Question

Define capillary action.

Answer 1

Capillary action, or capillarity, is the ability of a liquid to flow in narrow spaces without the assistance of, and in opposition to external forces like gravity.

Capillary action is a principle which explains why fluids are often drawn up into other substances. This phenomenon is also sometimes described as “capillarity.” A classic example of capillary action involves a paper towel and a spilled puddle of water: when the towel is dipped into the water, it sucks the water up. Capillarity explains a large number of events which occur in nature, from how trees manage to get water all the way up to their crowns to the way in which water seems to climb up a straw.