Freezing is the change of a liquid into a solid. This occurs when a liquid loses heat to its surroundings.
The liquid molecules lose kinetic energy as they lose heat, causing them to move around less vigorously.
At the melting point temperature, the molecules begin to lose potential energy. They become unable to overcome the intermolecular attractive forces.
The intermolecular forces cause molecules to become fixed in place. Movement becomes limited to vibrations and rotations, causing the substance to freeze.
The temperature remains constant during the freezing period. The heat removed is latent heat.