <a href="/wiki/Kinetic_energy" title="Kinetic energy">kinetic energy</a>,<sup id="cite_ref-21" class="reference"><a href="#cite_note-21"><span class="cite-bracket">[</span>note 4<span class="cite-bracket">]</span></a></sup> <a href="/wiki/Tidal_interactions" class="mw-redirect" title="Tidal interactions">tidal interactions</a>,<sup id="cite_ref-22" class="reference"><a href="#cite_note-22"><span class="cite-bracket">[</span>18<span class="cite-bracket">]</span></a></sup> and the conductive transfer of <a href="/wiki/Thermal_energy" title="Thermal energy">thermal energy</a>. </p><p>Energy is strictly conserved and is also locally conserved wherever it can be defined. In thermodynamics, for closed systems, the process of energy transfer is described by the <a href="/wiki/First_law_of_thermodynamics" title="First law of thermodynamics">first law</a>:<sup id="cite_ref-23" class="reference"><a href="#cite_note-23"><span class="cite-bracket">[</span>note 5<span class="cite-bracket">]</span></a></sup> </p> <table role="presentation" style="border-collapse:collapse; margin:0 0 0 1.6em; border:none;"><tbody><tr><td style="vertical-align:middle; border:none; padding:0;" class="nowrap"><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \Delta {}E=W+Q}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi mathvariant="normal">Δ</mi> <mrow class="MJX-TeXAtom-ORD"> </mrow> <mi>E</mi> <mo>=</mo> <mi>W</mi> <mo>+</mo> <mi>Q</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \Delta {}E=W+Q}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/9252ffa5a7e4371111bb26656bb80200354237b6" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:13.924ex; height:2.509ex;" alt="{\displaystyle \Delta {}E=W+Q}"></span></td> <td style="vertical-align:middle; width:99%; border:none; padding:0;"></td> <td style="vertical-align:middle; border:none; padding:0;" class="nowrap"><b>(<span id="math_1" class="reference nourlexpansion" style="font-weight:bold;">1</span>)</b></td></tr></tbody></table> <p>where <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle E}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>E</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle E}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/4232c9de2ee3eec0a9c0a19b15ab92daa6223f9b" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:1.776ex; height:2.176ex;" alt="{\displaystyle E}"></span> is the amount of energy transferred, <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle W}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>W</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle W}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/54a9c4c547f4d6111f81946cad242b18298d70b7" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:2.435ex; height:2.176ex;" alt="{\displaystyle W}"></span>  represents the work done on or by the system, and <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle Q}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>Q</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle Q}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/8752c7023b4b3286800fe3238271bbca681219ed" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:1.838ex; height:2.509ex;" alt="{\displaystyle Q}"></span> represents the heat flow into or out of the system. As a simplification, the heat term, <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle Q}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>Q</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle Q}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/8752c7023b4b3286800fe3238271bbca681219ed" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:1.838ex; height:2.509ex;" alt="{\displaystyle Q}"></span>, can sometimes be ignored, especially for fast processes involving gases, which are poor conductors of heat, or when the <a href="/wiki/Thermal_efficiency" title="Thermal efficiency">thermal efficiency</a> of the transfer is high. For such <a href="/wiki/Adiabatic_process" title="Adiabatic process">adiabatic processes</a>, </p> <table role="presentation" style="border-collapse:collapse; margin:0 0 0 1.6em; border:none;"><tbody><tr><td style="vertical-align:middle; border:none; padding:0;" class="nowrap"><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \Delta {}E=W}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi mathvariant="normal">Δ</mi> <mrow class="MJX-TeXAtom-ORD"> </mrow> <mi>E</mi> <mo>=</mo> <mi>W</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \Delta {}E=W}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/16b893cb5af7bf1908f6e7fe254610817403345d" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:9.245ex; height:2.176ex;" alt="{\displaystyle \Delta {}E=W}"></span></td> <td style="vertical-align:middle; width:99%; border:none; padding:0;"></td> <td style="vertical-align:middle; border:none; padding:0;" class="nowrap"><b>(<span id="math_2" class="reference nourlexpansion" style="font-weight:bold;">2</span>)</b></td></tr></tbody></table> <p>This simplified equation is the one used to define the <a href="/wiki/Joule" title="Joule">joule</a>, for example. </p> <div class="mw-heading mw-heading3"><h3 id="Open_systems">Open systems</h3></div> <p>Beyond the constraints of closed systems, <a href="/wiki/Thermodynamic_system#Open_system" title="Thermodynamic system">open systems</a> can gain or lose energy in association with matter transfer (this process is illustrated by injection of an air-fuel mixture into a car engine, a system which gains in energy thereby, without addition of either work or heat). Denoting this energy by <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle E_{\text{matter}}}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <msub> <mi>E</mi> <mrow class="MJX-TeXAtom-ORD"> <mtext>matter</mtext> </mrow> </msub> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle E_{\text{matter}}}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/236f3684ef84fca2b3219b14ca87f0dd7b3f42a2" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:6.792ex; height:2.509ex;" alt="{\displaystyle E_{\text{matter}}}"></span>, one may write </p> <table role="presentation" style="border-collapse:collapse; margin:0 0 0 1.6em; border:none;"><tbody><tr><td style="vertical-align:middle; border:none; padding:0;" class="nowrap"><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \Delta E=W+Q+E_{\text{matter}}.}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi mathvariant="normal">Δ</mi> <mi>E</mi> <mo>=</mo> <mi>W</mi> <mo>+</mo> <mi>Q</mi> <mo>+</mo> <msub> <mi>E</mi> <mrow class="MJX-TeXAtom-ORD"> <mtext>matter</mtext> </mrow> </msub> <mo>.</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \Delta E=W+Q+E_{\text{matter}}.}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/8efdb11bf2a70131a928291a0f7dadc5887a9f73" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:24.203ex; height:2.509ex;" alt="{\displaystyle \Delta E=W+Q+E_{\text{matter}}.}"></span></td> <td style="vertical-align:middle; width:99%; border:none; padding:0;"></td> <td style="vertical-align:middle; border:none; padding:0;" class="nowrap"><b>(<span id="math_3" class="reference nourlexpansion" style="font-weight:bold;">3</span>)</b></td></tr></tbody></table> <div class="mw-heading mw-heading2"><h2 id="Thermodynamics">Thermodynamics</h2></div> <div class="mw-heading mw-heading3"><h3 id="Internal_energy">Internal energy</h3></div> <p><a href="/wiki/Internal_energy" title="Internal energy">Internal energy</a> is the sum of all microscopic forms of energy of a system. It is the energy needed to create the system. It is related to the potential energy, e.g., molecular structure, crystal structure, and other geometric aspects, as well as the motion of the particles, in form of kinetic energy. Thermodynamics is chiefly concerned with changes in internal energy and not its absolute value, which is impossible to determine with thermodynamics alone.<sup id="cite_ref-klotz_24-0" class="reference"><a href="#cite_note-klotz-24"><span class="cite-bracket">[</span>19<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="First_law_of_thermodynamics">First law of thermodynamics</h3></div> <p>The <a href="/wiki/First_law_of_thermodynamics" title="First law of thermodynamics">first law of thermodynamics</a> asserts that the total energy of a system and its surroundings (but not necessarily <a href="/wiki/Thermodynamic_free_energy" title="Thermodynamic free energy">thermodynamic free energy</a>) is always conserved<sup id="cite_ref-KK_25-0" class="reference"><a href="#cite_note-KK-25"><span class="cite-bracket">[</span>20<span class="cite-bracket">]</span></a></sup> and that heat flow is a form of energy transfer. For homogeneous systems, with a well-defined temperature and pressure, a commonly used corollary of the first law is that, for a system subject only to <a href="/wiki/Pressure" title="Pressure">pressure</a> forces and heat transfer (e.g., a cylinder-full of gas) without chemical changes, the differential change in the internal energy of the system (with a <i>gain</i> in energy signified by a positive quantity) is given as </p> <dl><dd><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \mathrm {d} E=T\mathrm {d} S-P\mathrm {d} V\,}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="normal">d</mi> </mrow> <mi>E</mi> <mo>=</mo> <mi>T</mi> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="normal">d</mi> </mrow> <mi>S</mi> <mo>−</mo> <mi>P</mi> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="normal">d</mi> </mrow> <mi>V</mi> <mspace width="thinmathspace" /> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \mathrm {d} E=T\mathrm {d} S-P\mathrm {d} V\,}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/01e4f87ae1402f6f7193ba9c08feaaf1edaa0fe9" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.505ex; width:18.647ex; height:2.343ex;" alt="{\displaystyle \mathrm {d} E=T\mathrm {d} S-P\mathrm {d} V\,}"></span>,</dd></dl> <p>where the first term on the right is the heat transferred into the system, expressed in terms of <a href="/wiki/Temperature" title="Temperature">temperature</a> <i>T</i> and <a href="/wiki/Entropy" title="Entropy">entropy</a> <i>S</i> (in which entropy increases and its change d<i>S</i> is positive when heat is added to the system), and the last term on the right hand side is identified as work done on the system, where pressure is <i>P</i> and volume <i>V</i> (the negative sign results since compression of the system requires work to be done on it and so the volume change, d<i>V</i>, is negative when work is done on the system). </p><p>This equation is highly specific, ignoring all chemical, electrical, nuclear, and gravitational forces, effects such as <a href="/wiki/Advection" title="Advection">advection</a> of any form of energy other than heat and <i>PV</i>-work. The general formulation of the first law (i.e., conservation of energy) is valid even in situations in which the system is not homogeneous. For these cases the change in internal energy of a <i>closed</i> system is expressed in a general form by </p> <dl><dd><span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \mathrm {d} E=\delta Q+\delta W}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="normal">d</mi> </mrow> <mi>E</mi> <mo>=</mo> <mi>δ</mi> <mi>Q</mi> <mo>+</mo> <mi>δ</mi> <mi>W</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \mathrm {d} E=\delta Q+\delta W}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/3193b93f1629c23792183555b5cd916d818d6a0a" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:15.378ex; height:2.676ex;" alt="{\displaystyle \mathrm {d} E=\delta Q+\delta W}"></span></dd></dl> <p>where <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \delta Q}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>δ</mi> <mi>Q</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \delta Q}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/bf715eece146c816847a8c5d56eae97798453d64" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.671ex; width:2.887ex; height:2.676ex;" alt="{\displaystyle \delta Q}"></span> is the heat supplied to the system and <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle \delta W}"> <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>δ</mi> <mi>W</mi> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \delta W}</annotation> </semantics> </math></span><img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/973e6b089758466f338610e76ab50fd4093efbc8" class="mwe-math-fallback-image-inline mw-invert skin-invert" aria-hidden="true" style="vertical-align: -0.338ex; width:3.484ex; height:2.343ex;" alt="{\displaystyle \delta W}"></span> is the work applied to the system. </p> <div class="mw-heading mw-heading3"><h3 id="Equipartition_of_energy">Equipartition of energy</h3></div> <p>The energy of a mechanical <a href="/wiki/Harmonic_oscillator" title="Harmonic oscillator">harmonic oscillator</a> (a mass on a spring) is alternately <a href="/wiki/Kinetic_energy" title="Kinetic energy">kinetic</a> and <a href="/wiki/Potential_energy" title="Potential energy">potential energy</a>. At two points in the oscillation <a href="/wiki/Frequency" title="Frequency">cycle</a> it is entirely kinetic, and at two points it is entirely potential. Over a whole cycle, or over many cycles, average energy is equally split between kinetic and potential. This is an example of the <a href="/wiki/Equipartition_principle" class="mw-redirect" title="Equipartition principle">equipartition principle</a>: the total energy of a system with many degrees of freedom is equally split among all available degrees of freedom, on average. </p><p>This principle is vitally important to understanding the behavior of a quantity closely related to energy, called <a href="/wiki/Entropy" title="Entropy">entropy</a>. Entropy is a measure of evenness of a <a href="/wiki/Distribution_(mathematics)" title="Distribution (mathematics)">distribution</a> of energy between parts of a system. When an isolated system is given more degrees of freedom (i.e., given new available <a href="/wiki/Energy_state" class="mw-redirect" title="Energy state">energy states</a> that are the same as existing states), then total energy spreads over all available degrees equally without distinction between "new" and "old" degrees. This mathematical result is part of the <a href="/wiki/Second_law_of_thermodynamics" title="Second law of thermodynamics">second law of thermodynamics</a>. The second law of thermodynamics is simple only for systems which are near or in a physical <a href="/wiki/Equilibrium_state" class="mw-redirect" title="Equilibrium state">equilibrium state</a>. For non-equilibrium systems, the laws governing the systems' behavior are still debatable. One of the guiding principles for these systems is the principle of <a href="/wiki/Principle_of_maximum_entropy" title="Principle of maximum entropy">maximum entropy production</a>.<sup id="cite_ref-26" class="reference"><a href="#cite_note-26"><span class="cite-bracket">[</span>21<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-27" class="reference"><a href="#cite_note-27"><span class="cite-bracket">[</span>22<span class="cite-bracket">]</span></a></sup> It states that nonequilibrium systems behave in such a way as to maximize their entropy production.<sup id="cite_ref-28" class="reference"><a href="#cite_note-28"><span class="cite-bracket">[</span>23<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="See_also">See also</h2></div> <style data-mw-deduplicate="TemplateStyles:r1239009302">.mw-parser-output .portalbox{padding:0;margin:0.5em 0;display:table;box-sizing:border-box;max-width:175px;list-style:none}.mw-parser-output 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src="//upload.wikimedia.org/wikipedia/commons/thumb/1/14/Crystal_energy.svg/29px-Crystal_energy.svg.png" decoding="async" width="29" height="28" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/1/14/Crystal_energy.svg/44px-Crystal_energy.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/1/14/Crystal_energy.svg/59px-Crystal_energy.svg.png 2x" data-file-width="130" data-file-height="124" /></a></span></span><span class="portalbox-link"><a href="/wiki/Portal:Energy" title="Portal:Energy">Energy portal</a></span></li><li class="portalbox-entry"><span class="portalbox-image"><span class="noviewer" typeof="mw:File"><a href="/wiki/File:Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg" class="mw-file-description"><img alt="icon" src="//upload.wikimedia.org/wikipedia/commons/thumb/6/6f/Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg/25px-Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg.png" decoding="async" width="25" height="28" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/6/6f/Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg/37px-Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/6/6f/Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg/49px-Stylised_atom_with_three_Bohr_model_orbits_and_stylised_nucleus.svg.png 2x" data-file-width="530" data-file-height="600" /></a></span></span><span class="portalbox-link"><a href="/wiki/Portal:Physics" title="Portal:Physics">Physics portal</a></span></li><li class="portalbox-entry"><span class="portalbox-image"><span class="noviewer" typeof="mw:File"><a href="/wiki/File:Wind-turbine-icon.svg" class="mw-file-description"><img alt="icon" src="//upload.wikimedia.org/wikipedia/commons/thumb/a/ad/Wind-turbine-icon.svg/28px-Wind-turbine-icon.svg.png" decoding="async" width="28" height="28" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/a/ad/Wind-turbine-icon.svg/42px-Wind-turbine-icon.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/a/ad/Wind-turbine-icon.svg/56px-Wind-turbine-icon.svg.png 2x" data-file-width="128" data-file-height="128" /></a></span></span><span class="portalbox-link"><a href="/wiki/Portal:Renewable_energy" title="Portal:Renewable energy">Renewable energy portal</a></span></li></ul> <style data-mw-deduplicate="TemplateStyles:r1184024115">.mw-parser-output .div-col{margin-top:0.3em;column-width:30em}.mw-parser-output .div-col-small{font-size:90%}.mw-parser-output .div-col-rules{column-rule:1px solid #aaa}.mw-parser-output .div-col dl,.mw-parser-output .div-col ol,.mw-parser-output .div-col ul{margin-top:0}.mw-parser-output .div-col li,.mw-parser-output .div-col dd{page-break-inside:avoid;break-inside:avoid-column}</style><div class="div-col"> <ul><li><a href="/wiki/Combustion" title="Combustion">Combustion</a></li> <li><a href="/wiki/Efficient_energy_use" title="Efficient energy use">Efficient energy use</a></li> <li><a href="/wiki/Energy_democracy" title="Energy democracy">Energy democracy</a></li> <li><a href="/wiki/Energy_crisis" title="Energy crisis">Energy crisis</a></li> <li><a href="/wiki/Energy_recovery" title="Energy recovery">Energy recovery</a></li> <li><a href="/wiki/Energy_recycling" title="Energy recycling">Energy recycling</a></li> <li><a href="/wiki/Index_of_energy_articles" title="Index of energy articles">Index of energy articles</a></li> <li><a href="/wiki/Index_of_wave_articles" title="Index of wave articles">Index of wave articles</a></li> <li><a href="/wiki/List_of_low-energy_building_techniques" title="List of low-energy building techniques">List of low-energy building techniques</a></li> <li><a href="/wiki/Orders_of_magnitude_(energy)" title="Orders of magnitude (energy)">Orders of magnitude (energy)</a></li> <li><a href="/wiki/Power_station" title="Power station">Power station</a></li> <li><a href="/wiki/Sustainable_energy" title="Sustainable energy">Sustainable energy</a></li> <li><a href="/wiki/Spaceflight#Transfer_energy" title="Spaceflight">Transfer energy</a></li> <li><a href="/wiki/Waste-to-energy" title="Waste-to-energy">Waste-to-energy</a></li> <li><a href="/wiki/Waste-to-energy_plant" title="Waste-to-energy plant">Waste-to-energy plant</a></li> <li><a href="/wiki/Zero-energy_building" title="Zero-energy building">Zero-energy building</a></li></ul> </div> <div style="clear:both;" class=""></div> <div class="mw-heading mw-heading2"><h2 id="Notes">Notes</h2></div> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist"> <div class="mw-references-wrap"><ol class="references"> <li id="cite_note-10"><span class="mw-cite-backlink"><b><a href="#cite_ref-10">^</a></b></span> <span class="reference-text">These examples are solely for illustration, as it is not the energy available for work which limits the performance of the athlete but the <a href="/wiki/Power_(physics)" title="Power (physics)">power</a> output (in case of a sprinter) and the <a href="/wiki/Force_(physics)" class="mw-redirect" title="Force (physics)">force</a> (in case of a weightlifter).