Capillary Action

Capillary action, also known as capillarity, is the ability of a liquid to flow through narrow spaces, such as small tubes or porous materials, due to intermolecular forces between the liquid and the surrounding surfaces. Capillary action occurs because the adhesive forces between the liquid molecules and the solid surfaces are stronger than the cohesive forces between the liquid molecules themselves. This results in the liquid being drawn into narrow spaces, often against the force of gravity, and may also cause the liquid to spread out or wet the surface. Capillary action is important in many natural and technological processes, such as plant transport of water and nutrients, ink and dye penetration into paper or fabric, and the flow of liquids through small tubes or filters.