Latent Heat

Latent heat is the quantity of heat absorbed or released by a substance undergoing a change of state (for example, ice changing to water or water to steam), at constant temperature and pressure. When a solid material is heated and reaches its melting point, it goes from solid to liquid. During this process the material absorbs a certain amount of heat. Despite the heat input, the temperature of the material stays at a relatively constant level, even though phase change is taking place.