</span> </li> <li id="cite_note-11"><span class="mw-cite-backlink"><b><a href="#cite_ref-11">^</a></b></span> <span class="reference-text"><a href="/wiki/Crystal" title="Crystal">Crystals</a> are another example of highly ordered systems that exist in nature: in this case too, the order is associated with the transfer of a large amount of heat (known as the <a href="/wiki/Lattice_energy" title="Lattice energy">lattice energy</a>) to the surroundings.</span> </li> <li id="cite_note-20"><span class="mw-cite-backlink"><b><a href="#cite_ref-20">^</a></b></span> <span class="reference-text">Although heat is "wasted" energy for a specific energy transfer (see: <a href="/wiki/Waste_heat" title="Waste heat">waste heat</a>), it can often be harnessed to do useful work in subsequent interactions. However, the maximum energy that can be "recycled" from such recovery processes is limited by the <a href="/wiki/Second_law_of_thermodynamics" title="Second law of thermodynamics">second law of thermodynamics</a>.</span> </li> <li id="cite_note-21"><span class="mw-cite-backlink"><b><a href="#cite_ref-21">^</a></b></span> <span class="reference-text">The mechanism for most macroscopic physical collisions is actually <a href="/wiki/Electromagnetism" title="Electromagnetism">electromagnetic</a>, but it is very common to simplify the interaction by ignoring the mechanism of collision and just calculate the beginning and end result.</span> </li> <li id="cite_note-23"><span class="mw-cite-backlink"><b><a href="#cite_ref-23">^</a></b></span> <span class="reference-text">There are several <a href="/wiki/First_law_of_thermodynamics#Description" title="First law of thermodynamics">sign conventions for this equation</a>. Here, the signs in this equation follow the IUPAC convention.</span> </li> </ol></div></div> <div class="mw-heading mw-heading2"><h2 id="References">References</h2></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239543626"><div class="reflist"> <div class="mw-references-wrap mw-references-columns"><ol class="references"> <li id="cite_note-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-1">^</a></b></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://energyeducation.ca/encyclopedia/Earth%27s_energy_flow">"Earth's energy flow"</a>. <i>Energy Education</i><span class="reference-accessdate">. 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Retrieved <span class="nowrap">2010-12-12</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Retrieved+on+May-29-09&rft.pub=Uic.edu&rft_id=http%3A%2F%2Fwww.uic.edu%2Faa%2Fcollege%2Fgallery400%2Fnotions%2Fhuman%2520energy.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AEnergy" class="Z3988"></span></span> </li> <li id="cite_note-9"><span class="mw-cite-backlink"><b><a href="#cite_ref-9">^</a></b></span> <span class="reference-text">Bicycle calculator – speed, weight, wattage etc. <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://bikecalculator.com/">"Bike Calculator"</a>. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20090513091201/http://bikecalculator.com/">Archived</a> from the original on 2009-05-13<span class="reference-accessdate">. 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Noether's Discovery of the Deep Connection Between Symmetries and Conservation Laws"</a>. UCLA Physics & Astronomy. Archived from <a rel="nofollow" class="external text" href="http://www.physics.ucla.edu/~cwp/articles/noether.asg/noether.html">the original</a> on 2011-05-14<span class="reference-accessdate">. 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Rosenberg, <i>Chemical Thermodynamics – Basic Concepts and Methods</i>, 7th ed., Wiley (2008), p. 39</span> </li> <li id="cite_note-KK-25"><span class="mw-cite-backlink"><b><a href="#cite_ref-KK_25-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFKittel_and_Kroemer1980" class="citation book cs1">Kittel and Kroemer (1980). <i>Thermal Physics</i>. New York: W.H. Freeman. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-7167-1088-2" title="Special:BookSources/978-0-7167-1088-2"><bdi>978-0-7167-1088-2</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Thermal+Physics&rft.place=New+York&rft.pub=W.H.+Freeman&rft.date=1980&rft.isbn=978-0-7167-1088-2&rft.au=Kittel+and+Kroemer&rfr_id=info%3Asid%2Fen.wikipedia.org%3AEnergy" class="Z3988"></span></span> </li> <li id="cite_note-26"><span class="mw-cite-backlink"><b><a href="#cite_ref-26">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFOnsager1931" class="citation journal cs1">Onsager, L. (1931). <a rel="nofollow" class="external text" href="https://doi.org/10.1103%2FPhysRev.37.405">"Reciprocal relations in irreversible processes"</a>. <i>Phys. Rev</i>. <b>37</b> (4): 405–26. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1931PhRv...37..405O">1931PhRv...37..405O</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1103%2FPhysRev.37.405">10.1103/PhysRev.37.405</a></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Phys.+Rev.&rft.atitle=Reciprocal+relations+in+irreversible+processes.&rft.volume=37&rft.issue=4&rft.pages=405-26&rft.date=1931&rft_id=info%3Adoi%2F10.1103%2FPhysRev.37.405&rft_id=info%3Abibcode%2F1931PhRv...37..405O&rft.aulast=Onsager&rft.aufirst=L.&rft_id=https%3A%2F%2Fdoi.org%2F10.1103%252FPhysRev.37.405&rfr_id=info%3Asid%2Fen.wikipedia.org%3AEnergy" class="Z3988"></span></span> </li> <li id="cite_note-27"><span class="mw-cite-backlink"><b><a href="#cite_ref-27">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMartyushevSeleznev2006" class="citation journal cs1">Martyushev, L. M.; Seleznev, V. D. (2006). "Maximum entropy production principle in physics, chemistry and biology". <i>Physics Reports</i>. <b>426</b> (1): 1–45. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2006PhR...426....1M">2006PhR...426....1M</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1016%2Fj.physrep.2005.12.001">10.1016/j.physrep.2005.12.001</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Physics+Reports&rft.atitle=Maximum+entropy+production+principle+in+physics%2C+chemistry+and+biology&rft.volume=426&rft.issue=1&rft.pages=1-45&rft.date=2006&rft_id=info%3Adoi%2F10.1016%2Fj.physrep.2005.12.001&rft_id=info%3Abibcode%2F2006PhR...426....1M&rft.aulast=Martyushev&rft.aufirst=L.+M.&rft.au=Seleznev%2C+V.+D.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AEnergy" class="Z3988"></span></span> </li> <li id="cite_note-28"><span class="mw-cite-backlink"><b><a href="#cite_ref-28">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBelkinet.2015" class="citation journal cs1">Belkin, A.; et., al. (2015). <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4321171">"Self-Assembled Wiggling Nano-Structures and the Principle of Maximum Entropy Production"</a>. <i>Sci. Rep</i>. <b>5</b>: 8323. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2015NatSR...5.8323B">2015NatSR...5.8323B</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1038%2Fsrep08323">10.1038/srep08323</a>. <a href="/wiki/PMC_(identifier)" class="mw-redirect" title="PMC (identifier)">PMC</a> <span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4321171">4321171</a></span>. <a href="/wiki/PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/25662746">25662746</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Sci.+Rep.&rft.atitle=Self-Assembled+Wiggling+Nano-Structures+and+the+Principle+of+Maximum+Entropy+Production&rft.volume=5&rft.pages=8323&rft.date=2015&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC4321171%23id-name%3DPMC&rft_id=info%3Apmid%2F25662746&rft_id=info%3Adoi%2F10.1038%2Fsrep08323&rft_id=info%3Abibcode%2F2015NatSR...5.8323B&rft.aulast=Belkin&rft.aufirst=A.&rft.au=et.%2C+al.&rft_id=https%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fpmc%2Farticles%2FPMC4321171&rfr_id=info%3Asid%2Fen.wikipedia.org%3AEnergy" class="Z3988"></span></span> </li> </ol></div></div> <div class="mw-heading mw-heading2"><h2 id="Further_reading">Further reading</h2></div> <style data-mw-deduplicate="TemplateStyles:r1239549316">.mw-parser-output .refbegin{margin-bottom:0.5em}.mw-parser-output .refbegin-hanging-indents>ul{margin-left:0}.mw-parser-output .refbegin-hanging-indents>ul>li{margin-left:0;padding-left:3.2em;text-indent:-3.2em}.mw-parser-output .refbegin-hanging-indents ul,.mw-parser-output .refbegin-hanging-indents ul li{list-style:none}@media(max-width:720px){.mw-parser-output .refbegin-hanging-indents>ul>li{padding-left:1.6em;text-indent:-1.6em}}.mw-parser-output .refbegin-columns{margin-top:0.3em}.mw-parser-output .refbegin-columns ul{margin-top:0}.mw-parser-output .refbegin-columns li{page-break-inside:avoid;break-inside:avoid-column}@media screen{.mw-parser-output .refbegin{font-size:90%}}</style><div class="refbegin" style=""> <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation book cs1">Alekseev, G. N. (1986). <a rel="nofollow" class="external text" href="https://archive.org/details/EnergyAndEntropy"><i>Energy and Entropy</i></a>. Moscow, Russia: Mir Publishers.