March 16, 2014

PRECIPITATION - Different Types of Precipitatiom

When condensation takes place rapidly and continuously, the condensed particles grow in size. The air is unable to hold them and they fall on the surface of the earth. The condensation of water-vapour in the air in the form of water droplets or ice crystals and their falling on the earth’s surface is known as precipitation. Rainfall is the most common form of precipitation. Other forms of precipitation arc snowfall, sleet, hail. Etc.

Different Types of Precipitation
1. Rain — Rain is the most important form of precipitation. When the cloud rises up or is blown to a cooler region the small droplets of water become colder and they join together to form bigger drops. These drops cannot float in the air. They fall through the air on the ground as rain. Three conditions are necessary for the formation of rain drops: (i) There should be evaporation, (ii) There should be condensation, and (iii) There should be dust particles in the air.

2. Snowfall — When the temperature of the air reaches below the freezing point, the water-vapour in the air condenses directly into crystals and later on into flakes of snow without passing through the liquid form. When these flakes of snow fall on the ground it is called the snowfall.

3. Hail — Sometimes the rain-drops may reach colder regions where the temperature is far below the freezing point. In that case the rain-drops get frozen but a strong upward air current throws them back. It may happen more than once till the weight of these frozen drops is more than the upward thrust of the air and then they fall on the earth in the form of hailstones. They fall more often in summer than in winter. Hailstones can cause great damage to standing crops, animals and human beings.


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