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During the UK\u2019s recent snowy and icy spell, you might have tried salting your driveway to prevent, or \u201cmelt\u201d, ice.<\/a><\/p>\n<\/div>\n That likely works because of an ongoing battle between water and ice on the top layer of a slippery sheet. Sodium\u2019s structure means its ions break apart in water<\/a>, making it harder for H2O molecules to stick together \u2013 thus lowering the melting point of ice.<\/p>\n<\/div>\n Until recently, most scientists thought that a thin layer of water on ice was to blame for its slipperiness, too. The idea was <\/a>that pressure or friction applied to ice led its top layer to melt, leaving a slick film of liquid.<\/p>\n<\/div>\n But recent research, published in Physical Review Letters<\/a>, has blown that theory apart. <\/p>\n<\/div>\n The water theory might not explain why ice stays slippery in temperatures well below freezing, The Conversation<\/a> previously noted.<\/p>\n<\/div>\n Scientists at Saarland University in Germany wanted to explore why that might be. So, they ran molecular simulations of ice interfaces through advanced computer systems to see if they could work out what was really going on. <\/p>\n<\/div>\n In a press statement<\/a>, study author Professor Martin M\u00fcser said: \u201cIt turns out that neither pressure nor friction plays a particularly significant part in forming the thin liquid layer on ice\u201d. <\/p>\n<\/div>\n Their research suggested that instead, something happens to the strict molecular structure needed to keep ice solid when we step on it, thanks to molecular dipoles. <\/p>\n<\/div>\n Molecular dipoles happen, Saarland University explained<\/a>, when \u201ca molecule has regions of partial positive and partial negative charge, giving the molecule an overall polarity that points in a specific direction\u201d. <\/p>\n<\/div>\n Ice relies on a very neat and exact crystalline formation of molecules in order to stay solid. <\/p>\n<\/div>\n But when we, for instance, step on ice, the direction of the dipoles in our shoe sole interacts with those in the ice, this study suggested. <\/p>\n<\/div>\n That means the previously-perfect structure of ice crystals falls apart. <\/p>\n<\/div>\n \u201cIn three dimensions, these dipole-dipole interactions become \u2018frustrated,\u2019\u201d Professor M\u00fcser explained.<\/p>\n<\/div>\n This, Saarland University said, refers to \u201ca concept in physics where competing forces prevent a system from achieving a fully ordered stable configuration\u201d.<\/p>\n<\/div>\n Well, for one thing, it could mean that skiing at very cold temperatures is more possible than we previously thought. <\/p>\n<\/div>\n \u201cUntil now, it was assumed that skiing below -40\u00b0C is impossible because it\u2019s simply too cold for a thin lubricating liquid film to form beneath the skis. That too, it turns out, is incorrect,\u2019 said Professor M\u00fcser<\/a>.<\/p>\n<\/div>\n \u201cDipole interactions persist at extremely low temperatures. Remarkably, a liquid film still forms at the interface between ice and ski \u2013 even near absolute zero,\u201d he added, though at this temperature the liquid may be too viscous to actually facilitate much movement. <\/p>\n<\/div>\n Saarland University noted that the implications of this discovery are yet to be fully seen, though the \u201cscientific community is taking notice\u201d. <\/p>\n<\/div>\n<\/div>\nWhy is ice really slippery? <\/strong><\/h2>\n<\/p>\n
What are molecular dipoles, and why might they make ice slippery?<\/strong><\/h3>\n<\/p>\n
What does this mean? <\/strong><\/h3>\n<\/p>\n