Evaporation occurs as a result of the energy transfer between molecules due to random collisions that can excite molecules to turn from liquid to gas. While some level of evaporation can occur at a temperature below the liquid's boiling point, adding energy, typically through heat, is necessary to induce evaporation.
Evaporation can be seen both in natural and artificial processes. Evaporation is a major step of the water cycle. Liquid water in the ground and pools of water evaporate, often with the help of the sunlight's heat, and rise until they condense into clouds. Evaporation is also a critical part of many chemical processes, like distillation, where substances are separated from mixtures by evaporating and condensing the one with a lower boiling point.