For those who live in colder climates, slippery ice defines winter: in skating rinks, on frozen ponds, and on dangerously slick roads and sidewalks.
But why is ice so slippery?
It turns out that scientists didn’t really know the answer to that simple question until recently. But new research has shown that ice’s slipperiness may be due to “extra” molecules on the surface of the ice. [The Mysterious Physics of 7 Everyday Things]
Old theories make no sense Because ice is less dense than liquid water, its melting point is lowered under high pressures. A long-standing theory says that this is what causes ice to be slippery: As you step on it, [...]