Surface energy is the energy required to increase the surface area of a liquid by a unit amount. It is a measure of the attractive forces between the molecules in the bulk of the liquid and those at the surface. The concept of surface energy is important in understanding phenomena such as wetting, adhesion, and the formation of surface films.
Surface energy is relevant in various fields such as materials science, biology, and engineering. Understanding surface energy helps in designing coatings, adhesives, and surfactants, and in studying the behavior of liquids on surfaces.