Surface Tension

Surface tension is a property of the surface of a liquid that allows it to resist an external force. It is a result of the cohesive forces between the molecules of the liquid. This cohesive force creates a "skin" on the surface of the liquid, causing it to behave as if it were a thin, elastic sheet.

Factors Affecting Surface Tension

The surface tension of a liquid is influenced by several factors:

1. Molecular Attraction: The strength of the cohesive forces between the molecules of the liquid affects the surface tension. For example, water, with its strong hydrogen bonding, has higher surface tension compared to liquids with weaker intermolecular forces.
2. Temperature: Generally, surface tension decreases with an increase in temperature due to the increased kinetic energy of the molecules, which weakens the cohesive forces.
3. Impurities: The presence of impurities can reduce surface tension by disrupting the cohesive forces between the molecules at the surface of the liquid.
4. Surfactants: Compounds such as soaps and detergents can decrease surface tension by interfering with the cohesive forces between the liquid molecules.

Applications of Surface Tension

Surface tension has several important applications in biology and everyday life:

• Capillary Action: Surface tension allows liquids to move against gravity in narrow spaces, such as the movement of water in plant roots and the use of capillary tubes in laboratory experiments.
• Formation of Droplets: Surface tension causes liquids to form spherical droplets, which is important in processes like raindrop formation and the use of ink in pens.
• Water Striders: Certain insects, like water striders, can walk on water due to the high surface tension of water, which allows them to distribute their weight effectively.

Study Guide

When studying surface tension, focus on the following key points:

1. Understand the concept of surface tension and its causes.
2. Learn how to calculate surface tension and understand its units of measurement.
3. Explore the factors that affect surface tension and their implications.
4. Examine the biological and practical applications of surface tension.
5. Practice solving problems related to surface tension to reinforce your understanding.

Remember to review diagrams and real-life examples to visualize the effects of surface tension in different scenarios.