1. Fill in the blanks
a. The blanket of gases around Earth is called atmosphere.
b. Distilled water is used in car batteries, science experiments and medicines.
c. Evaporation method can be used to get salt from salt water solution.
d. Chlorine gas is used to kill germs present in water.
2. Tick (√) the correct word.
a. Air is made up of 21 percent of oxygen and it also contains dust, water vapour etc.
b. Water leaving the sediment behind is called decantation.
c. The air pressure is measured using barometer.
3. Define.
a. Humidity: The amount of water vapor present in the air.
b. Atmospheric pressure: The pressure exerted by the weight of the atmosphere on the Earth’s surface.
c. Sedimentation: The process by which solid particles settle at the bottom of a liquid due to gravity.
4. Think and answer.
a. Mountaineers carry oxygen cylinders with them because at high altitudes, the air is thinner and contains less oxygen, making it difficult to breathe.
b. If there is no oxygen in the air, living organisms would not be able to respire and would die; combustion and most chemical reactions requiring oxygen would also stop.
c. Suppose you don’t have a water filter at home. You can use boiling to purify water, or let it settle and then decant the clear water, followed by adding a few drops of chlorine or using alum to remove impurities.
Parent Tip: Review the logic above to help your child master the concept of water in the atmosphere worksheet answers.
