Ice is slippery. This is a fundamental fact we humans have dealt with so often that we rarely take the time to ask why. Other solids aren’t inherently slippery, so what is it that makes ice so? Remarkably, scientists only began to ask this question and propose theories within the past couple hundred years. One common suggestion is that the high pressure of an ice skate on ice locally melts the ice, creating a thin liquid layer a skater glides across. But this does not explain why ice is slippery for shoes or tires, nor why it’s possible to ice skate at more than a few degrees below freezing. Several other effects may be in play, such as frictional heating or the peculiar molecular forces between water molecules. Current research suggests that ice has a thin liquid layer tens or hundreds of nanometers thick that causes its slippery nature. For a great review of the subject, see Robert Rosenberg’s Physics Today article. (Video credit: SciShow)
Why Ice is Slippery
