In this educational resource you can check the next physical phenomenon: when there is a change of state in pure substances, the temperature remains constant.

The educational resource shows an interactive animation about the equilibrium between different states: a substance (water, for example) in different states at different temperatures (ice and water) will eventually reach an equilibrium temperature.

The educational resource shows an interactive animation about changes in water: the change from a solid to a liquid is called fusion. The change from a liquid to a gas is called evaporation. When water boils it is called ebullition.

Concept of equilibrium in liquids

The educational resource shows an interactive animation about the change of phase: solids melt when they are heated and liquids evaporate, changing to a gaseous state. If you increase the vibration of the molecules you can see how water changes phase.