{"id":15038,"date":"2014-06-23T03:00:19","date_gmt":"2014-06-23T08:00:19","guid":{"rendered":"http:\/\/blogs.scienceforums.net\/swansont\/?p=15038"},"modified":"2016-02-22T21:14:03","modified_gmt":"2016-02-22T21:14:03","slug":"its-not-all-black-and-white","status":"publish","type":"post","link":"http:\/\/blogs.scienceforums.net\/swansont\/archives\/15038","title":{"rendered":"It’s Not All Black and White"},"content":{"rendered":"

Incredible art piece dances with polarized light<\/a><\/p>\n

There’s a video in the link with the art, which is a weird combination of kinetic sculpture and optical effects from polarizers. You don’t discern the actual motion of the polarizers, but you see a motional effect from the overlap. Sort of an opto-kinetic sculpture.<\/p>\n

One thing:<\/p>\n

Polarizers are pieces of plastic made to only allow (or disallow) the transmission of light with certain polarizations. Natural light has a mixture of all different polarizations of light, and so any one of these polarizers only filters out a portion of the light. However, if you stack two with complementary polarizations, such as one that blocks about 50% of light and another that blocks the other 50% of light, then you end up with a totally opaque whole.<\/p><\/blockquote>\n

To quote a phrase: that’s not how this works! That’s not how any of this works! Simple filters don’t add linearly (they multiply \u2014 two simple 50% filters would block 75% of the light), and polarizers don’t block half each. What’s actually going on is that one polarizer sets the polarization of the light (filtering the fraction that is cross-polarized), and then the second one blocks more light, both acting according to the Law of Malus<\/p>\n

\\(I=I_0 \\cos^2 \\theta\\)<\/p>\n

All the light is blocked for perpendicular orientations of the polarizers, and at varying levels of light at other angles. Randomly polarized light isn’t blocked by 50% \u2014 the transmitted intensity is roughly 75%. You can see single polarizers in the video, and tell they aren’t blocked by half.<\/p>\n

The second piece is in color but only has a still shot, so I don’t know if this is color filters or polarization with birefringent materials. I’ve posted static shots<\/a> of birefringent<\/a> materials before, both using a static linearly polarized source (LCD); having the background and\/or foreground polarization and birefringent material move might make for an interesting display.<\/p>\n","protected":false},"excerpt":{"rendered":"

Incredible art piece dances with polarized light There’s a video in the link with the art, which is a weird combination of kinetic sculpture and optical effects from polarizers. You don’t discern the actual motion of the polarizers, but you … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4,39],"tags":[],"class_list":["post-15038","post","type-post","status-publish","format-standard","hentry","category-art","category-physics"],"_links":{"self":[{"href":"http:\/\/blogs.scienceforums.net\/swansont\/wp-json\/wp\/v2\/posts\/15038","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=15038"}],"version-history":[{"count":1,"href":"http:\/\/blogs.scienceforums.net\/swansont\/wp-json\/wp\/v2\/posts\/15038\/revisions"}],"predecessor-version":[{"id":15791,"href":"http:\/\/blogs.scienceforums.net\/swansont\/wp-json\/wp\/v2\/posts\/15038\/revisions\/15791"}],"wp:attachment":[{"href":"http:\/\/blogs.scienceforums.net\/swansont\/wp-json\/wp\/v2\/media?parent=15038"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/blogs.scienceforums.net\/swansont\/wp-json\/wp\/v2\/categories?post=15038"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/blogs.scienceforums.net\/swansont\/wp-json\/wp\/v2\/tags?post=15038"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}