Air Around us

Q1. Fill in the blanks.

                           i.        We cannot see air but we can feel it.

                          ii.        The blanket of air surrounding the earth is known as atmosphere.

                         iii.        Oxygen is essential for supporting life on the earth.

                         iv.        Air occupies space.

                          v.        Winnowing is more effective in moving air.

Q2. True/False

                           i.        Air is found everywhere. True

                          ii.        Soil does not contain air. False

                         iii.        The moving air makes it possible for you to fly your kite. True

                         iv.        Carbon dioxide supports burning of a candle. False

                          v.        Birds, bats and insects can fly due to the presence of air. True

Q3. Which is the major component of air?

Ans. Nitrogen

Q4. What percentage of air is nitrogen?

Ans. 78%

 
Q5. Which gas is important for burning to occur?

Ans. Oxygen

 
Q6. What percentage of air is oxygen?

Ans. Under 21%

Q7. What is the name of the gas we breathe in?

Ans. Oxygen

Q8. What is the name of the gas we breathe out?

Ans. Carbon dioxide

Q9. Which device is used to harness wind energy to generate electricity?

Ans. Wind mill

Q10. What makes firki to rotate?

Ans. Moving air makes firki to rotate.

Q11. What is wind?

Ans. Air in motion is called wind.

Q12. What may even uproot trees and blow off the rooftops?

Ans. The high velocity winds or Storms

 
Q13. What are those tiny shining particles in the beam of sunlight?

Ans. Those tiny shining particles are the dust particles present in the air.

Q14. What do you understand by atmosphere?

Ans. The envelope of air that surrounds the earth is known as atmosphere.

Q15. From where does oxygen come in the air?

Ans. Plant release oxygen in the air by the process of photosynthesis.

Q16. Which component of air used by green plants to make their food?

Ans. The component of air used by green plants to make their food is carbon dioxide.

Q17. Why air is called a mixture of gases?

Ans. Air is called mixture of gases because it is made up of many different gases.

Q18. Why pages of an open book begin fluttering when the fan is switched on?

Ans. Pages of an open book begin fluttering when the fan is switched on because of air.

Q19. What is air made up of?

Ans. Air is a mixture of nitrogen, oxygen, carbon dioxide, water vapor and a few other gases. Some dust particles may also be present in it.

Q20. How do we feel the presence of air?

Ans. We cannot see the air around us but we can feel its presence when the leaves of the trees rustle or the clothes hanging on a clothes-line sway.

Q21. Why carbon dioxide gas is used in fire extinguishers?

Ans. Carbon dioxide gas is used in fire extinguishers because it does not support combustion.

Q22. Prove that soil contains air with help of an activity.

Ans. Take some soil in a glass. Then add water to it, the air bubbles comes out of the soil. These bubbles indicate the presence of air in the soil.