* Salt dissolves in water, pepper does not. Salt is readily soluble in water, meaning it dissolves and creates a saltwater solution. This solution has a lower freezing point than pure water. When salt is sprinkled on ice, it dissolves a bit, creating a layer of saltwater. This saltwater solution has a lower freezing point than the ice, so it melts the ice around it.

* Pepper does not dissolve in water. Pepper is hydrophobic, meaning it repels water. It does not dissolve in water and will not create a solution that can lower the freezing point.

* Salt lowers the freezing point of water. This phenomenon is called freezing point depression. The presence of dissolved substances, like salt, disrupts the regular arrangement of water molecules and makes it harder for them to freeze.

Here's a simple explanation:

Imagine the ice is a frozen lake. Salt can walk onto the lake and break up the ice by creating a layer of saltwater around it. Pepper, on the other hand, can't walk on the lake because it doesn't dissolve. It just sits on top, not affecting the ice below.

In summary: Salt melts ice faster than pepper because it dissolves in water and lowers the freezing point, while pepper does not dissolve and has no effect on the freezing point of water.