Capillary action

Definition

Capillary action is the ability of a liquid to flow in narrow spaces without the assistance of external forces. It occurs due to the combination of cohesive forces within the liquid and adhesive forces between the liquid and surrounding surfaces.

5 Must Know Facts For Your Next Test

1. Capillary action is responsible for the upward movement of water in thin tubes, such as plant roots and stems.
2. The height to which a liquid can rise in a capillary tube is inversely proportional to the tube's radius, described by Jurin's law.
3. Cohesion refers to the attractive force between molecules of the same substance, while adhesion refers to the attractive force between different substances.
4. Surface tension plays a significant role in capillary action, as it helps maintain the shape of the liquid meniscus at the interface.
5. Common real-world examples of capillary action include ink moving through paper and water soaking into a sponge.

Review Questions

• What two types of forces are responsible for capillary action?
• How does surface tension affect capillary action?
• Explain how Jurin's law relates to capillary action.

Related terms

Cohesion: The attractive force between molecules of the same substance.

Adhesion: The attractive force between molecules of different substances.

Surface Tension: A property that allows the surface of a liquid to resist an external force, due to cohesive forces among its molecules.