{"id":444,"date":"2018-05-30T15:43:20","date_gmt":"2018-05-30T15:43:20","guid":{"rendered":"http:\/\/163.180.4.222\/lab\/?p=444"},"modified":"2019-10-15T18:13:13","modified_gmt":"2019-10-15T09:13:13","slug":"why-your-feet-slip-and-slide-on-ice","status":"publish","type":"post","link":"https:\/\/biochemistry.khu.ac.kr\/lab\/?p=444","title":{"rendered":"Why your feet slip and slide on ice"},"content":{"rendered":"

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Ice is slippery because molecules in the surface layer are only loosely bound to each other. Credit: Getty<\/p>\n<\/figcaption><\/figure>\n

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Why your feet slip and slide on ice<\/h1>\n
Experiments and simulations disprove an old theory.<\/div>\n<\/header>\n<\/div>\n<\/div>\n
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Skaters slide across ice because they\u2019re riding atop a layer of rolling molecules \u2014 not because\u00a0the skates melt the ice as they go, as was previously thought.<\/p>\n

Daniel Bonn at the University of Amsterdam and his collaborators measured the friction of a\u00a0metal ball sliding on ice at temperatures from \u2212100\u2009\u00b0C to 0\u2009\u00b0C. At the colder end of that range,\u00a0friction was high. But at around \u221270\u2009\u00b0C, friction began to decrease, reaching a minimum at\u00a0\u22127\u2009\u00b0C \u2014 the ice temperature at typical speed-skating rinks.<\/p>\n

Molecular dynamic simulations suggested that each molecule in a microscopic layer on the ice\u00a0surface forms a bond with two to three others, compared with four bonds in the bulk of the ice.<\/p>\n

As temperature warms above \u221270\u2009\u00b0C, the proportion of molecules with just two bonds begins\u00a0to increase. These act like a layer of rolling logs, allowing a skater \u2014 or an unlucky pedestrian\u00a0\u2014 to glide along their surface.<\/p>\n

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J. Phys. Chem. Lett.<\/i>\u00a0(2018)<\/a><\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/article>\n<\/div>\n

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      (\uc6d0\ubb38)     Ice is slippery because molecules in the surface layer are only loosely bound to each other. 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