Here's why:

* Kinetic Energy: Molecules in a liquid are constantly moving. Some have more kinetic energy than others.

* Surface Escape: Those with enough kinetic energy can overcome the attractive forces holding them within the liquid and escape into the surrounding air.

* Vaporization: This process of changing from a liquid to a gas is called vaporization. Evaporation is a specific type of vaporization that occurs at the surface of a liquid.

Let me know if you have any other questions!