Speed skater glides on ice. Ice skating works because metal skate blades glide with very little friction over a thin layer of water on the ice surface. At one time, scientists thought skaters created the water layer by melting the surface layers of ice through the pressure of their body weight. However, recent studies disproved that explanation and it is now believed ice is always slippery because the molecules in its top-most layer behave like liquid water.

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