How can an ice skate glide forward but grip during a turn?

An ice skater can slide smoothly across a rink and then carve a turn. The same blade seems slippery in one moment and grippy in the next. Its broad sliding surface and sharp edges interact with ice in different ways.

Ice friction depends on temperature, speed, pressure, and the contact surfaces. Near the surface, water molecules can be more mobile than molecules deeper in the solid. Sliding and deformation can also change the contact region. The explanation is more complicated than saying that a skater’s weight simply melts all the ice beneath a blade.

When a smooth part of the blade glides along the surface, resistance can be low. Tilting the skate places more of the load on a narrow edge. The concentrated contact can cut or plow into the ice. Ice then pushes against the blade sideways, allowing the skater to change direction.

To gain speed, the skater pushes against the ice with an angled blade. The ice’s response includes a forward component. A blade that had no sideways grip would make controlled starts and turns much harder. Successful skating depends on having low resistance in the glide direction and enough grip where a push is needed.