{"id":12976,"date":"2013-01-16T03:00:07","date_gmt":"2013-01-16T08:00:07","guid":{"rendered":"http:\/\/blogs.scienceforums.net\/swansont\/?p=12976"},"modified":"2013-01-16T03:00:07","modified_gmt":"2013-01-16T08:00:07","slug":"12976","status":"publish","type":"post","link":"http:\/\/blogs.scienceforums.net\/swansont\/archives\/12976","title":{"rendered":"Uncertain if This is Just Diffraction"},"content":{"rendered":"<p><object class=\"embed\" width=\"425\" height=\"264\" type=\"application\/x-shockwave-flash\" \ndata=\"http:\/\/www.youtube.com\/v\/a8FTr2qMutA?fs=1\"><param name=\"wmode\" value=\"transparent\" \/><param name=\"movie\" value=\"http:\/\/www.youtube.com\/v\/a8FTr2qMutA?fs=1\" \/><em>You need to a flashplayer enabled browser to view this YouTube video<\/em><\/object><\/p>\n<p><a href=\"http:\/\/physicsandphysicists.blogspot.com\/2013\/01\/misconception-of-heisenberg-uncertainty.html\">via zapperz<\/a><\/p>\n<p>One thing that would have been useful, I think, is a calculation in support of this, even if it&#8217;s just an order-of-magnitude one, to tell us if this is reasonable.  The size of the spot (maybe a cm?) gives you a bound on the uncertainty of the transverse momentum.  It&#8217;s green light (probably 532 nm) and the screen is of order a meter behind the slit.  That tells us what the transverse component of the momentum should be \u2014 the momentum of the photon multiplied by the sine of the angle (or just the angle, in the small-angle approximation, which is around 0.01 radians)<\/p>\n<p>So the uncertainty of the momentum is around 0.01 of the momentum, given by \\(h\/lambda\\), so Planck&#8217;s constant drops out when we pop this into the uncertainty relation.  Rearranging the equation tells us that $latexDelta{x} &gt; frac{lambda}{4pitheta}$ or that we shouldn&#8217;t see this effect until the slits are separated by less than about 10x the wavelength of the light \u2014 which is around what we expect just from experience in diffracting light, that it only becomes an important consideration as you approach the wavelength of the light.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>You need to a flashplayer enabled browser to view this YouTube video via zapperz One thing that would have been useful, I think, is a calculation in support of this, even if it&#8217;s just an order-of-magnitude one, to tell us &hellip; <a href=\"http:\/\/blogs.scienceforums.net\/swansont\/archives\/12976\">Continue reading <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[39],"tags":[],"class_list":["post-12976","post","type-post","status-publish","format-standard","hentry","category-physics"],"_links":{"self":[{"href":"http:\/\/blogs.scienceforums.net\/swansont\/wp-json\/wp\/v2\/posts\/12976","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/blogs.scienceforums.net\/swansont\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/blogs.scienceforums.net\/swansont\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/blogs.scienceforums.net\/swansont\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"http:\/\/blogs.scienceforums.net\/swansont\/wp-json\/wp\/v2\/comments?post=12976"}],"version-history":[{"count":0,"href":"http:\/\/blogs.scienceforums.net\/swansont\/wp-json\/wp\/v2\/posts\/12976\/revisions"}],"wp:attachment":[{"href":"http:\/\/blogs.scienceforums.net\/swansont\/wp-json\/wp\/v2\/media?parent=12976"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/blogs.scienceforums.net\/swansont\/wp-json\/wp\/v2\/categories?post=12976"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/blogs.scienceforums.net\/swansont\/wp-json\/wp\/v2\/tags?post=12976"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}