The temperature remains constant during the change of state for any substance because the heat energy supplied is used not to increase the kinetic energy (and thus temperature) of the particles, but to overcome the intermolecular forces holding the particles together in one state. This energy is called latent heat. During this phase transition, all the supplied heat goes into breaking or forming these bonds rather than raising the temperature. Hence, the temperature stays constant until the entire substance has completed the change of state, such as melting, boiling, freezing, or condensation.