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class VII

Key Concepts

components of air, greenhouse effect, global warming, layers of atmosphere, weather and climate, temperature Air pressure, pressure belts, wind system, types of rain

essential questions

1. What would happen if atmospheric blanket was missing from earth?
2. If man colonizes on moon, how will he survive the absence of the atmospheric blanket present on earth?
3. Why are plants very important for the life on earth as it exist today?


  1. What is global warming?
  2. What are the various constituents of air?
  3. What is the use of nitrogen in air?
  4. What is air pressure?
  5. What are winds? Give 2 examples.
  6.  What are westerlies and easterlies?

True or false:

  1.  Oxygen is the most important component in air.
  2. Hot air is lighter than cold air, therefore it sinks and cold air rises.
  3.  Greenhouse effect is caused to due to trapping of heat by carbon dioxide.
  4. Earth receives only 1 in 2,000,000,000 parts of the sun’s energy.


  1. What are the various layers of atmosphere. Show with a diagram.
  2. Differentiate between a) Permanent and local winds   b) Seasonal and local winds  c) Troposphere and Mesosphere  d) Stratosphere and Thermosphere   e) Windward and Leeward
  3. Draw a labelled diagram of: a) layers of atmosphere b) Major pressure belt and wind system
  4. What are the various types of rainfall. Explain in detail.


  1. Why is carbon dioxide called a greenhouse gas?
  2. Why is atmosphere important for life on earth?
  3. Why is it said ” if we cut trees then this balance gets disturbed’?
  4. Can you tell the reason why plants use nitrogen?


  1. Why air always moves from high pressure areas to low pressure areas?
  2. Why air pressure is highest at sea level and decreases with height?
  3. How does increase in carbon dioxide affect the earth’s weather and climate? Explain.
  4. Why do astronauts have to wear special protective space suits when in space.
  5. Why are poles colder than equator? Give 2 reasons.


  1. Solve the following: a) If Stratosphere holds ozone then Thermosphere holds_____                                                                                                                   b) Raingauge:_______:: ______: direction of wind                                                                                                                                                                 c) Low pressure:_____ temperature:: High pressure: ____ temperature
  2. Weather changes every day whereas climate remains stable Give a valid reason behind this.