No One Is Quite Sure Why Ice Is Slippery

The article explores the longstanding scientific mystery of why ice is slippery, a phenomenon generally attributed to a thin, liquidlike layer on its surface. While there is consensus that this lubricating layer causes slipperiness, the exact reason for its formation remains debated. Historically, three main hypotheses have been proposed: pressure melting, frictional heating, and premelting. The pressure melting theory, originating in the mid-1800s, suggests that pressure lowers ice’s melting point, creating a water layer. However, this was challenged in the 1930s when researchers calculated that typical pressures from activities like skiing are insufficient to cause melting. The friction hypothesis posits that heat generated by friction melts the ice surface. Experiments showed that materials with different heat conduction properties affect slipperiness, supporting this idea. Yet, critics argue that frictional heating cannot explain why ice is slippery immediately upon contact, before any motion occurs. Recent microscopic experiments measuring slipperiness at varying speeds found no correlation with frictional heating, further questioning