Question

Why evaporation produces cooling?

Answer 1

Answer:

Evaporation causes cooling when the "heat of evaporation" is positive. This is defined as the heat taken up by the phase transition from liquid to vapor. For water, the heat of evaporation is unusually large, so it take away so much heat so that the surface, it evaporates from gets significantly cooled.

Answer 2

Evaporation causes cooling because the process requires heat energy. The energy is taken away by the molecules when they convert from liquid into gas, and this causes cooling on the original surface.