Final answer:
Capillary action is a phenomenon in which liquids rise in a capillary tube. It is caused by the balance between cohesive and adhesive forces. Surface tension plays a role in capillary action and affects the shape of the liquid's meniscus.
Step-by-step explanation:
Capillary action is the phenomenon in which liquids rise into a narrow tube called a capillary. It occurs due to the balance between cohesive forces and adhesive forces. Cohesive forces are the intermolecular forces within the liquid, while adhesive forces are the attractions between the liquid and the surface of the capillary.
Surface tension, which is the energy required to increase the surface area of a liquid by a given amount, plays a role in capillary action. The curved surface in the capillary tube, known as the meniscus, is a result of surface tension. The shape of the meniscus reflects the balance between the cohesive and adhesive forces. If the adhesive forces are stronger, the liquid will be raised in the tube, and if the cohesive forces are stronger, the liquid will be suppressed.
For example, mercury has a large contact angle with glass and a large surface tension, so when placed in a tube, the surface of a column of mercury curves downward. On the other hand, water has a smaller contact angle and surface tension, resulting in an upward curved surface in a capillary tube.