Theory/Capillarity

Capillary Action

Capillary action, or capillarity, is the ability of a liquid to flow against gravity such as in the narrow space of a thin tube or in porous materials such as paper or in some non-porous materials such as liquified carbon fibre. Capillarity causes liquids to flow against the force of gravity or the force of magnetic field induction because the inter-molecular attractive forces between the liquid and solid surrounding surfaces or the liquid to itself are stronger than the opposing force(s). If the diameter of a tube is sufficiently small, then the combination of surface tension (which is caused by cohesion within the liquid) and forces of adhesion between the liquid and container act to lift the liquid.