{"id":179889,"date":"2016-02-11T03:00:00","date_gmt":"2016-02-11T00:00:00","guid":{"rendered":"http:\/\/www.fyysika.ee\/?guid=9e13077d20c23e6f2a362afe723e56fe"},"modified":"2016-02-11T03:00:00","modified_gmt":"2016-02-11T00:00:00","slug":"investigating-the-mpemba-effect-when-hot-water-freezes-faster-than-cold-water","status":"publish","type":"post","link":"https:\/\/www.fyysika.ee\/?p=179889","title":{"rendered":"Investigating the Mpemba Effect: when hot water freezes faster than cold water"},"content":{"rendered":"<p>Under certain conditions a body of hot liquid may cool faster and freeze before a body of colder<br \/>\nliquid, a phenomenon known as the Mpemba Effect. An initial difference in temperature of 3.2 \u00b0C<br \/>\nenabled warmer water to reach 0 \u00b0C in 14% less time than colder water. Convection currents in the<br \/>\nliquid generate a temperature gradient that causes more rapid heat loss by surface radiation and<br \/>\nevaporation than obtains for uniform temperature. This more rapid cooling enables the initially<br \/>\nwarmer liquid to overtake the cooler liquid, reaching 0 \u00b0C earlier and freezing first. Liquid<br \/>\ncooling under natural convection follows a five-fourths power law (temperature of liquid ##IMG##<br \/>\n[http:\/\/ej.iop.org\/images\/0031-9120\/51\/2\/025011\/pedaa0af1ieqn001.gif] {$T$} , temperature of<br \/>\nsurroundings ##IMG## [http:\/\/ej.iop.org\/images\/0031-9120\/51\/2\/025011\/pedaa0af1ieqn002.gif]<br \/>\n{${{T}_{a}}$} , cooling constant ##IMG## [http:\/\/ej.iop&#8230;.] {$k$}<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Under certain conditions a body of hot liquid may cool faster and freeze before a body of colder<br \/>\nliquid, a phenomenon known as the Mpemba Effect. An initial difference in temperature of 3.2 \u00b0C<br \/>\nenabled warmer water to reach 0 \u00b0C in 14% less time tha&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_genesis_hide_title":false,"_genesis_hide_breadcrumbs":false,"_genesis_hide_singular_image":false,"_genesis_hide_footer_widgets":false,"_genesis_custom_body_class":"","_genesis_custom_post_class":"","_genesis_layout":"","footnotes":""},"categories":[178],"tags":[],"class_list":{"0":"post-179889","1":"post","2":"type-post","3":"status-publish","4":"format-standard","6":"category-rss-fuusikaharidus","7":"entry"},"_links":{"self":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/posts\/179889","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=179889"}],"version-history":[{"count":0,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/posts\/179889\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=179889"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=179889"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=179889"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}