Wind
Moving air is called wind.
Atmosphere
Our earth is surrounded by a thick layer of air called atmosphere.
Atmosphere extends upto less height of about 800 km
Air is a mixture of many gases. The components of air are:
> nitrogen (78 per cent)
> oxygen (21 per cent)
> carbon dioxide (0.03 per cent)
> water vapour and other gases such as argon, helium, neon, etc. (0.97 per cent)
Barometer
The instrument used to measure air pressure is called a barometer.
Q.1 What is atmosphere? How much it extends? What are the main component of atmosphere? Which instrument is used to measure it?
Oxygen for breathing: All living things breathe in air to get oxygen. When we breathe in air, the oxygen from the air is absorbed by the blood and taken to different parts of the body and carbon dioxide is given out.
> Oxygen for burning: Oxygen in the air is needed for burning.
Fertilisers
The chemicals used to increase the fertility of soil is called fertilizer.
Nitrogen is also used to make fertilisers, These fertilisers are added to the soil which helps in the growth of plants.
Photosynthesis: The process of preparing food by the green plants is called photosynthesis. The to prepare food. During this process, the green plants used carbon dioxide and oxygen is given out.
Photosynthesis keeps the percentage of oxygen in the atmosphere, constant.
Q. What is photosynthesis?
> Air also contains water vapour. Water from water bodies evaporates to form water vapour.
Air occupies space –> air balloon
Air Exerts Pressure –> Air exerts pressure in all directions.
Pollution
The presence of unwanted and harmful materials or substances in the ------- is called ------ pollution.
Air Pollution
The presence of unwanted and harmful materials or substances in the air is called air pollution. These harmful substances are called pollutants
Sources of air pollution: may be both natural, or man due to human activities.
Natural Causes of Air Pollution : Air pollutants like dust and smoke may get mixed into air.
Man made Causes of Air Pollution : Air pollutants like burning of fuels, running vehicles
Effects of Air Pollution
Air pollution harms both human health and the environment.
1. Air pollution causes many diseases like asthma, bronchitis, lung cancer and other respiratory disorders.
2. It also leads to irritation of eyes, nose and throat.
3. It damages the protective ozone layer. It protects us from harmful rays of the sun.
4. It kills plants and trees by damaging their leaves.
5. It may cause haze due to which visibility may be reduced.
Q. What is pollution? What is air pollution? What are pollutants? What are the main source of the air pollution? How can we check it? What are the main effects of air pollution ?
Deforestation
Cutting down of trees on a large scale is called deforestation.
It increases amount of carbon dioxide in the air.
Acid Rain
Pollutant gases like sulphur dioxide and nitrogen dioxide get mixed with rain water, form acids and fall on the earth. This is called acid rain.
Acid rain damages buildings, monuments, iron structures such as bridges, pillars, etc., leaves of trees and contaminate lakes, rivers, ponds, etc.
The white colour of the Taj Mahal located in Agra is turning yellowish due to air pollution.
The industries around the Taj Mahal have been ordered to use cleaner fuels like CNG by the Supreme Court of India.
Q. What is acid rain? How it is harmful for us?
SPM = Suspended Particulate Matter
CNG = Compressed Natural Gas
Renewable
Which can be used again and again
A. Fill in the blanks.
1. The atmosphere extends upto a height of ........... .
2 ............. is needed for burning.
3. Plants get nitrogen from ............ .
4. Air exerts .............. in all directions.
Ans. 1. 800 km. 2. Oxygen 3. Soil 4. Pressure
B. Write True or False.
1. We can live without air. F
2. Air consists of oxygen and nitrogen. F
3. Air has mass and occupies space. T
4. The most plentiful gas in the atmosphere is carbon dioxide. F
5. The percentage of oxygen in the air keeps changing. F
Ans. 1. F 2. F 3. T 4. F 5. F
C. Tick (✔) the correct answer.
1. Which of these gases is present in highest amount in air?
(a) Nitrogen
(b) Oxygen
(c) Carbon dioxide
(d) Helium
Ans. (a) Nitrogen
2. Which of these gases controls fire?
(a) Nitrogen
(b) Oxygen
(c) Both nitrogen and oxygen
(d) None of these
Ans. (d) None of these
3. What is the percentage of oxygen gas in the air?
(a) 71
(b) 21
(c) 78
(d) 0.03
Ans. (b) 21
4. Air pollution can
(a) cause irritation of eyes, nose and throat
(b) lead to depletion of ozone layer
(c) damage the leaves of plants
(d) all of these
Ans. (d) all of these
5. Which of these is/are the properties of air?
(a) Air has no mass
(b) Air does not occupy space
(c) Air exerts pressure
(d) None of these
Ans. (c) Air exerts pressure
D. Answer the following questions.
1. What is the composition of air?
Ans. Air is a mixture of many gases, water vapour and dust particles. The nitrogen (78 per cent), oxygen (21 per cent), carbon dioxide (0.03 per cent), water vapour and other gases such as argon, helium, neon, etc. (0.97 per cent)
2. How is oxygen useful to us?
Ans. All living things breathe in air to get oxygen. When we breathe in air, the oxygen from the air is absorbed by the blood and taken to different parts of the body and carbon dioxide is given out.
Oxygen for burning: Oxygen in the air is needed for burning.
3. How is carbon dioxide useful to plants?
Ans. The process of preparing food by the green plants is called photosynthesis with the help of carbon dioxide. During this process, the green plants used carbon dioxide and oxygen is given out.
