{"id":440460,"date":"2017-08-17T02:00:00","date_gmt":"2017-08-16T23:00:00","guid":{"rendered":"http:\/\/www.fyysika.ee\/?guid=caee3c740c26de4307ca72e6f51bdd53"},"modified":"2017-08-17T02:00:00","modified_gmt":"2017-08-16T23:00:00","slug":"a-quantitative-experiment-on-the-fountain-effect-in-superfluid-helium","status":"publish","type":"post","link":"https:\/\/www.fyysika.ee\/?p=440460","title":{"rendered":"A quantitative experiment on the fountain effect in superfluid helium"},"content":{"rendered":"<p>Superfluid helium, a state of matter existing at low temperatures, shows many remarkable properties.<br \/>\nOne example is the so called fountain effect, where a heater can produce a jet of helium. This<br \/>\nconverts heat into mechanical motion; a machine with no moving parts, but working only below 2 K.<br \/>\nAllen and Jones first demonstrated the effect in 1938, but their work was basically qualitative. We<br \/>\nnow present data of a quantitative version of the experiment. We have measured the heat supplied,<br \/>\nthe temperature and the height of the jet produced. We also develop equations, based on the<br \/>\ntwo-fluid model of superfluid helium, that give a satisfactory fit to the data. The experiment has<br \/>\nbeen performed by advanced undergraduate students in our home institution, and illustrates in a<br \/>\nvivid way some of the striking properties of the superfluid state.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Superfluid helium, a state of matter existing at low temperatures, shows many remarkable properties.<br \/>\nOne example is the so called fountain effect, where a heater can produce a jet of helium. This<br \/>\nconverts heat into mechanical motion; a machine with n&#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-440460","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\/440460","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=440460"}],"version-history":[{"count":0,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/posts\/440460\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=440460"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=440460"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=440460"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}