Available Answers

1. 1.

   Match the following.

   1. The mild form of fog	a. Sleet
   2. Pellets of frozen rain	b. Mist
   3. Water changes from liquid to gas	c. Frost
   4. Rain containing some ice	d. Condensation
   5. The conversion of gas to a liquid	e. Evaporation
   	f. Hail

    

2. 2.

   Write true or false.

   1. Boiling is the simplest method to purify water.
   2. Germs are useful living organisms in water.
   3. Chlorine is a chemical that is added to water to kill germs present in it.
   4. We should always purify water before drinking.
   5. Hot air sinks and cold air rises up in the air.
3. 3.

   Read the clues and complete the crossword.

   Across
   2. This is the layer of air that surrounds the earth.
   7. The process in which water gets heated and changes into water vapour.
   8. The process of evaporation, condensation and precipitation that takes place in nature is known as

   Down
   1. During the right, the cool air from the land moves in towards the sea and takes its place. This is called
   3. When th earth spins on its won axis, the movement is known as
   4. The simples method to purify water is
   5. This causes weather to change from time to time
   6. This is the state of the atmosphere of a place at a particular time in relation to heat, cloudiness, dryness, sunshine, wind, and rain.

   

4. 4.

   Tick(√) the correct answer.

   1. The earth moves around the sun in its fixed orbit. This is called
      1. revolution
      2. rotation
      3. season
      4. atmosphere
   2. The cool air from the sea moving in towards the land and taking its place is known as
      1. thunderstorm
      2. land breeze
      3. sea breeze
      4. storm
   3. Which process is not used to make the water fit for use?
      1. Boiling
      2. Sedimentation
      3. Evaporation
      4. Filtration
   4. __________ is any form of liquid or solid water particles that fall from the atmosphere and reach the surface of the earth.
      1. Condensation
      2. Evaporation
      3. Mist
      4. Precipitation
   5. In the __________ method, unclean water is passed through filter paper.
      1. chlorination
      2. boiling
      3. filtration
      4. decantation
5. 5.

   Fill in the blanks.

   1. __________ is an invisible mixture of gases such as oxygen, carbon dioxide, water vapour, smoke and dust.
   2. The process in which water changes from liquid to gas is called __________.
   3. Thin layer of ice crystals that form due to very cold weather is known as __________.
   4. The impurities that are suspended in water and can be seen are known as __________ impurities.
   5. __________ is a chemical that is added to water to kill germs present in it.
6. 6.

   Define revolution.