4. How is nitrogen useful?
Ans. Nitrogen is used to make fertilisers, These fertilisers are added to the soil which helps in the growth of plants.
5. What are the properties of air?
Ans. The air shows the following properties:
1. Air is a mixture of many gases, water vapour and dust particles.
2. Air has mass and occupies space.
3. Air occupies space.
4. Air exerts pressure in all directions.
6. What is air pollution? Write two main man-made causes of air pollution.
Ans. The presence of unwanted and harmful materials or substances in the air is called air pollution.
Man made Causes of Air Pollution : Air pollutants like burning of fuels, running vehicles
7. Write four effects of air pollution.
Ans. Effects of Air Pollution
Air pollution harms both human health and the environment.
1. Air pollution causes many diseases like asthma, bronchitis, lung cancer and other respiratory disorders.
2. It also leads to irritation of eyes, nose and throat.
3. It damages the protective ozone layer. It protects us from harmful rays of the sun.
4. It kills plants and trees by damaging their leaves.
5. It may cause haze due to which visibility may be reduced.
8. Write four ways to reduce air pollution.
Ans. Control of Air Pollution:
1. We should plant more trees as they remove carbon dioxide from the air and release oxygen into the atmosphere.
2. Automobiles or vehicles should be checked regularly so that they do not release harmful gases.
3. We should use non polluting or renewable forms of energy like the sun and wind.
4. We should use non-polluting fuels like CNG for cars and buses.
5. To walk down to the nearby market or use a bicycle; instead of going a car or scooter.
6. Public transport should be used.
E. Find and encircle the words in the wordsearch with the help.
1. Blanket of air surrounding the earth
2. Moving air
3. Gas needed for burning
4. A disease caused due to air pollution
5. An instrument used to measure air pressure
6. The component of air used to make fertilisers
Ans. 1. Atmosphere 2. Wind 3. Oxygen 4. Asthma 5. Barometer 6. Nitrogen
🌺🌺🌺🪷🪷 For Test 🪷🪷🌺🌺🌺
*Part 01*
Q.1 What is atmosphere? How much it extends? What are the main component of atmosphere? Which instrument is used to measure it?
Ans.
Atmosphere
★ Our earth is surrounded by a thick layer of air called atmosphere.
★ Atmosphere extends upto height of about 800 km
★ Air is a mixture of many gases. The components of air are:
> nitrogen (78 per cent)
> oxygen (21 per cent)
> carbon dioxide (0.03 per cent)
> water vapour and other gases such as argon, helium, neon, etc. (0.97 per cent)
★ The instrument used to measure air pressure is called a barometer.
Q.2 What is pollution? What is air pollution? What are pollutants? What are the main source of the air pollution? How can we check it? What are the main effects of air pollution ?
Ans.
★ Pollution
The presence of unwanted and harmful materials or substances in the ------- is called ------ pollution.
★ Air Pollution
The presence of unwanted and harmful materials or substances in the air is called air pollution. These harmful substances are called pollutants.
★ The unwanted and harmful materials or substances presence in the air is called air pollutants
★ Sources of air pollution: Sources of air pollution may be both natural, or man made due to human activities.
Natural Causes of Air Pollution : Air pollutants like dust and smoke may get mixed into air.
Man made Causes of Air Pollution : Air pollutants like burning of fuels, running vehicles
Human activities which pollute air
★ Burning of wood, coal, kerosene, etc. gives out carbon dioxide and other toxic fumes.
★ Factories and mills give out smoke containing carbon dioxide and other harmful gases.
★ Vehicles like cars, buses, trucks, etc. also emit oxides of carbon, nitrogen and lead.
★ All these harmful gases and smoke make the air dirty or polluted. The presence of unwanted and harmful things in air is causing air pollution.
★ Effects of Air Pollution
Air pollution harms both human health and the environment.
1. Air pollution causes many diseases to all living beings like asthma, bronchitis, lung cancer and other respiratory disorders.
2. It also leads to causes of irritation of eyes, nose and throat.
3. It damages the protective ozone layer. It protects us from harmful rays of the sun.
4. It kills plants and trees by damaging their leaves.
5. It may cause haze due to which visibility may be reduced.
6. It increases amount of carbon dioxide in the air. Increasing of carbon dioxide level in the air leads to globe warming. It is a threat to all living beings.
*Part 02*
Q.1 What is photosynthesis?
Ans.
Photosynthesis: The process of preparing food by the green plants is called photosynthesis. The to prepare food. During this process, the green plants used carbon dioxide and oxygen is given out.
Photosynthesis keeps the percentage of oxygen in the atmosphere, constant.
Q.2 What is acid rain? How it is harmful for us?
Ans.
Acid Rain
Pollutant gases like sulphur dioxide and nitrogen dioxide get mixed with rain water, form acids and fall on the earth. This is called acid rain.
Acid rain damages buildings, monuments, iron structures such as bridges, pillars, etc., leaves of trees and contaminate lakes, rivers, ponds, etc.
Q.3 What is wind?
Ans.
Wind
Moving air is called wind.
Q.4 What is deforestation and afforestation ?
Ans.
Deforestation
Cutting down of trees on a large scale is called deforestation.
It increases amount of carbon dioxide in the air.
Q.5 What is fertilizer?
Ans.
Fertilisers
The chemicals used to increase the fertility of soil is called fertilizer.
Nitrogen is also used to make fertilisers, These fertilisers are added to the soil which helps in the growth of plants.
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