Surface tension

Definition

Surface tension is the energy required to increase the surface area of a liquid due to intermolecular forces. It causes the liquid to behave as if its surface were covered with a stretched elastic membrane.

5 Must Know Facts For Your Next Test

1. Surface tension arises due to cohesive forces between liquid molecules at the surface.
2. The stronger the intermolecular forces, the higher the surface tension of the liquid.
3. Surface tension allows small objects or insects to rest on a liquid's surface without sinking.
4. Temperature affects surface tension; increasing temperature generally decreases it.
5. Surface tension is measured in units of force per unit length (N/m) or energy per unit area (J/m²).

Review Questions

• What causes surface tension in liquids?
• How does temperature influence surface tension?
• Why can some insects walk on water without sinking?

Related terms

Cohesive Forces: Forces of attraction between molecules of the same substance.

Adhesive Forces: Forces of attraction between molecules of different substances.

Capillary Action: The ability of a liquid to flow in narrow spaces without external forces like gravity, due to adhesive and cohesive forces.