{"id":1194,"date":"2012-05-09T09:39:38","date_gmt":"2012-05-09T09:39:38","guid":{"rendered":"http:\/\/junq.info\/?p=1194"},"modified":"2012-05-09T10:49:53","modified_gmt":"2012-05-09T10:49:53","slug":"question-of-the-month-why-does-coffee-form-ring-shaped-stains","status":"publish","type":"post","link":"http:\/\/junq.info\/?p=1194","title":{"rendered":"Question of the Month: Why does coffee form ring-shaped stains?"},"content":{"rendered":"<p><strong>Every morning it&#8217;s the same: A few drops of coffee end up on your table. And once they dry, they form ring-shaped stains. But why? This problem is related to the question how to build tomorrow&#8217;s communication systems.<\/strong><\/p>\n<p>Some of you might remember your grandma&#8217;s coffee pot, which had a sponge attached to the spout. This was done to avoid coffee stains. These stains &#8211; black on the outside, white on the inside and always round in shape &#8211; are also interesting for science, especially for nanotechnology.<\/p>\n<p>Physicists might use the coffee stains as a model to design better communication systems in the future. This is why the question of the month reads:<\/p>\n<p>&#8220;Why does coffee always form ring-shaped stains and not a chaotic splash?&#8221;<\/p>\n<p>Detektor.fm asked Leonie Anna Mueck, Editor of the Journal of Unsolved Questions.<\/p>\n<p><a href=\"http:\/\/detektor.fm\/wirtschaft\/die-ungeloeste-frage-des-monats-warum-macht-kaffee-ringfoermige-flecken\/\">Listen to the podcast here.<\/a><\/p>\n<p>Read more about self-assembly in colloidal dispersions here:<a href=\"http:\/\/prl.aps.org\/abstract\/PRL\/v107\/i8\/e085502\"> A. Marin et al. &#8220;Order-to-disorder transition in ring-shaped colloidal stains&#8221;, Phys. Rev. Lett.                       107,                       085502                       (2011)<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Every morning it&#8217;s the same: A few drops of coffee end up on your table. And once they dry, they form ring-shaped stains. But why? This problem is related to the question how to build tomorrow&#8217;s communication systems. Some of you might remember your grandma&#8217;s coffee pot, which had a sponge attached to the spout.&hellip;&nbsp;<a href=\"http:\/\/junq.info\/?p=1194\" class=\"\" rel=\"bookmark\">Read More &raquo;<span class=\"screen-reader-text\">Question of the Month: Why does coffee form ring-shaped stains?<\/span><\/a><\/p>\n","protected":false},"author":8,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":true,"template":"","format":"standard","meta":{"neve_meta_sidebar":"","neve_meta_container":"","neve_meta_enable_content_width":"","neve_meta_content_width":0,"neve_meta_title_alignment":"","neve_meta_author_avatar":"","neve_post_elements_order":"","neve_meta_disable_header":"","neve_meta_disable_footer":"","neve_meta_disable_title":"","footnotes":""},"categories":[1],"tags":[],"aioseo_notices":[],"_links":{"self":[{"href":"http:\/\/junq.info\/index.php?rest_route=\/wp\/v2\/posts\/1194"}],"collection":[{"href":"http:\/\/junq.info\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/junq.info\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/junq.info\/index.php?rest_route=\/wp\/v2\/users\/8"}],"replies":[{"embeddable":true,"href":"http:\/\/junq.info\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1194"}],"version-history":[{"count":4,"href":"http:\/\/junq.info\/index.php?rest_route=\/wp\/v2\/posts\/1194\/revisions"}],"predecessor-version":[{"id":1201,"href":"http:\/\/junq.info\/index.php?rest_route=\/wp\/v2\/posts\/1194\/revisions\/1201"}],"wp:attachment":[{"href":"http:\/\/junq.info\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1194"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/junq.info\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1194"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/junq.info\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1194"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}