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Energy+and+Entropy&rft.place=Moscow%2C+Russia&rft.pub=Mir+Publishers&rft.date=1986&rft.aulast=Alekseev&rft.aufirst=G.+N.&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2FEnergyAndEntropy&rfr_id=info%3Asid%2Fen.wikipedia.org%3AEnergy" class="Z3988"></span></li> <li><i>The <a href="/wiki/Biosphere" title="Biosphere">Biosphere</a></i> (A <i><a href="/wiki/Scientific_American" title="Scientific American">Scientific American</a></i> Book), San Francisco, California, W. H. Freeman and Company, 1970.<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0-7167-0945-7" title="Special:BookSources/0-7167-0945-7">0-7167-0945-7</a>. This book, originally a 1970 <i><a href="/wiki/Scientific_American" title="Scientific American">Scientific American</a></i> issue, covers virtually every major concern and concept since debated regarding materials and <a href="/wiki/Energy_resource" class="mw-redirect" title="Energy resource">energy resources</a>, <a href="/wiki/Population" title="Population">population</a> trends, and <a href="/wiki/Environmental_degradation" title="Environmental degradation">environmental degradation</a>.</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation cs1">Crowell, Benjamin (2011). <a rel="nofollow" class="external text" href="http://www.lightandmatter.com/lm">"ch. 11"</a>. <i>Light and Matter</i>. Fullerton, California: Light and Matter. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20110519093054/http://lightandmatter.com/lm/">Archived</a> from the original on 2011-05-19<span class="reference-accessdate">. Retrieved <span class="nowrap">2017-04-12</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=ch.+11&rft.btitle=Light+and+Matter&rft.place=Fullerton%2C+California&rft.pub=Light+and+Matter&rft.date=2011&rft.aulast=Crowell&rft.aufirst=Benjamin&rft_id=http%3A%2F%2Fwww.lightandmatter.com%2Flm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AEnergy" class="Z3988"></span></li> <li><i>Energy and Power</i> (A <i><a href="/wiki/Scientific_American" title="Scientific American">Scientific American</a></i> Book), San Francisco, California, W. H. Freeman and Company, 1971.<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0-7167-0938-4" title="Special:BookSources/0-7167-0938-4">0-7167-0938-4</a>.</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1">Ross, John S. (23 April 2002). <a rel="nofollow" class="external text" href="http://www.physnet.org/modules/pdf_modules/m20.pdf">"Work, Power, Kinetic Energy"</a> <span class="cs1-format">(PDF)</span>. <i>Project PHYSNET</i>. Michigan State University. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20110426160837/http://www.physnet.org/modules/pdf_modules/m20.pdf">Archived</a> <span class="cs1-format">(PDF)</span> from the original on 26 April 2011<span class="reference-accessdate">. Retrieved <span class="nowrap">10 April</span> 2009</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Project+PHYSNET&rft.atitle=Work%2C+Power%2C+Kinetic+Energy&rft.date=2002-04-23&rft.aulast=Ross&rft.aufirst=John+S.&rft_id=http%3A%2F%2Fwww.physnet.org%2Fmodules%2Fpdf_modules%2Fm20.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AEnergy" class="Z3988"></span></li> <li>Santos, Gildo M. "Energy in Brazil: a historical overview," <i>The Journal of Energy History</i> (2018), <a rel="nofollow" class="external text" href="http://www.energyhistory.eu/en/panorama/energy-brazil-historical-overview">online</a>.<a rel="nofollow" class="external text" href="https://web.archive.org/web/20190209180117/http://www.energyhistory.eu/en/panorama/energy-brazil-historical-overview">Archived</a> 2019-02-09 at the <a href="/wiki/Wayback_Machine" title="Wayback Machine">Wayback Machine</a></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation book cs1">Smil, Vaclav (2008). <i>Energy in nature and society: general energetics of complex systems</i>. Cambridge, Massachusetts: MIT Press. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-262-19565-2" title="Special:BookSources/978-0-262-19565-2"><bdi>978-0-262-19565-2</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Energy+in+nature+and+society%3A+general+energetics+of+complex+systems&rft.place=Cambridge%2C+Massachusetts&rft.pub=MIT+Press&rft.date=2008&rft.isbn=978-0-262-19565-2&rft.aulast=Smil&rft.aufirst=Vaclav&rfr_id=info%3Asid%2Fen.wikipedia.org%3AEnergy" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation book cs1">Walding, Richard; Rapkins, Greg; Rossiter, Glenn (1999). <i>New Century Senior Physics</i>. Melbourne, Australia: Oxford University Press. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-19-551084-3" title="Special:BookSources/978-0-19-551084-3"><bdi>978-0-19-551084-3</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=New+Century+Senior+Physics&rft.place=Melbourne%2C+Australia&rft.pub=Oxford+University+Press&rft.date=1999&rft.isbn=978-0-19-551084-3&rft.aulast=Walding&rft.aufirst=Richard&rft.au=Rapkins%2C+Greg&rft.au=Rossiter%2C+Glenn&rfr_id=info%3Asid%2Fen.wikipedia.org%3AEnergy" class="Z3988"></span></li></ul> </div> <div class="mw-heading mw-heading3"><h3 id="Journals">Journals</h3></div> <ul><li><a rel="nofollow" class="external text" href="http://www.energyhistory.eu/en"><i>The Journal of Energy History / Revue d'histoire de l'énergie</i> (JEHRHE), 2018– </a></li></ul> <div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2></div> <style data-mw-deduplicate="TemplateStyles:r1235681985">.mw-parser-output .side-box{margin:4px 0;box-sizing:border-box;border:1px solid #aaa;font-size:88%;line-height:1.25em;background-color:var(--background-color-interactive-subtle,#f8f9fa);display:flow-root}.mw-parser-output .side-box-abovebelow,.mw-parser-output .side-box-text{padding:0.25em 0.9em}.mw-parser-output .side-box-image{padding:2px 0 2px 0.9em;text-align:center}.mw-parser-output .side-box-imageright{padding:2px 0.9em 2px 0;text-align:center}@media(min-width:500px){.mw-parser-output .side-box-flex{display:flex;align-items:center}.mw-parser-output .side-box-text{flex:1;min-width:0}}@media(min-width:720px){.mw-parser-output .side-box{width:238px}.mw-parser-output .side-box-right{clear:right;float:right;margin-left:1em}.mw-parser-output .side-box-left{margin-right:1em}}</style><style data-mw-deduplicate="TemplateStyles:r1250146164">.mw-parser-output .sister-box 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metadata side-box-right mw-collapsible mw-collapsed sister-box sistersitebox plainlinks"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1126788409"> <div class="side-box-abovebelow" style="clear: both"> <b>Energy</b> at Wikipedia's <a href="/wiki/Wikipedia:Wikimedia_sister_projects" title="Wikipedia:Wikimedia sister projects"><span id="sister-projects">sister projects</span></a></div> <div class="side-box-flex mw-collapsible-content"> <div class="side-box-text plainlist"><ul><li><span class="sister-logo"><span class="mw-valign-middle" typeof="mw:File"><span><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/0/06/Wiktionary-logo-v2.svg/27px-Wiktionary-logo-v2.svg.png" decoding="async" width="27" height="27" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/0/06/Wiktionary-logo-v2.svg/41px-Wiktionary-logo-v2.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/0/06/Wiktionary-logo-v2.svg/54px-Wiktionary-logo-v2.svg.png 2x" data-file-width="391" data-file-height="391" /></span></span></span><span class="sister-link"><a href="https://en.wiktionary.org/wiki/Special:Search/Energy" class="extiw" title="wikt:Special:Search/Energy">Definitions</a> from Wiktionary</span></li><li><span class="sister-logo"><span class="mw-valign-middle" typeof="mw:File"><span><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/20px-Commons-logo.svg.png" decoding="async" width="20" height="27" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/30px-Commons-logo.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/40px-Commons-logo.svg.png 2x" data-file-width="1024" data-file-height="1376" /></span></span></span><span class="sister-link"><a href="https://commons.wikimedia.org/wiki/Category:Energy" class="extiw" title="c:Category:Energy">Media</a> from Commons</span></li><li><span class="sister-logo"><span class="mw-valign-middle" typeof="mw:File"><span><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/2/24/Wikinews-logo.svg/27px-Wikinews-logo.svg.png" decoding="async" width="27" height="15" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/2/24/Wikinews-logo.svg/41px-Wikinews-logo.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/2/24/Wikinews-logo.svg/54px-Wikinews-logo.svg.png 2x" data-file-width="759" data-file-height="415" /></span></span></span><span class="sister-link"><a href="https://en.wikinews.org/wiki/Category:Energy" class="extiw" title="n:Category:Energy">News</a> from Wikinews</span></li><li><span class="sister-logo"><span class="mw-valign-middle" typeof="mw:File"><span><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/f/fa/Wikiquote-logo.svg/23px-Wikiquote-logo.svg.png" decoding="async" width="23" height="27" class="mw-file-element" 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class="sister-link"><a href="https://en.wikisource.org/wiki/Special:Search/Energy" class="extiw" title="s:Special:Search/Energy">Texts</a> from Wikisource</span></li><li><span class="sister-logo"><span class="mw-valign-middle" typeof="mw:File"><span><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/f/fa/Wikibooks-logo.svg/27px-Wikibooks-logo.svg.png" decoding="async" width="27" height="27" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/f/fa/Wikibooks-logo.svg/41px-Wikibooks-logo.