{"id":3825,"date":"2003-04-14T20:46:33","date_gmt":"2003-04-14T20:46:33","guid":{"rendered":"http:\/\/thales.mit.edu\/bush\/?p=3825"},"modified":"2021-04-15T00:46:44","modified_gmt":"2021-04-15T00:46:44","slug":"water-strider-locomotion-paradox-lost","status":"publish","type":"post","link":"https:\/\/thales.mit.edu\/bush\/index.php\/2003\/04\/14\/water-strider-locomotion-paradox-lost\/","title":{"rendered":"Water strider locomotion"},"content":{"rendered":"\n<div class=\"wp-block-media-text alignwide has-media-on-the-right is-stacked-on-mobile is-style-twentytwentyone-border has-subtle-background-color has-background tw-stack-md\"><figure class=\"wp-block-media-text__media\"><img loading=\"lazy\" decoding=\"async\" width=\"1229\" height=\"1612\" src=\"http:\/\/thales.mit.edu\/bush\/wp-content\/uploads\/2021\/02\/NATURE-Cover-WoW11.jpg\" alt=\"\" class=\"wp-image-3834 size-full\"\/><\/figure><div class=\"wp-block-media-text__content\">\n<p class=\"has-text-align-left\" style=\"font-size:16px\">Water striders Gerridae are insects of characteristic length 1 cm and weight 10 dynes that reside on the surface of ponds, rivers, and the open ocean. Their weight is supported by the surface tension force generated by curvature of the free surface, and they propel themselves by driving their central pair of hydrophobic legs in a sculling motion. Previous investigators have assumed that the hydrodynamic propulsion of the water strider relies on momentum transfer by surface waves. This assumption leads to Denny\u2019s paradox: infant water striders, whose legs are too slow to generate waves, should be incapable of propelling themselves along the surface. We here resolve this paradox through reporting the results of high-speed video and particle-tracking studies. Experiments reveal that the strider transfers momentum to the underlying fluid not primarily through capillary waves, but rather through hemispherical vortices shed by its driving legs. This insight guided us in constructing a self-contained mechanical water strider whose means of propulsion is analogous to that of its natural counterpart.<\/p>\n<\/div><\/div>\n\n\n\n<div class=\"wp-block-cover alignwide has-subtle-background-color has-background-dim\" style=\"min-height:271px;aspect-ratio:unset;\"><div class=\"wp-block-cover__inner-container is-layout-flow wp-block-cover-is-layout-flow\">\n<p class=\"tw-text-wide has-small-font-size\">See paper:&nbsp;<a href=\"http:\/\/math.mit.edu\/~bush\/wordpress\/wp-content\/uploads\/2012\/11\/nature03.pdf\">Hu, Chan and Bush, Nature (2003)<\/a>&nbsp; &nbsp; \u2026 and commentary&nbsp;<a href=\"http:\/\/math.mit.edu\/~bush\/wordpress\/wp-content\/uploads\/2012\/04\/dickinson.pdf\">Dickinson (2003)<\/a><\/p>\n\n\n\n<p class=\"tw-text-wide has-small-font-size\">SELECT PRESS: &nbsp;<a href=\"http:\/\/math.mit.edu\/~bush\/wordpress\/wp-content\/uploads\/2012\/04\/Economist.pdf\">The Economist<\/a>&nbsp;, &nbsp;<a href=\"http:\/\/www-math.mit.edu\/~dhu\/Press\/Press03\/nature\/water.htm\">Nature<\/a>&nbsp;,&nbsp;<a href=\"http:\/\/www-math.mit.edu\/~dhu\/Press\/Press03\/BBC%20NEWS%20%20Science-Nature%20%20Robot%20insect%20walks%20on%20water.htm\">BBC News<\/a>&nbsp;,&nbsp;&nbsp;<a href=\"http:\/\/math.mit.edu\/~bush\/wordpress\/wp-content\/uploads\/2012\/04\/SouthFloridaSun-Sentinel.pdf\">SouthFlorida Sun-Sentinel<\/a>&nbsp;,&nbsp;<a href=\"http:\/\/math.mit.edu\/~bush\/wordpress\/wp-content\/uploads\/2012\/04\/Article_for_Science_Dong.pdf\">Science_Dong A<\/a>&nbsp;,&nbsp;<a href=\"http:\/\/math.mit.edu\/~bush\/wordpress\/wp-content\/uploads\/2012\/04\/Ce_miracle_de_la_nature.pdf\">Ca m\u2019interesse<\/a>&nbsp;,&nbsp;&nbsp;<a href=\"http:\/\/math.mit.edu\/~bush\/wordpress\/wp-content\/uploads\/2012\/04\/Sur-LEtang-Le-Patineur-Rame.pdf\">Pour la Science<\/a>&nbsp;,&nbsp;<a href=\"http:\/\/math.mit.edu\/~bush\/wordpress\/wp-content\/uploads\/2012\/04\/Biophotonics.pdf\">Biophotonics<\/a><\/p>\n\n\n\n<p class=\"tw-text-wide has-small-font-size\">Television: &nbsp;<a href=\"http:\/\/www-math.mit.edu\/~dhu\/Press\/Press03\/Waterbug.mp4\">BBC International<\/a><\/p>\n<\/div><\/div>\n\n\n\n<p class=\"has-text-align-center tw-text-wide has-text-color\" style=\"color:#a30004\">&#8220;<strong>Like a long-legged fly upon the stream, his mind moves upon silence.<\/strong>&#8220;<br><strong>\u2013 William Butler Yeats<\/strong><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Water striders Gerridae are insects of characteristic length 1 cm and weight 10 dynes that reside on the surface of ponds, rivers, and the open ocean. Their weight is supported by the surface tension force generated by curvature of the free surface, and they propel themselves by driving their central pair of hydrophobic legs in&hellip; <a class=\"more-link\" href=\"https:\/\/thales.mit.edu\/bush\/index.php\/2003\/04\/14\/water-strider-locomotion-paradox-lost\/\">Continue reading <span class=\"screen-reader-text\">Water strider locomotion<\/span><\/a><\/p>\n","protected":false},"author":5,"featured_media":6256,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5],"tags":[],"class_list":["post-3825","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-bio","entry"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v16.3 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>Water strider locomotion - John W. M. 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