Question
How are clouds formed ? Classify them.
Solution
Cloud is a mass of minute droplets of water or tiny crystals of ice formed by the condensation of the water vapour in free air at a considerable elevation. As the clouds are formed at some height over the surface of the earth, they take various shapes. The clouds are classified as under according to their height, expanses, density and transparency.
1. Cirrus: These are formed at high altitudes (8,000–12,000m).
2. Cumulus: They are formed at a height of 4,000–7,000m. They look like cotton.
3. Stratus: They are layered clouds covering large portions of the sky.
4. Nimbus: These are black or dark grey rain clouds. They are very near to the earth’s surface.
