{"id":7231,"date":"2013-03-03T23:55:56","date_gmt":"2013-03-04T07:55:56","guid":{"rendered":"http:\/\/blog.kootenay-lake.ca\/?p=7231"},"modified":"2013-03-07T12:07:20","modified_gmt":"2013-03-07T20:07:20","slug":"hoodie-ripples","status":"publish","type":"post","link":"https:\/\/blog.kootenay-lake.ca\/?p=7231","title":{"rendered":"Hoodie ripples"},"content":{"rendered":"<p>&nbsp;<\/p>\n<p>A Hooded Merganser plied zebrine waters.<\/p>\n<p>The astute observer might guess that this posting was made solely so I could use the word <em>zebrine<\/em>. After all, I am guilty of taking as much pleasure from interesting words as from interesting images. Indeed, as I <a href=\"https:\/\/blog.kootenay-lake.ca\/?p=6654\">responded<\/a> to one correspondent who commented upon my choice of language: &#8220;fun with pictures; fun with words.&#8221;<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignright size-full wp-image-7232\" onclick=\"return false\" onmousedown=\"return false\" alt=\"\" src=\"https:\/\/blog.kootenay-lake.ca\/wp-content\/uploads\/2013\/03\/hoodedmerganser130303as.jpg\" width=\"720\" height=\"480\" \/><\/p>\n<p>The picture holds more delights for me than just the patterns of reflection.\u00a0Those zebra-like waves depend upon gravity as a restoring force, while the hoodie&#8217;s bow ripples depend upon surface tension. One can tell the difference between waves and ripples merely by watching the behaviour of each.<\/p>\n<p>The dividing line between waves and ripples is a length of 1.7 cm. When the crest-to-crest distance, or wavelength, is greater than 1.7 cm, the primary restoring force of disturbed water is gravity (rather like a pendulum) and the undulations are called waves. When the crest-to-crest distance, or wavelength, is less than 1.7 cm, the primary restoring force of disturbed water is surface tension (rather like a trampoline) and the undulations are called ripples (also called capillary\u00a0waves).<\/p>\n<p>There is an interesting difference in the behaviour of waves and ripples. With a wave, the greater the wavelength the faster it moves. So, a wave with a one-meter wavelength travels faster than one with a ten-centimetre wavelength. However with a ripple it is the other way around: the shorter the wavelength the faster it moves. So a ripple with a one-millimetre\u00a0wavelength travels faster than one with a one-centimeter wavelength.<\/p>\n<p>There is a detail of the picture below. The duck disturbs the water ahead of it, but the disturbances that have travelled farthest ahead have a narrower spacing than those nearby. These are ripples where the shortest wavelengths have travelled out from the duck both fastest and farthest. Although gravity is the restoring force for those broader (zebrine) waves, surface tension is the restoring force for the tiny ones ahead of the hoodie.<br \/>\n<img loading=\"lazy\" decoding=\"async\" class=\"alignright size-full wp-image-7233\" onclick=\"return false\" onmousedown=\"return false\" alt=\"\" src=\"https:\/\/blog.kootenay-lake.ca\/wp-content\/uploads\/2013\/03\/hoodedmerganser130303as2.jpg\" width=\"720\" height=\"480\" \/><\/p>\n<p>Offering even more water fun, the Hooded Merganser then splashed.<br \/>\n<img loading=\"lazy\" decoding=\"async\" class=\"alignright size-full wp-image-7234\" onclick=\"return false\" onmousedown=\"return false\" alt=\"\" src=\"https:\/\/blog.kootenay-lake.ca\/wp-content\/uploads\/2013\/03\/hoodedmerganser130303bs.jpg\" width=\"720\" height=\"480\" \/><\/p>\n<p>And soon climbed onto some shore ice and presented a rather impudent stance.<br \/>\n<img loading=\"lazy\" decoding=\"async\" class=\"alignright size-full wp-image-7238\" onclick=\"return false\" onmousedown=\"return false\" alt=\"hoodedmerganser130303cs\" src=\"https:\/\/blog.kootenay-lake.ca\/wp-content\/uploads\/2013\/03\/hoodedmerganser130303cs.jpg\" width=\"720\" height=\"480\" \/><\/p>\n","protected":false},"excerpt":{"rendered":"<p>&nbsp; A Hooded Merganser plied zebrine waters. The astute observer might guess that this posting was made solely so I could use the word zebrine. After all, I am guilty of taking as much pleasure from interesting words as from &hellip; <a href=\"https:\/\/blog.kootenay-lake.ca\/?p=7231\">Continue reading <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[9,12],"tags":[],"class_list":["post-7231","post","type-post","status-publish","format-standard","hentry","category-birds","category-weather"],"_links":{"self":[{"href":"https:\/\/blog.kootenay-lake.ca\/index.php?rest_route=\/wp\/v2\/posts\/7231","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blog.kootenay-lake.ca\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.kootenay-lake.ca\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.kootenay-lake.ca\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.kootenay-lake.ca\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=7231"}],"version-history":[{"count":20,"href":"https:\/\/blog.kootenay-lake.ca\/index.php?rest_route=\/wp\/v2\/posts\/7231\/revisions"}],"predecessor-version":[{"id":26747,"href":"https:\/\/blog.kootenay-lake.ca\/index.php?rest_route=\/wp\/v2\/posts\/7231\/revisions\/26747"}],"wp:attachment":[{"href":"https:\/\/blog.kootenay-lake.ca\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=7231"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.kootenay-lake.ca\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=7231"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.kootenay-lake.ca\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=7231"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}