Surface Tension

Detergents reduce the surface tension of water, allowing it to spread and wet clothes more effectively. They also form micelles that trap grease and dirt, allowing them to be rinsed away.

Surface energy is the energy needed to increase the surface area of a liquid by one unit area. It is associated with the force acting at the liquid's surface that resists expansion. Surface tension, which is the force per unit length acting along the surface, is directly related to surface energy. The relationship between surface energy and surface tension is expressed as: where is the length of the line along the surface.