What process occurs when water turns to ice?

The process that occurs when water turns to ice is known as the heat of fusion. Heat of fusion refers to the amount of energy required to change a substance from a liquid to a solid at its melting/freezing point. When water freezes, it releases energy in the form of heat, which is why the process is characterized by this term.

In the context of water, as the temperature drops and reaches the freezing point (0°C or 32°F), water molecules lose kinetic energy and begin to form solid ice through the process of crystallization. This exchange of heat is crucial because it involves the transformation of the state of matter from liquid to solid while maintaining the same temperature until the phase change is complete.

While evaporation refers to the transition from liquid to gas and condensation describes the reverse process, they are not relevant to the freezing of water. Heat of vaporization, on the other hand, pertains to the energy required to convert a liquid into a gas and does not apply to the freezing process.