Water Cycle


 
 
Concept Explanation
 

Water Cycle

Water Cycle: You know that three-fourth of the earth’s surface is covered by water. Most of the water is cycled between the oceans and the atmosphere through evaporation and rainfall.

  • Evaporation and transpiration :  Water from the surface of oceans, rivers, ponds and lakes into water vapour. Large amount odf water vapour enters in the atmosphere through transpiration by plants.
  • Formation of clouds by condensation : As water vapour rises condensation changes it to clouds. This occur due to the decrease in the temperature of air as we go high up. The air become so cold that the water vapour in it condenses to form tiny droplets.
  • Precipitation : Heavy drops of water in the clouds fall as rains. However, if the temperature is very low, the water droplets freeze in the atmosphere and fall as hail or snow.
  • Back to the water bodies : Thus, water is returned to the water bodies. Such circulation of water is called water cycle.Living beings also cycle water. Some of the rain water seeps into the ground and becomes available to us as groundwater.
  • For example, Animals drink water and throw out water as urine and sweat. Plants lose water to the atmosphere through transpiration, and absorb water from the soil. Although only a very small proportion of the earth’s water resides in living organisms, it is essential for them.
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    Sample Questions
    (More Questions for each concept available in Login)
    Question : 1

    Cloud seeding is a teachnique that induces rain. What does the process involve ?

    Right Option : B
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    Question : 2

    Statement (i) : Sea water changes to water vapours by the process of transpiration in the presence of sunlight.

    Statement (ii) : When sea water changes into water vapour it leaves the dissolved salts behind.

    Right Option : B
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    Question : 3

    Clouds are_____________

    Right Option : C
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