A. Answer the following questions in short:
1. What is the composition of air?
2. Which gas in the atmosphere is essential for respiration?
3. How will you prove that air supports burning?
4. How will you show that air is dissolved in water?
5. Why does a lump of cotton wool shrink in water?
6. List five activities that are possible due to the presence of air.
7. How do animals and plants help each other in the exchange of gases in the atmosphere?
8. Why is the presence of air in the soil essential for plants?
9. What is atmosphere?
10. Why the transparent glass of windows, if not wiped off regularly, appears hazy?
11. Why during an incident of fire, one is advised to wrap a woollen blanket over a burning object?
B. Fill in the Blanks:
1. The layer of air around the earth is known as ………………….. .
2. The component of air used by green plants to make their food, is ………………… .
3. Air is a gaseous …………….. .
4. …………….. is used to inflate tyres of vehicles.
5. The ………………… present in air helps in the formation of clouds.
C. Tick (œ“) the Correct Option:
1. Air is a/an:
(a) mixture
(b) compound
(c) element
(d) none of these
2. Which is the largest component of air?
(a) Oxygen
(b) Nitrogen
(c) Carbon dioxide
(d) Water vapour
3. Air occupies space and has:
(a) colour
(b) smell
(c) mass
(d) none of these
4. ……………….. is a device which measures the air pressure.
(a) Barometer
(b) Thermometer
(c) Anemometer
(d) Ammeter
5. Which gas is released in respiration?
(a) Nitric acid
(b) Carbon monooxide
(c) Carbon dioxide
(d) Sulphur dioxide
6. To release some of the air from the bottle shown in the given diagram, we should:
(a) push the glass further down
(b) tilt the glass
(c) pour more water into the basin
(d) blow bubbles into the glass
D. State True or False:
1. Air has no mass. ………………….
2. Air is a mixture of gases. ……………….
3. Air exerts pressure. ……………….
4. Nitrogen supports burning. ………………
5. Sound can travel only in air. …………….
E. Match the following:
| ‘A’ | ‘B’ |
| 1. Breeze | a. Moving air |
| 2. Storm | b. Slow moving air |
| 3. Smoke | c. Air with very high speed |
| 4. Wind | d. Air with ash particles |
F. Arrange the jumbled words given below in proper form:
1. DILLMWIN ………………..
2. YNOGXE ……………….
3. TUDS ………………..
4. MESKO ………………
G. We should keep the air cleaner and fresher. Air pollution is increasing day by day. Think of some steps you can take to prevent air pollution as much as possible. Discuss with your friends and complete the Table given below:
