Which statement best explains why ice is slippery?

Which statement best explains why ice is slippery?

• A. It has a smooth surface
• B. It has no friction
• C. It is very chilly
• D. Pressure increase causes melting at contact

Answer: (D)

The slippery feel comes from a thin film of liquid water that forms at the contact surface when pressure is applied. When you press ice against another surface, the pressure at the interface increases enough to locally lower the melting point of ice, causing a small amount of melting right there. This liquid layer acts as a lubricant, so the objects can slide over each other with much less resistance than on a dry ice surface. As you move, the layer is continuously formed and squeezed, keeping friction low. That’s why the idea that pressure increase causes melting at the contact is the best explanation. A smooth surface by itself isn’t the main reason for slipperiness, friction isn’t zero, and being very chilly isn’t the mechanism—the key factor is the pressure-driven formation of a lubricating water film.

The slippery feel comes from a thin film of liquid water that forms at the contact surface when pressure is applied. When you press ice against another surface, the pressure at the interface increases enough to locally lower the melting point of ice, causing a small amount of melting right there. This liquid layer acts as a lubricant, so the objects can slide over each other with much less resistance than on a dry ice surface. As you move, the layer is continuously formed and squeezed, keeping friction low.

That’s why the idea that pressure increase causes melting at the contact is the best explanation. A smooth surface by itself isn’t the main reason for slipperiness, friction isn’t zero, and being very chilly isn’t the mechanism—the key factor is the pressure-driven formation of a lubricating water film.