For a long time, people believed that the pressure from a skate blade melted the surface of the ice to create a thin, slippery layer of water. Scientists and engineers in the late 1800s demonstrated that the pressure of an ice skate blade could lower the melting point of ice from 0°C to −3.5°C. For decades, pressure melting was accepted as the standard explanation for how ice skates work. For some reason, no one pointed out that it was possible to skate at temperatures colder than −3.5°C. The pressure melting theory suggests it should be impossible, but ice skaters do it all the time.
