Surface Tension of Water

Introduction:
Surface tension is the force that acts on the surface of a liquid and tends to minimize the surface area. It is caused by the cohesive forces between the liquid molecules. Water, being a liquid, also exhibits surface tension.

Effect of Temperature on Surface Tension:
The surface tension of water is influenced by various factors, including temperature. The relationship between temperature and surface tension of water can be explained as follows:

1. Increase with Decrease in Temperature: As the temperature of water decreases, the surface tension increases. This is due to the fact that at lower temperatures, the water molecules have lower kinetic energy, which results in stronger intermolecular forces. The cohesive forces between the water molecules become more significant, leading to an increase in surface tension.

2. Explanation: Surface tension is a result of the attractive forces between the water molecules. At higher temperatures, the water molecules have greater kinetic energy and move more rapidly, which weakens the intermolecular forces. As a result, the surface tension decreases.

3. Intermolecular Forces: The intermolecular forces responsible for surface tension in water are primarily hydrogen bonding. Hydrogen bonds form between the oxygen atom of one water molecule and the hydrogen atom of another water molecule. These hydrogen bonds create a network of interconnected water molecules at the surface, which gives rise to surface tension.

4. Effect on Water Droplets: Surface tension is responsible for the spherical shape of water droplets. The cohesive forces at the surface of the droplet pull the water molecules inward, creating a spherical shape that minimizes the surface area.

5. Importance in Nature and Engineering: Surface tension plays a crucial role in various natural and engineering phenomena. It allows insects like water striders to walk on water, enables capillary action in plants, and affects the behavior of liquid in small tubes and pores.

In conclusion, the surface tension of water increases with a decrease in temperature. This is due to the strengthening of intermolecular forces at lower temperatures, resulting in a higher surface tension. Understanding the relationship between temperature and surface tension is important in various fields, including civil engineering, where it can impact the behavior of fluids in structures and materials.