Available Answers

1. 1.

   Fill in the blanks.

   1. We live in the _______________ layer of the earth.
   2. _______________ gas is needed for breathing and burning.
   3. _______________ gas is filled in air balloons.
   4. _______________ is higher in coastal areas.
   5. The air contains 78% of _______________ gas.
2. 2.

   Tick (√) the correct answer.

   1. Germs/Mud are insoluble impurities present in water.
   2. Chlorination helps to remove soluble/insoluble impurities in water.
   3. Boiling /Filtration of water kills germs.
   4. The mud that settles at the bottom of a container is called a sediment/layer.
   5. A chemical used to kill germs present in the water is chorine/alum.
3. 3.

   Complete the flow chart given below.

   

4. 4.

   Choose the correct answer.

   1. The thick blanket of air that surrounds our planet is called _______________.
      1. atmosphere
      2. lithosphere
      3. biosphere
   2. Ozone layer is a part of _______________.
      1. troposphere
      2. stratosphere
      3. thermosphere
   3. The gas used to fill an air balloon is  _______________.
      1. argon
      2. neon
      3. helium
   4. Insoluble impurities present in water can be removed by _______________.
      1. boiling 
      2. chlorination
      3. filtration
   5. The gas that helps in burning is _______________.
      1. oxygen
      2. carbon dioxide
      3. nitrogen
5. 5.

   Underline the analogy and fill in the blanks.

   1. 21% : ____________ :: 78% : Nitrogen
   2. Germs : ____________ : : Mud : Sedimentation
   3. Troposphere: Weather changes :: ____________ : Helps radio to work
   4. Salts : ____________ :: Mud : Insoluble impurities
   5. ____________ : Electric bulb :: Neon: Glow signs
6. 6.

   Fill in the blanks.

   1. _____________ is called the universal solvent.
   2. The earth's _____________ holds the atmosphere in place.
   3. _____________ is a chemical added to water to kill germs.
   4. Jet planes fly in the ______________ layer of the atmosphere.
   5. In the ______________ season, humidity is high.