Boiling

Boiling is the process by which a liquid turns into a vapor when it is heated to its boiling point. The change from a liquid phase to a gaseous phase occurs when the vapor pressure of the liquid is equal to the atmospheric pressure exerted on the liquid.

Video: Boiling

Boiling is a physical change and molecules are not chemically altered during the process. When atoms or molecules of a liquid are able to spread out enough to change from a liquid phase to a gaseous phase, bubbles form and boiling occurs.