Conversion of a substance from the liquid or solid phase into the gaseous (see gas ), or vapour, phase.
It includes boiling, in which vapour bubbles form in a liquid, and sublimation , in which a solid is converted directly to vapour. Vaporization requires that heat (the substance's latent heat of vaporization) be supplied to the liquid or solid; the same amount of heat is released by the substance in condensation , the reverse of vaporization. If the surroundings do not supply enough heat, the temperature of the remaining substance undergoing vaporization drops. See also evaporation .