Question

The weather becomes very pleasant in cold countries when rivers and lakes start melting. Explain as clearly as possible.

Answer 1

1. In cold countries, when the water in the rivers and lakes starts freezing, it releases the latent heat of fusion into the surrounding air.
2. The amount of heat energy required to convert one kilogram of ice into the water at 0 °C, is called the specific latent heat of fusion of ice.
3. Every kilogram of water liberates 336000 J of heat energy on freezing.
4. Hence, on absorbing the heat from the water bodies, the surrounding air becomes warmer and the weather becomes pleasant.
5. This is the reason why weather becomes pleasant when the rivers and lakes start freezing in cold countries.