Heat of Vaporization

Heat of Vaporization: Energy Released During the Evaporation of Water

When a liquid evaporates into the gaseous phase of another substance, it is called evaporation, e.g., when water evaporates in the gas mixture of air. The heat of vaporization generated in this process is drawn from the liquid, resulting in so-called evaporative cooling.

This process occurs daily during sweating: for example, when the outside temperature is too high, the body secretes sweat. This sweat evaporates upon contact with the air, whereby the heat of vaporization is released into the air. The sweat becomes "colder," thus cooling the skin.