1. Melting

Change of state from solid to liquid, without a change in temperature.

During melting, temperature remains constant at the melting point. Thermal energy is absorbed by the substance.

2. Solidification

Change of state from liquid to solid, witjout a change in temoerature.

During solidification, the temperature remails constant at the freezing point. Thermal energy is released by the substance.

3. Boiling

Change of state from liquid into vapour (gas), happening at a constant temperature; boiling point.

During boiling, the temperature remains constant at its boiling point. Thermal energy is absorbed by the substance.

4. Condensation

The process where vapour (gas) changes into liquid at a constant temperature. Heat is given out during the process.

During condensation, the temperature remains constant at the condenstion point. Thermal energy is released by the substance.

5. Evapouration

A cooling process

Evapouration of a liquid is due to molecules at the surface with energy greater then the average kinetic energy escaping from the rest of the liquid.