what is capillary action?

Answer 1

Capillary action, capillarity, or capillary motion is the ability of a substance (the standard reference is to a tube in plants but can be seen readily with porous paper) to draw another substance into it. It occurs when the adhesive intermolecular forces between the liquid and a substance are stronger than the cohesive intermolecular forces inside the liquid. The effect causes a concave meniscus to form where the substance is touching a vertical surface. The same effect is what causes porous materials to soak up liquids.

A common apparatus used to demonstrate capillary action is the capillary tube. When the lower end of a vertical glass tube is placed in a liquid such as water, a concave meniscus forms. Surface tension pulls the liquid column up until there is a sufficient weight of liquid for gravitational forces to overcome the intermolecular forces. The weight of the liquid column is proportional to the square of the tube's diameter, but the contact area between the liquid and the tube is proportional only to the diameter of the tube, so a narrow tube will draw a liquid column higher than a wide tube. For example, a glass capillary tube 0.5 mm in diameter will lift a theoretical 2.8 cm column of water. Actual observations show shorter total distances.

With some pairs of materials, such as mercury and glass, the interatomic forces within the liquid exceed those between the solid and the liquid, so a convex meniscus forms and capillary action works in reverse.

Answer 2

This is a proposed solution to the method which trees and plants bring water to nourish the upper sections of itself. Capillary acton occurs in very thin tubes where water cohesion and water pressure causes water to rise slowly.

This can be demonstrated yourself with thin glass tubes - they must be significantly thinner than straws. Most scientist agree nowdays that capillary action at most contributes some to the movement of water upwards. Transpiration pull is generally considered the more forceful of the methods.

Answer 3

Capillary action is the ability of water to rise up through thin tubes due to the polar nature of water molecules.

Answer 4

Due to the cohesive bond (surface tension) of water molecules, it can travel up thin vessels like the inside of a plant, or the microscopic "tubes" that make up a sponge or other absorbent material. This is capillary action

Answer 5

They are actions that capillaries take when they need to be active.