Evaporation

What is Evaporation?

Evaporation is a form of vaporisation that usually happens on the surface of liquids and it involves the transition of the liquid particles into the gaseous phase.

Applications of Evaporative Cooling

1. We sweat in order to cool our bodies.
2. During the summer, we wear cotton clothes.
3. Water is stored in earthen pots to make it cool.

How does evaporation causes cooling?

When a molecule at the surface uses enough energy to exceed the vapour pressure, the liquid particles will typically escape and enter the surrounding air as a gas. The energy taken from the vaporised liquid during evaporation lowers the temperature of the liquid, resulting in evaporative cooling.

Why should we wear cotton clothes in summer?

We wear cotton clothes during summer as cotton absorbs sweat from the body, exposing to the atmosphere for easy evaporation. As we tend to sweat more during summer and cotton fabric absorbs sweat and help body to cool down.

Why do we see water droplets on the outersurface of a glass containing ice-cold water?

The water vapour present in the air comes in contact with cold surface of the glass, loses its energy and gets converted into droplets of water.