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/f/fa/Wikibooks-logo.svg/54px-Wikibooks-logo.svg.png 2x" data-file-width="300" data-file-height="300" /></span></span></span><span class="sister-link"><a href="https://en.wikibooks.org/wiki/Special:Search/Energy" class="extiw" title="b:Special:Search/Energy">Textbooks</a> from Wikibooks</span></li><li><span class="sister-logo"><span class="mw-valign-middle" typeof="mw:File"><span><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/0/0b/Wikiversity_logo_2017.svg/27px-Wikiversity_logo_2017.svg.png" decoding="async" width="27" height="22" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/0/0b/Wikiversity_logo_2017.svg/41px-Wikiversity_logo_2017.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/0/0b/Wikiversity_logo_2017.svg/54px-Wikiversity_logo_2017.svg.png 2x" data-file-width="626" data-file-height="512" /></span></span></span><span class="sister-link"><a href="https://en.wikiversity.org/wiki/Energy" class="extiw" title="v:Energy">Resources</a> from Wikiversity</span></li><li><span class="sister-logo"><span class="mw-valign-middle" typeof="mw:File"><span><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/f/ff/Wikidata-logo.svg/27px-Wikidata-logo.svg.png" decoding="async" width="27" height="15" class="mw-file-element" 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.navbox-image img{max-width:none!important}@media print{body.ns-0 .mw-parser-output .navbox{display:none!important}}</style></div><div role="navigation" class="navbox" aria-labelledby="Energy" style="padding:3px"><table class="nowraplinks hlist mw-collapsible mw-collapsed navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239400231"><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Energy_footer" title="Template:Energy footer"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Energy_footer" title="Template talk:Energy footer"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Energy_footer" title="Special:EditPage/Template:Energy footer"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Energy" style="font-size:114%;margin:0 4em"><a class="mw-selflink selflink">Energy</a></div></th></tr><tr><td class="navbox-abovebelow" colspan="2"><div> <ul><li><a href="/wiki/History_of_energy" title="History of energy">History</a></li> <li><a href="/wiki/Index_of_energy_articles" title="Index of energy articles">Index</a></li> <li><a href="/wiki/Outline_of_energy" title="Outline of energy">Outline</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Fundamental <br />concepts</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Conservation_of_energy" title="Conservation of energy">Conservation of energy</a></li> <li><a href="/wiki/Thermodynamics" title="Thermodynamics">Energetics</a></li> <li><a class="mw-selflink selflink">Energy</a> <ul><li><a href="/wiki/Units_of_energy" title="Units of energy">Units</a></li></ul></li> <li><a href="/wiki/Energy_condition" title="Energy condition">Energy condition</a></li> <li><a href="/wiki/Energy_level" title="Energy level">Energy level</a></li> <li><a href="/wiki/Energy_system" title="Energy system">Energy system</a></li> <li><a href="/wiki/Energy_transformation" title="Energy transformation">Energy transformation</a></li> <li><a href="/wiki/Energy_transition" title="Energy transition">Energy transition</a></li> <li><a href="/wiki/Mass" title="Mass">Mass</a> <ul><li><a href="/wiki/Negative_mass" title="Negative mass">Negative mass</a></li> <li><a href="/wiki/Mass%E2%80%93energy_equivalence" title="Mass–energy equivalence">Mass–energy equivalence</a></li></ul></li> <li><a href="/wiki/Power_(physics)" title="Power (physics)">Power</a></li> <li><a href="/wiki/Thermodynamics" title="Thermodynamics">Thermodynamics</a> <ul><li><a href="/wiki/Enthalpy" title="Enthalpy">Enthalpy</a></li> <li><a href="/wiki/Entropic_force" title="Entropic force">Entropic force</a></li> <li><a href="/wiki/Entropy" title="Entropy">Entropy</a></li> <li><a href="/wiki/Exergy" title="Exergy">Exergy</a></li> <li><a href="/wiki/Free_entropy" title="Free entropy">Free entropy</a></li> <li><a href="/wiki/Heat_capacity" title="Heat capacity">Heat capacity</a></li> <li><a href="/wiki/Heat_transfer" title="Heat transfer">Heat transfer</a></li> <li><a href="/wiki/Irreversible_process" title="Irreversible process">Irreversible process</a></li> <li><a href="/wiki/Isolated_system" title="Isolated system">Isolated system</a></li> <li><a href="/wiki/Laws_of_thermodynamics" title="Laws of thermodynamics">Laws of thermodynamics</a></li> <li><a href="/wiki/Negentropy" title="Negentropy">Negentropy</a></li> <li><a href="/wiki/Quantum_thermodynamics" title="Quantum thermodynamics">Quantum thermodynamics</a></li> <li><a href="/wiki/Thermal_equilibrium" title="Thermal equilibrium">Thermal equilibrium</a></li> <li><a href="/wiki/Thermal_reservoir" title="Thermal reservoir">Thermal reservoir</a></li> <li><a href="/wiki/Thermodynamic_equilibrium" title="Thermodynamic equilibrium">Thermodynamic equilibrium</a></li> <li><a href="/wiki/Thermodynamic_free_energy" title="Thermodynamic free energy">Thermodynamic free energy</a></li> <li><a href="/wiki/Thermodynamic_potential" title="Thermodynamic potential">Thermodynamic potential</a></li> <li><a href="/wiki/Thermodynamic_state" title="Thermodynamic state">Thermodynamic state</a></li> <li><a href="/wiki/Thermodynamic_system" title="Thermodynamic system">Thermodynamic system</a></li> <li><a href="/wiki/Thermodynamic_temperature" title="Thermodynamic temperature">Thermodynamic temperature</a></li> <li><a href="/wiki/Volume_(thermodynamics)" title="Volume (thermodynamics)">Volume (thermodynamics)</a></li> <li><a href="/wiki/Work_(physics)" title="Work (physics)">Work</a></li></ul></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Types</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Binding_energy" title="Binding energy">Binding</a> <ul><li><a href="/wiki/Nuclear_binding_energy" title="Nuclear binding energy">Nuclear</a></li></ul></li> <li><a href="/wiki/Chemical_energy" title="Chemical energy">Chemical</a></li> <li><a href="/wiki/Dark_energy" title="Dark energy">Dark</a></li> <li><a href="/wiki/Elastic_energy" title="Elastic energy">Elastic</a></li> <li><a href="/wiki/Electric_potential_energy" title="Electric potential energy">Electric potential energy</a></li> <li><a href="/wiki/Electrical_energy" title="Electrical energy">Electrical</a></li> <li><a href="/wiki/Gravitational_energy" title="Gravitational energy">Gravitational</a> <ul><li><a href="/wiki/Gravitational_binding_energy" title="Gravitational binding energy">Binding</a></li></ul></li> <li><a href="/wiki/Interatomic_potential" title="Interatomic potential">Interatomic potential</a></li> <li><a href="/wiki/Internal_energy" title="Internal energy">Internal</a></li> <li><a href="/wiki/Ionization_energy" title="Ionization energy">Ionization</a></li> <li><a href="/wiki/Kinetic_energy" title="Kinetic energy">Kinetic</a></li> <li><a href="/wiki/Magnetic_energy" title="Magnetic energy">Magnetic</a></li> <li><a href="/wiki/Mechanical_energy" title="Mechanical energy">Mechanical</a></li> <li><a href="/wiki/Negative_energy" title="Negative energy">Negative</a></li> <li><a href="/wiki/Phantom_energy" title="Phantom energy">Phantom</a></li> <li><a href="/wiki/Potential_energy" title="Potential energy">Potential</a></li> <li><a href="/wiki/Quantum_chromodynamics_binding_energy" title="Quantum chromodynamics binding energy">Quantum chromodynamics binding energy</a></li> <li><a href="/wiki/Quantum_fluctuation" title="Quantum fluctuation">Quantum fluctuation</a></li> <li><a href="/wiki/Quantum_potential" title="Quantum potential">Quantum potential</a></li> <li><a href="/wiki/Quintessence_(physics)" title="Quintessence (physics)">Quintessence</a></li> <li><a href="/wiki/Radiant_energy" title="Radiant energy">Radiant</a></li> <li><a href="/wiki/Rest_energy" class="mw-redirect" title="Rest energy">Rest</a></li> <li><a href="/wiki/Sound_energy" title="Sound energy">Sound</a></li> <li><a href="/wiki/Surface_energy" title="Surface energy">Surface</a></li> <li><a href="/wiki/Thermal_energy" title="Thermal energy">Thermal</a></li> <li><a href="/wiki/Vacuum_energy" title="Vacuum energy">Vacuum</a></li> <li><a href="/wiki/Zero-point_energy" title="Zero-point energy">Zero-point</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Energy_carrier" title="Energy carrier">Energy carriers</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Electric_battery" title="Electric battery">Battery</a></li> <li><a href="/wiki/Capacitor" title="Capacitor">Capacitor</a></li> <li><a href="/wiki/Electricity" title="Electricity">Electricity</a></li> <li><a href="/wiki/Enthalpy" title="Enthalpy">Enthalpy</a></li> <li><a href="/wiki/Fuel" title="Fuel">Fuel</a> <ul><li><a href="/wiki/Fossil_fuel" title="Fossil fuel">Fossil</a></li> <li><a href="/wiki/Fuel_oil" title="Fuel oil">Oil</a></li></ul></li> <li><a href="/wiki/Heat" title="Heat">Heat</a> <ul><li><a href="/wiki/Latent_heat" title="Latent heat">Latent heat</a></li></ul></li> <li><a href="/wiki/Hydrogen" title="Hydrogen">Hydrogen</a> <ul><li><a href="/wiki/Hydrogen_fuel" class="mw-redirect" title="Hydrogen fuel">Hydrogen fuel</a></li></ul></li> <li><a href="/wiki/Mechanical_wave" title="Mechanical wave">Mechanical wave</a></li> <li><a href="/wiki/Radiation" title="Radiation">Radiation</a></li> <li><a href="/wiki/Sound_wave" class="mw-redirect" title="Sound wave">Sound wave</a></li> <li><a href="/wiki/Work_(physics)" title="Work (physics)">Work</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Primary_energy" title="Primary energy">Primary energy</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Bioenergy" title="Bioenergy">Bioenergy</a></li> <li><a href="/wiki/Fossil_fuel" title="Fossil fuel">Fossil fuel</a> <ul><li><a href="/wiki/Coal" title="Coal">Coal</a></li> <li><a href="/wiki/Natural_gas" title="Natural gas">Natural gas</a></li> <li><a href="/wiki/Petroleum" title="Petroleum">Petroleum</a></li></ul></li> <li><a href="/wiki/Geothermal_energy" title="Geothermal energy">Geothermal</a></li> <li><a href="/wiki/Gravitational_energy" title="Gravitational energy">Gravitational</a></li> <li><a href="/wiki/Hydropower" title="Hydropower">Hydropower</a></li> <li><a