What does evaporation refer to in terms of phase change?

Evaporation refers to the process in which a substance transitions from the liquid phase to the gas phase. This phase change occurs when molecules in a liquid gain enough energy, typically from heat, to overcome intermolecular forces that hold them closely together in a liquid state. As a result, these energized molecules escape into the atmosphere as gas.

This process is commonly observed when water is heated, such as in a pot on a stove, where the heat causes the liquid water to evaporate into steam. Evaporation can occur at any temperature, not just at boiling point, and is influenced by factors such as temperature, surface area, and air movement.

Each of the other options describes a different phase change. The transition from solid to liquid is known as melting, gas to liquid describes condensation, and liquid to solid is referred to as freezing. Understanding these distinctions helps to clarify the specific nature of each phase change in relation to temperature and energy changes in matter.