Capillary action, also referred to as capillary motion or capillarity, is a combination of cohesion\/ adhesion and surface tension forces. Capillary action is demonstrated by the upward movement of water through a narrow tube against the force of gravity. Capillary action occurs when the adhesive intermolecular forces between a liquid, such as water, and the solid surface of the tube are stronger than the cohesive intermolecular forces between water molecules.