href="/wiki/Marine_energy" title="Marine energy">Marine</a></li> <li><a href="/wiki/Nuclear_fuel" title="Nuclear fuel">Nuclear fuel</a> <ul><li><a href="/wiki/Natural_uranium" title="Natural uranium">Natural uranium</a></li></ul></li> <li><a href="/wiki/Radiant_energy" title="Radiant energy">Radiant</a></li> <li><a href="/wiki/Solar_energy" title="Solar energy">Solar</a></li> <li><a href="/wiki/Wind_power" title="Wind power">Wind</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Energy_system" title="Energy system">Energy system</a><br />components</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Biomass" title="Biomass">Biomass</a></li> <li><a href="/wiki/Electric_power" title="Electric power">Electric power</a></li> <li><a href="/wiki/Electricity_delivery" title="Electricity delivery">Electricity delivery</a></li> <li><a href="/wiki/Energy_engineering" title="Energy engineering">Energy engineering</a></li> <li><a href="/wiki/Fossil_fuel_power_station" title="Fossil fuel power station">Fossil fuel power station</a> <ul><li><a href="/wiki/Cogeneration" title="Cogeneration">Cogeneration</a></li> <li><a href="/wiki/Integrated_gasification_combined_cycle" title="Integrated gasification combined cycle">Integrated gasification combined cycle</a></li></ul></li> <li><a href="/wiki/Geothermal_power" title="Geothermal power">Geothermal power</a></li> <li><a href="/wiki/Hydropower" title="Hydropower">Hydropower</a> <ul><li><a href="/wiki/Hydroelectricity" title="Hydroelectricity">Hydroelectricity</a></li> <li><a href="/wiki/Tidal_power" title="Tidal power">Tidal power</a></li> <li><a href="/wiki/Wave_farm" class="mw-redirect" title="Wave farm">Wave farm</a></li></ul></li> <li><a href="/wiki/Nuclear_power" title="Nuclear power">Nuclear power</a> <ul><li><a href="/wiki/Nuclear_power_plant" title="Nuclear power plant">Nuclear power plant</a></li> <li><a href="/wiki/Radioisotope_thermoelectric_generator" title="Radioisotope thermoelectric generator">Radioisotope thermoelectric generator</a></li></ul></li> <li><a href="/wiki/Oil_refinery" title="Oil refinery">Oil refinery</a></li> <li><a href="/wiki/Solar_power" title="Solar power">Solar power</a> <ul><li><a href="/wiki/Concentrated_solar_power" title="Concentrated solar power">Concentrated solar power</a></li> <li><a href="/wiki/Photovoltaic_system" title="Photovoltaic system">Photovoltaic system</a></li></ul></li> <li><a href="/wiki/Solar_thermal_energy" title="Solar thermal energy">Solar thermal energy</a> <ul><li><a href="/wiki/Solar_furnace" title="Solar furnace">Solar furnace</a></li> <li><a href="/wiki/Solar_power_tower" title="Solar power tower">Solar power tower</a></li></ul></li> <li><a href="/wiki/Wind_power" title="Wind power">Wind power</a> <ul><li><a href="/wiki/Airborne_wind_energy" title="Airborne wind energy">Airborne wind energy</a></li> <li><a href="/wiki/Wind_farm" title="Wind farm">Wind farm</a></li></ul></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Use and<br /><a href="/wiki/Energy_supply" title="Energy supply">supply</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Efficient_energy_use" title="Efficient energy use">Efficient energy use</a> <ul><li><a href="/wiki/Energy_efficiency_in_agriculture" title="Energy efficiency in agriculture">Agriculture</a></li> <li><a href="/wiki/Power_usage_effectiveness" title="Power usage effectiveness">Computing</a></li> <li><a href="/wiki/Energy_efficiency_in_transport" title="Energy efficiency in transport">Transport</a></li></ul></li> <li><a href="/wiki/Energy_conservation" title="Energy conservation">Energy conservation</a></li> <li><a href="/wiki/Energy_consumption" title="Energy consumption">Energy consumption</a></li> <li><a href="/wiki/Energy_policy" title="Energy policy">Energy policy</a> <ul><li><a href="/wiki/Energy_development" title="Energy development">Energy development</a></li></ul></li> <li><a href="/wiki/Energy_security" title="Energy security">Energy security</a></li> <li><a href="/wiki/Energy_storage" title="Energy storage">Energy storage</a></li> <li><a href="/wiki/Renewable_energy" title="Renewable energy">Renewable energy</a></li> <li><a href="/wiki/Sustainable_energy" title="Sustainable energy">Sustainable energy</a></li> <li><a href="/wiki/World_energy_supply_and_consumption" title="World energy supply and consumption">World energy supply and consumption</a></li> <li><a href="/wiki/Energy_in_Africa" title="Energy in Africa">Africa</a></li> <li><a href="/wiki/Energy_in_Asia" class="mw-redirect" title="Energy in Asia">Asia</a></li> <li><a href="/wiki/Energy_in_Australia" title="Energy in Australia">Australia</a></li> <li><a href="/wiki/Energy_policy_of_Canada" title="Energy policy of Canada">Canada</a></li> <li><a href="/wiki/Energy_in_Europe" title="Energy in Europe">Europe</a></li> <li><a href="/wiki/Energy_in_Mexico" title="Energy in Mexico">Mexico</a></li> <li><a href="/wiki/Energy_in_South_America" title="Energy in South America">South America</a></li> <li><a href="/wiki/Energy_in_the_United_States" title="Energy in the United States">United States</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Misc.</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Carbon_footprint" title="Carbon footprint">Carbon footprint</a></li> <li><a href="/wiki/Energy_democracy" title="Energy democracy">Energy democracy</a></li> <li><a href="/wiki/Energy_recovery" title="Energy recovery">Energy recovery</a></li> <li><a href="/wiki/Energy_recycling" title="Energy recycling">Energy recycling</a></li> <li><a href="/wiki/Jevons_paradox" title="Jevons paradox">Jevons paradox</a></li> <li><a href="/wiki/Waste-to-energy" title="Waste-to-energy">Waste-to-energy</a> <ul><li><a href="/wiki/Waste-to-energy_plant" title="Waste-to-energy plant">Waste-to-energy plant</a></li></ul></li></ul> </div></td></tr><tr><td class="navbox-abovebelow" colspan="2"><div> <ul><li><span class="noviewer" typeof="mw:File"><span title="Category"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/16px-Symbol_category_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/23px-Symbol_category_class.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/31px-Symbol_category_class.svg.png 2x" data-file-width="180" data-file-height="185" /></span></span> <b><a href="/wiki/Category:Energy" title="Category:Energy">Category</a></b></li> <li><span class="noviewer" typeof="mw:File"><span title="Commons page"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/12px-Commons-logo.svg.png" decoding="async" width="12" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/18px-Commons-logo.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/24px-Commons-logo.svg.png 2x" data-file-width="1024" data-file-height="1376" /></span></span> <b><a href="https://commons.wikimedia.org/wiki/Category:Energy" class="extiw" title="commons:Category:Energy">Commons</a></b></li> <li><span class="noviewer" typeof="mw:File"><a href="/wiki/File:Symbol_portal_class.svg" class="mw-file-description" title="Portal"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/e/e2/Symbol_portal_class.svg/16px-Symbol_portal_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/e/e2/Symbol_portal_class.svg/23px-Symbol_portal_class.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/e/e2/Symbol_portal_class.svg/31px-Symbol_portal_class.svg.png 2x" data-file-width="180" data-file-height="185" /></a></span> <b><a href="/wiki/Portal:Energy" title="Portal:Energy">Portal</a></b></li> <li><span class="noviewer" typeof="mw:File"><span title="WikiProject"><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/3/37/People_icon.svg/16px-People_icon.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/3/37/People_icon.svg/24px-People_icon.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/3/37/People_icon.svg/32px-People_icon.svg.png 2x" data-file-width="100" data-file-height="100" /></span></span> <b><a href="/wiki/Wikipedia:WikiProject_Energy" title="Wikipedia:WikiProject Energy">WikiProject</a></b></li></ul> </div></td></tr></tbody></table></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235"></div><div role="navigation" class="navbox" aria-labelledby="Elements_of_nature" style="padding:3px"><table class="nowraplinks hlist mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239400231"><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Nature" title="Template:Nature"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Nature" title="Template talk:Nature"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Nature" title="Special:EditPage/Template:Nature"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Elements_of_nature" style="font-size:114%;margin:0 4em">Elements of <a href="/wiki/Nature" title="Nature">nature</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Universe" title="Universe">Universe</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Space" title="Space">Space</a></li> <li><a href="/wiki/Time" title="Time">Time</a></li> <li><a class="mw-selflink selflink">Energy</a></li> <li><a href="/wiki/Matter" title="Matter">Matter</a> <ul><li><a href="/wiki/Particle" title="Particle">particles</a></li> <li><a href="/wiki/Chemical_element" title="Chemical element">chemical elements</a></li></ul></li> <li><a href="/wiki/Calculus" title="Calculus">Change</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Earth" title="Earth">Earth</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Earth_science" title="Earth science">Earth science</a></li> <li><a href="/wiki/History_of_Earth" title="History of Earth">History</a> (<a href="/wiki/Geological_history_of_Earth" title="Geological history of Earth">geological</a>)</li> <li><a href="/wiki/Internal_structure_of_Earth" title="Internal structure of Earth">Structure</a></li> <li><a href="/wiki/Geology" title="Geology">Geology</a></li> <li><a href="/wiki/Plate_tectonics" title="Plate tectonics">Plate