A blizzard is a blinding storm of snow and wind which is common in the Polar Regions. A violent cyclonic storm is called tornado.
Rain is caused when the heat of the sun changes much of the water of the sea, rivers and lakes into water vapor. When this moisture-laden air ascends into the colder, higher regions of the atmosphere or is blown there by winds, it becomes cooled. The drops of water then unite and fall on the earth as rain.
Dew is formed during the night. The earth cools more quickly in the night than the air above it. The layer of air nearest to the earth becomes cooled. The moisture deposited on the ground, grass and other objects, is called dew.
The rainbow is formed when the sun’s rays pass through the drops of rainwater in the air are doubly refracted. The human eye sees the reflection as an arch of brilliant colours which is called a rainbow.
Clouds are collections of water vapour in the various layers of the atmosphere.
Fog and mist are formed, when condensation of the water-vapors in the air near the earth’s surface, takes place upon the dust particles in the air. As a scientist said, ‘A fog is a cloud resting on the earth and a cloud is a fog floating high in the air.’
When the light of the sun or the moon is obscured by another body passing between it and the eye, the sun or the moon is said to be in eclipse.
Let us see what an earthquake is. The crust of our. Lancet is made up of several solid rock faces which are not static. They are moving slowly by millimeters. The thickness of the plates and their depths range from thirty to eighty kilometers below the surface. The huge moving plates are separate from one another. An earthquake occurs when these slowly moving plates clash with one another. The quakes are caused by the release of elastic energy during the movements of the plates. The energy is released in the form of seismic waves or shock waves traveling outward in all directions. The intensity of the quake is measured in the Richter scale devised by a seismologist, C. F. Richter of California, USA. He devised a logarithmic scale which measures the intensity of the quake shock.