Air Class 5 Science DAV Chapter 10 Solutions

A. Fill in the blanks (with answers):

1. The two main gases present in the air are nitrogen and oxygen.

2. Animals need oxygen gas for breathing.

3. Plants use carbon dioxide gas to prepare their own food.

4. The process by which plants prepare their food is called photosynthesis.

5. Ozone gas, present in the atmosphere, protects us from the harmful rays of sunlight.

6. Air containing impurities is called polluted air.

B. Write True or False

1. Pure air is colourless, odourless and tasteless. — True

2. An empty glass bottle contains air. — True

3. Air gets impure due to the presence of nitrogen gas. — False

4. Leaves of a plant look greener before rain. — False

5. Oxygen is required for burning. — True

C. Tick (✔) the correct option:

1. The gas which is present the most in air is —

✔ (b) nitrogen

2. An air pollutant which exists in solid form is —

✔ (c) smoke

3. The gas whose amount varies with weather changes is —

✔ (c) water vapour

4. The gas that gets reduced through the process of photosynthesis is —

✔ (d) carbon dioxide

5. When sulphur dioxide reacts with water and oxygen in air, it results in the production of —

✔ (b) acid rain

D. Answer the following questions in brief:

1. Name the main components of air.

→ The main components of air are nitrogen, oxygen, carbon dioxide, water vapour and dust particles.

2. State the meaning of the term ‘Photosynthesis’.

→ Photosynthesis is the process by which green plants make their own food using sunlight, carbon dioxide and water.

3. State two possible harmful effects of ultraviolet rays.

→ (i) They can cause skin cancer

(ii) They can damage eyes and skin

4. Define the term ‘Air pollutant’.

→ An air pollutant is a harmful substance present in air that makes it impure.

5. Name any two gaseous pollutants present in air.

→ Sulphur dioxide and nitrogen dioxide

6. List any four causes of air pollution.

→ (i) Smoke from vehicles

(ii) Factory emissions

(iii) Burning of garbage

(iv) Firecrackers

E. Answer the following questions:

1. Why is air necessary for animals?

→ Air is necessary for animals because they need oxygen for breathing and survival.

2. How is nitrogen important for plants?

→ Nitrogen helps plants in growth and making proteins, which are necessary for healthy development.

3. How is the balance of oxygen and carbon dioxide in air maintained in nature?

→ Plants take in carbon dioxide and give out oxygen during photosynthesis, while animals breathe in oxygen and release carbon dioxide. This maintains balance in nature.

4. Why is ‘acid rain’ harmful?

→ Acid rain damages plants, buildings, soil and water bodies and harms living organisms.

5. Why should we feel worried about ‘global warming’?

→ Global warming causes increase in Earth’s temperature, melting of glaciers and climate change, which is harmful to life on Earth.

6. Suggest some ways of reducing air pollution.

→ (i) Use public transport

(ii) Plant more trees

(iii) Avoid burning waste 

(iv) Use clean fuels

7. How does planting of trees help in making air cleaner?

→ Trees absorb carbon dioxide and release oxygen, and also trap dust, making the air cleaner.