tectonics</a></li> <li><a href="/wiki/Ocean" title="Ocean">Oceans</a></li> <li><a href="/wiki/Gaia_hypothesis" title="Gaia hypothesis">Gaia hypothesis</a></li> <li><a href="/wiki/Future_of_Earth" title="Future of Earth">Future</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Weather" title="Weather">Weather</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Meteorology" title="Meteorology">Meteorology</a></li> <li><a href="/wiki/Atmosphere_of_Earth" title="Atmosphere of Earth">Atmosphere <span style="font-size:85%;">(Earth)</span></a></li> <li><a href="/wiki/Climate" title="Climate">Climate</a></li> <li><a href="/wiki/Cloud" title="Cloud">Clouds</a></li> <li><a href="/wiki/Moonlight" title="Moonlight">Moonlight</a></li> <li><a href="/wiki/Rain" title="Rain">Rain</a></li> <li><a href="/wiki/Snow" title="Snow">Snow</a></li> <li><a href="/wiki/Sunlight" title="Sunlight">Sunlight</a></li> <li><a href="/wiki/Tide" title="Tide">Tides</a></li> <li><a href="/wiki/Wind" title="Wind">Wind</a> <ul><li><a href="/wiki/Tornado" title="Tornado">tornado</a></li> <li><a href="/wiki/Tropical_cyclone" title="Tropical cyclone">tropical cyclone</a></li></ul></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Natural_environment" title="Natural environment">Natural environment</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Ecology" title="Ecology">Ecology</a></li> <li><a href="/wiki/Ecosystem" title="Ecosystem">Ecosystem</a></li> <li><a href="/wiki/Field_(physics)" title="Field (physics)">Field</a></li> <li><a href="/wiki/Radiation" title="Radiation">Radiation</a></li> <li><a href="/wiki/Wilderness" title="Wilderness">Wilderness</a></li> <li><a href="/wiki/Wildfire" title="Wildfire">Wildfires</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Life" title="Life">Life</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><td colspan="2" class="navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Abiogenesis" title="Abiogenesis">Origin <span style="font-size:85%;">(abiogenesis)</span></a></li> <li><a href="/wiki/History_of_life" title="History of life">Evolutionary history</a></li> <li><a href="/wiki/Biosphere" title="Biosphere">Biosphere</a></li> <li><a href="/wiki/Biological_organisation" title="Biological organisation">Hierarchy</a></li> <li><a href="/wiki/Biology" title="Biology">Biology</a> (<a href="/wiki/Astrobiology" title="Astrobiology">astrobiology</a>)</li></ul> </div></td></tr><tr><td colspan="2" class="navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Biodiversity" title="Biodiversity">Biodiversity</a></li> <li><a href="/wiki/Organism" title="Organism">Organism</a></li> <li><a href="/wiki/Eukaryote" title="Eukaryote">Eukaryota</a> <ul><li><a href="/wiki/Flora" title="Flora">flora</a> <ul><li><a href="/wiki/Plant" title="Plant">plants</a></li></ul></li> <li><a href="/wiki/Fauna" title="Fauna">fauna</a> <ul><li><a href="/wiki/Animal" title="Animal">animals</a></li></ul></li> <li><a href="/wiki/Fungus" title="Fungus">fungi</a></li> <li><a href="/wiki/Protist" title="Protist">protista</a></li></ul></li> <li><a href="/wiki/Prokaryote" title="Prokaryote">Prokaryotes</a> <ul><li><a href="/wiki/Archaea" title="Archaea">archaea</a></li> <li><a href="/wiki/Bacteria" title="Bacteria">bacteria</a></li></ul></li> <li><i><a href="/wiki/Virus" title="Virus">Viruses</a></i></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">See also</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Nature-based_solutions" title="Nature-based solutions">Nature-based solutions</a></li></ul> </div></td></tr><tr><td class="navbox-abovebelow" colspan="2"><div> <ul><li><span class="noviewer" typeof="mw:File"><span title="Category"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/16px-Symbol_category_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/23px-Symbol_category_class.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/31px-Symbol_category_class.svg.png 2x" data-file-width="180" data-file-height="185" /></span></span> <a href="/wiki/Category:Nature" title="Category:Nature">Category</a></li></ul> </div></td></tr></tbody></table></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235"></div><div role="navigation" class="navbox" aria-labelledby="Natural_resources" style="padding:3px"><table class="nowraplinks hlist mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239400231"><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Natural_resources" title="Template:Natural resources"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Natural_resources" title="Template talk:Natural resources"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Natural_resources" title="Special:EditPage/Template:Natural resources"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Natural_resources" style="font-size:114%;margin:0 4em"><a href="/wiki/Natural_resource" title="Natural resource">Natural resources</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Atmosphere_of_Earth" title="Atmosphere of Earth">Air</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:7.0em;font-weight:normal;"><a href="/wiki/Air_pollution" title="Air pollution">Pollution / quality</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/National_Ambient_Air_Quality_Standards" title="National Ambient Air Quality Standards">Ambient standards <span style="font-size:85%;">(US)</span></a></li> <li><a href="/wiki/Air_quality_index" title="Air quality index">Index</a></li> <li><a href="/wiki/Indoor_air_quality" title="Indoor air quality">Indoor</a></li> <li><a href="/wiki/Air_quality_law" title="Air quality law">Law</a> <ul><li><a href="/wiki/Clean_Air_Act_(United_States)" title="Clean Air Act (United States)">Clean Air Act <span style="font-size:85%;">(US)</span></a></li></ul></li> <li><a href="/wiki/Ozone_depletion" title="Ozone depletion">Ozone depletion</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:7.0em;font-weight:normal;">Emissions</th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Airshed" title="Airshed">Airshed</a></li> <li><a href="/wiki/Emissions_trading" title="Emissions trading">Trading</a></li> <li><a href="/wiki/Reducing_emissions_from_deforestation_and_forest_degradation" class="mw-redirect" title="Reducing emissions from deforestation and forest degradation">Deforestation (REDD)</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a class="mw-selflink selflink">Energy</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Bioenergy" title="Bioenergy">Bio</a></li> <li><a href="/wiki/Energy_law" title="Energy law">Law</a></li> <li><a href="/wiki/Energy_resources" class="mw-redirect" title="Energy resources">Resources</a></li> <li><a href="/wiki/Fossil_fuel" title="Fossil fuel">Fossil fuels</a> (<a href="/wiki/Fuel_gas" title="Fuel gas">gas</a>, <a href="/wiki/Peak_coal" title="Peak coal">peak coal</a>, <a href="/wiki/Peak_gas" title="Peak gas">peak gas</a>, <a href="/wiki/Peak_oil" title="Peak oil">peak oil</a>)</li> <li><a href="/wiki/Geothermal_energy" title="Geothermal energy">Geothermal</a></li> <li><a href="/wiki/Hydropower" title="Hydropower">Hydro</a></li> <li><a href="/wiki/Nuclear_power" title="Nuclear power">Nuclear</a></li> <li><a href="/wiki/Solar_energy" title="Solar energy">Solar</a> <ul><li><a href="/wiki/Sunlight" title="Sunlight">sunlight</a></li> <li><a href="/wiki/Shade_(shadow)" title="Shade (shadow)">shade</a></li></ul></li> <li><a href="/wiki/Wind_power" title="Wind power">Wind</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Land" title="Land">Land</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Agricultural_land" title="Agricultural land">Agricultural</a> <ul><li><a href="/wiki/Arable_land" title="Arable land">arable</a> <ul><li><a href="/wiki/Peak_farmland" title="Peak farmland">peak farmland</a></li></ul></li></ul></li> <li><a href="/wiki/Land_degradation" title="Land degradation">Degradation</a></li> <li><a href="/wiki/Field_(agriculture)" title="Field (agriculture)">Field</a></li> <li><a href="/wiki/Landscape" title="Landscape">Landscape</a> <ul><li><a href="/wiki/Cityscape" title="Cityscape">cityscape</a></li> <li><a href="/wiki/Seascape" title="Seascape">seascape</a></li> <li><a href="/wiki/Soundscape" title="Soundscape">soundscape</a></li> <li><a href="/wiki/Viewshed" title="Viewshed">viewshed</a></li></ul></li> <li><a href="/wiki/Land_law" title="Land law">Law</a> <ul><li><a href="/wiki/Property_law" title="Property law">property</a></li></ul></li> <li><a href="/wiki/Land_management" title="Land management">Management</a> <ul><li><a href="/wiki/Habitat_conservation" title="Habitat conservation">habitat conservation</a></li></ul></li> <li><a href="/wiki/Mineral" title="Mineral">Minerals</a> <ul><li><a href="/wiki/Gemstone" title="Gemstone">gemstone</a></li> <li><a href="/wiki/Industrial_mineral" title="Industrial mineral">industrial</a></li> <li><a href="/wiki/Ore" title="Ore">ore</a> <ul><li><a href="/wiki/Metal" title="Metal">metal</a></li></ul></li> <li><a href="/wiki/Mining" title="Mining">mining</a> <ul><li><a href="/wiki/Mining_law" title="Mining law">law</a></li> <li><a href="/wiki/Sand_mining" title="Sand mining">sand</a></li></ul></li> <li><a href="/wiki/Peak_minerals" title="Peak minerals">peak</a> <ul><li><a href="/wiki/Peak_copper" class="mw-redirect" title="Peak copper">copper</a></li> <li><a href="/wiki/Peak_phosphorus" class="mw-redirect" title="Peak phosphorus">phosphorus</a></li></ul></li> <li><a href="/wiki/Mineral_rights" title="Mineral rights">rights</a></li></ul></li> <li><a href="/wiki/Soil" title="Soil">Soil</a> <ul><li><a href="/wiki/Soil_conservation" title="Soil conservation">conservation</a></li> <li><a href="/wiki/Soil_fertility" title="Soil fertility">fertility</a></li> <li><a href="/wiki/Soil_health" title="Soil health">health</a></li> <li><a href="/wiki/Soil_resilience" title="Soil resilience">resilience</a></li></ul></li> <li><a href="/wiki/Land_use" title="Land use">Use</a> <ul><li><a href="/wiki/Land-use_planning" title="Land-use planning">planning</a></li> <li><a href="/wiki/Open_space_reserve" title="Open space reserve">reserve</a></li></ul></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Life" title="Life">Life</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Biodiversity" title="Biodiversity">Biodiversity</a></li> <li><a href="/wiki/Bioprospecting" title="Bioprospecting">Bioprospecting</a> <ul><li><a href="/wiki/Biopiracy" title="Biopiracy">biopiracy</a></li></ul></li> <li><a href="/wiki/Biosphere" title="Biosphere">Biosphere</a></li> <li><a href="/wiki/Bushfood" class="mw-redirect" title="Bushfood">Bushfood</a></li> <li><a href="/wiki/Bushmeat" title="Bushmeat">Bushmeat</a></li> <li><a href="/wiki/Fishery" title="Fishery">Fisheries</a> <ul><li><a href="/wiki/Climate_change_and_fisheries" title="Climate change and fisheries">climate change</a></li> <li><a href="/wiki/Fisheries_law" title="Fisheries law">law</a></li> <li><a href="/wiki/Fisheries_management" title="Fisheries management">management</a></li></ul></li> <li><a href="/wiki/Forest" title="Forest">Forests</a> <ul><li><a href="/wiki/Forest_genetic_resources" title="Forest genetic resources">genetic resources</a></li> <li><a href="/wiki/Forestry_law" title="Forestry law">law</a></li> <li><a href="/wiki/Forest_management" title="Forest management">management</a></li> <li><a href="/wiki/Non-timber_forest_product" title="Non-timber forest product">non-timber products</a></li></ul></li> <li><a href="/wiki/Game_(food)" class="mw-redirect" title="Game (food)">Game</a> <ul><li><a href="/wiki/Game_law" title="Game law">law</a></li></ul></li> <li><a href="/wiki/Marine_conservation" title="Marine conservation">Marine conservation</a></li> <li><a href="/wiki/Meadow" title="Meadow">Meadow</a></li> <li><a href="/wiki/Pasture" title="Pasture">Pasture</a></li> <li><a href="/wiki/Plant" title="Plant">Plants</a> <ul><li><a href="/wiki/Plant_Treaty" class="mw-redirect" title="Plant Treaty">FAO Plant Treaty</a></li> <li><a href="/wiki/Food" title="Food">food</a></li> <li><a href="/wiki/Plant_genetic_resources" title="Plant genetic resources">genetic resources</a></li> <li><a href="/wiki/Gene_bank" title="Gene bank">gene banks</a></li> <li><a href="/wiki/List_of_plants_used_in_herbalism" title="List of plants used in herbalism">herbal medicines</a></li> <li><a href="/wiki/UPOV" class="mw-redirect" title="UPOV">UPOV Convention</a></li> <li><a href="/wiki/Wood" title="Wood">wood</a></li></ul></li> <li><a href="/wiki/Rangeland" title="Rangeland">Rangeland</a></li> <li><a href="/wiki/Seed_bank" title="Seed bank">Seed bank</a></li> <li><a href="/wiki/Wildlife" title="Wildlife">Wildlife</a> <ul><li><a href="/wiki/Wildlife_conservation" title="Wildlife conservation">conservation</a></li> <li><a href="/wiki/Wildlife_management" title="Wildlife management">management</a></li></ul></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Water" title="Water">Water</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:7.0em;font-weight:normal;">Types / location</th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Aquifer" title="Aquifer">Aquifer</a> <ul><li><a href="/wiki/Aquifer_storage_and_recovery" title="Aquifer storage and recovery">storage and recovery</a></li></ul></li> <li><a href="/wiki/Drinking_water" title="Drinking water">Drinking</a></li> <li><a href="/wiki/Fresh_water" title="Fresh water">Fresh</a></li> <li><a href="/wiki/Groundwater" title="Groundwater">Groundwater</a> <ul><li><a href="/wiki/Groundwater_pollution" title="Groundwater pollution">pollution</a></li> <li><a href="/wiki/Groundwater_recharge" title="Groundwater recharge">recharge</a></li> <li><a href="/wiki/Groundwater_remediation" title="Groundwater remediation">remediation</a></li></ul></li> <li><a href="/wiki/Hydrosphere" title="Hydrosphere">Hydrosphere</a></li> <li><a href="/wiki/Ice" title="Ice">Ice</a> <ul><li><a href="/wiki/Iceberg" title="Iceberg">bergs</a></li> <li><a href="/wiki/Glacier" title="Glacier">glacial</a></li> <li><a href="/wiki/Polar_ice_cap" title="Polar ice cap">polar</a></li></ul></li> <li><a href="/wiki/Irrigation" title="Irrigation">Irrigation</a> <ul><li><i><a href="/wiki/Huerta" title="Huerta">huerta</a></i></li></ul></li> <li><a href="/wiki/Marine_resources" title="Marine resources">Marine</a></li> <li><a href="/wiki/Rain" title="Rain">Rain</a> <ul><li><a href="/wiki/Rainwater_harvesting" title="Rainwater harvesting">harvesting</a></li></ul></li> <li><a href="/wiki/Stormwater" title="Stormwater">Stormwater</a></li> <li><a href="/wiki/Surface_water" title="Surface water">Surface water</a></li> <li><a href="/wiki/Sewage" title="Sewage">Sewage</a> <ul><li><a href="/wiki/Reclaimed_water" title="Reclaimed water">reclaimed water</a></li></ul></li> <li><a href="/wiki/Drainage_basin" title="Drainage basin">Watershed</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:7.0em;font-weight:normal;">Aspects</th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Desalination" title="Desalination">Desalination</a></li> <li><a href="/wiki/Flood" title="Flood">Floods</a></li> <li><a href="/wiki/Water_law" class="mw-redirect" title="Water law">Law</a></li> <li><a href="/wiki/Leaching_(agriculture)" title="Leaching (agriculture)">Leaching</a></li> <li><a href="/wiki/Sanitation" title="Sanitation">Sanitation</a> <ul><li><a href="/wiki/Improved_sanitation" title="Improved sanitation">improved</a></li></ul></li> <li><a href="/wiki/Water_scarcity" title="Water scarcity">Scarcity</a></li> <li><a href="/wiki/Water_security" title="Water security">Security</a></li> <li><a href="/wiki/Water_supply" title="Water supply">Supply</a></li> <li><a href="/wiki/Water_efficiency" title="Water efficiency">Efficiency</a></li> <li><a href="/wiki/Water_conflict" title="Water conflict">Conflict</a></li> <li><a href="/wiki/Water_conservation" title="Water conservation">Conservation</a></li> <li><a href="/wiki/Peak_water" title="Peak water">Peak water</a></li> <li><a href="/wiki/Water_pollution" title="Water pollution">Pollution</a></li> <li><a href="/wiki/Water_privatization" title="Water privatization">Privatization</a></li> <li><a href="/wiki/Water_quality" title="Water quality">Quality</a></li> <li><a href="/wiki/Water_right" title="Water right">Right</a></li> <li><a href="/wiki/Water_resources" title="Water resources">Resources</a> <ul><li><a href="/wiki/Improved_water_source" title="Improved water source">improved</a></li> <li><a href="/wiki/Water_resource_policy" title="Water resource policy">policy</a></li></ul></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Related</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><td colspan="2" class="navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Commons" title="Commons">Commons</a> <ul><li><a href="/wiki/Enclosure" title="Enclosure">enclosure</a></li> <li><a href="/wiki/Global_commons" title="Global commons">global</a></li> <li><a href="/wiki/Common_land" title="Common land">land</a></li> <li><a href="/wiki/Tragedy_of_the_commons" title="Tragedy of the commons">tragedy of</a></li></ul></li> <li><a href="/wiki/Natural_resource_economics" title="Natural resource economics">Economics</a> <ul><li><a href="/wiki/Ecological_economics" title="Ecological economics">ecological</a></li> <li><a href="/wiki/Land_(economics)" title="Land (economics)">land</a></li></ul></li> <li><a href="/wiki/Ecosystem_services" class="mw-redirect" title="Ecosystem services">Ecosystem services</a></li> <li><a href="/wiki/Exploitation_of_natural_resources" title="Exploitation of natural resources">Exploitation</a> <ul><li><a href="/wiki/Overexploitation" title="Overexploitation">overexploitation</a></li> <li><a href="/wiki/Earth_Overshoot_Day" title="Earth Overshoot Day">Earth Overshoot Day</a></li></ul></li> <li><a href="/wiki/Natural_resource_management" title="Natural resource management">Management</a> <ul><li><a href="/wiki/Adaptive_management" title="Adaptive management">adaptive</a></li></ul></li> <li><a href="/wiki/Natural_capital" title="Natural capital">Natural capital</a> <ul><li><a href="/wiki/Natural_capital_accounting" title="Natural capital accounting">accounting</a></li> <li><a href="/wiki/Environmental_good" title="Environmental good">good</a></li></ul></li> <li><a href="/wiki/Natural_heritage" title="Natural heritage">Natural heritage</a></li> <li><a href="/wiki/Nature_reserve" title="Nature reserve">Nature reserve</a> <ul><li><a href="/wiki/Remnant_natural_area" title="Remnant natural area">remnant natural area</a></li></ul></li> <li><a href="/wiki/Systems_ecology" title="Systems ecology">Systems ecology</a></li> <li><a href="/wiki/Urban_ecology" title="Urban ecology">Urban ecology</a></li> <li><a href="/wiki/Wilderness" title="Wilderness">Wilderness</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:7.0em;font-weight:normal;"><a href="/wiki/Resource" title="Resource">Resource</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Common-pool_resource" title="Common-pool resource">Common-pool</a></li> <li><a href="/wiki/Conflict_resource" class="mw-redirect" title="Conflict resource">Conflict <span style="font-size:85%;">(perpetuation)</span></a></li> <li><a href="/wiki/Resource_curse" title="Resource curse">Curse</a></li> <li><a href="/wiki/Resource_depletion" title="Resource depletion">Depletion</a></li> <li><a href="/wiki/Resource_extraction" class="mw-redirect" title="Resource extraction">Extraction</a></li> <li><a href="/wiki/Resource_nationalism" title="Resource nationalism">Nationalism</a></li> <li><a href="/wiki/Renewable_resource" title="Renewable resource">Renewable</a> / <a href="/wiki/Non-renewable_resource" title="Non-renewable resource">Non-renewable</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><td class="navbox-abovebelow" colspan="2"><div> <ul><li><span class="noviewer" 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