Air Around Us Class 6 Questions and Answers

💨 Air Around Us Class 6 Questions and Answers

NCERT Chapter 15 with Detailed Solutions

Master Air Around Us for Class 6 Science with comprehensive questions and answers covering the composition of air, atmosphere, oxygen cycle, air pollution, and the importance of air for life. Each answer is explained in simple, student-friendly language for CBSE exams.

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💨

Air Around Us — Questions & Answers

NCERT Class 6 Science Chapter 15

📘 Quick Reference: Air Around Us

Air: A mixture of gases that surrounds the Earth. It is colourless, odourless, and transparent. We cannot see air, but we can feel it.
Atmosphere: The thin layer of air surrounding the Earth. It extends up to about 600 km above the Earth's surface. It protects us from harmful sun rays and helps regulate temperature.
Composition of Air:
- Nitrogen (N₂): About 78% — the largest component. Does not support burning.
- Oxygen (O₂): About 21% — essential for respiration and burning.
- Carbon Dioxide (CO₂): About 0.03% — used by plants for photosynthesis.
- Other gases: Argon, neon, helium, and water vapour (about 1% together).
- Dust particles and smoke: Present in small amounts; can be harmful.
Oxygen: Essential for respiration in all living organisms. It also supports burning. Plants produce oxygen during photosynthesis.
Carbon Dioxide: Used by green plants to make food through photosynthesis. Released during respiration and burning.
Water Vapour: The gaseous form of water present in air. The amount of water vapour in air is called humidity. It is essential for the water cycle.
Nitrogen: Makes up most of the air but does not support burning. Plants need nitrogen for growth (through nitrogen fixation).
Air in Water: Air is dissolved in water. Aquatic animals use this dissolved oxygen to breathe (through gills).
Air in Soil: Soil has small air pockets between particles. Earthworms and other soil organisms breathe this air.
Wind: Moving air is called wind. It is used by windmills to generate electricity and by sailors to move boats.
Balance of Oxygen and Carbon Dioxide: Maintained by the cycle of photosynthesis (plants release oxygen) and respiration (animals release carbon dioxide).
Air Pollution: When harmful substances like smoke, dust, and poisonous gases mix with air, it becomes polluted. This harms living beings.

Key Points Summary Table:

Concept	Key Point
Main Component	Nitrogen (78%)
Gas for Respiration	Oxygen
Gas for Photosynthesis	Carbon Dioxide
Gas that Supports Burning	Oxygen
Gas that Does NOT Support Burning	Nitrogen & Carbon Dioxide
Atmosphere Layer	~600 km thick
Humidity	Water vapour in air

💡 Study Tip

Try a simple experiment to see air around you. Take an empty glass and push it upside down into a bucket of water. You will notice that water does not enter the glass. This is because the glass is not empty — it is filled with air! Tilt the glass slightly, and you will see bubbles of air coming out. This proves that air occupies space. Also, observe how a candle burns inside a covered glass — it goes out after some time because the oxygen inside is used up.

Question 1

What is air?

✅ Answer:

Air is a mixture of gases that surrounds the Earth and is essential for life.

Question 2

Can we see air?

✅ Answer:

No, we cannot see air, but we can feel its presence when it moves (wind).

Question 3

What is the atmosphere?

✅ Answer:

The layer of air surrounding the Earth is called the atmosphere.

Question 4

Which gas is the major component of air?

✅ Answer:

Nitrogen is the major component of air, making up about 78% of it.

Question 5

What is the percentage of oxygen in air?

✅ Answer:

Oxygen makes up about 21% of the air.

Question 6

Which gas is essential for respiration?

✅ Answer:

Oxygen is essential for respiration in all living organisms.

Question 7

Which gas supports burning?

✅ Answer:

Oxygen supports burning (combustion).

Question 8

Which gas do plants use to make food?

✅ Answer:

Plants use carbon dioxide to make food through photosynthesis.

Question 9

What is the amount of carbon dioxide in air?

✅ Answer:

Carbon dioxide is present in a very small amount, about 0.03% of the air.

Question 10

What is wind?

✅ Answer:

Moving air is called wind.

Question 11

Name two activities that need air.

✅ Answer:

Respiration and photosynthesis are two activities that need air.

Question 12

What is humidity?

✅ Answer:

The amount of water vapour present in the air is called humidity.

Question 13

Which gas is released during respiration?

✅ Answer:

Carbon dioxide is released during respiration.

Question 14

How do fish breathe in water?

✅ Answer:

Fish breathe using gills to take in oxygen dissolved in water.

Question 15

What is air pollution?

✅ Answer:

The presence of harmful substances like smoke, dust, and poisonous gases in air is called air pollution.

Question 16

Name one natural source of air pollution.

✅ Answer:

Volcanic eruptions are a natural source of air pollution.

Question 17

What is the function of the ozone layer?

✅ Answer:

The ozone layer protects us from the harmful ultraviolet (UV) rays of the sun.

Question 18

Why do we feel suffocated in a closed room with a burning fire?

✅ Answer:

Burning fire uses up oxygen and produces carbon dioxide, causing suffocation.

Question 19

Name any two musical instruments that use air.

✅ Answer:

Flute and trumpet are musical instruments that use air.

Question 20

Why do wet clothes dry faster on a windy day?

✅ Answer:

Wind speeds up evaporation of water from wet clothes, making them dry faster.

Question 21

What is the use of windmills?

✅ Answer:

Windmills use wind energy to generate electricity and pump water.

Question 22

Why do mountaineers carry oxygen cylinders?

✅ Answer:

At high altitudes, air becomes thinner and has less oxygen, so mountaineers carry oxygen cylinders.

Question 23

What happens to a burning candle when covered with a glass tumbler?

✅ Answer:

The candle goes out because the oxygen inside the tumbler is used up.

Question 24

Is air present in soil?

✅ Answer:

Yes, air is present in the spaces between soil particles.

Question 25

Why do earthworms come out during heavy rains?

✅ Answer:

Rainwater fills the air spaces in soil, so earthworms come out to breathe air.

Question 26

Name the gas used in food packaging.

✅ Answer:

Nitrogen is used in food packaging to keep food fresh.

Question 27

What is the direction of air in a weathercock?

✅ Answer:

A weathercock shows the direction of the wind.

Question 28

What are the properties of air?

✅ Answer:

Air is colourless, odourless, transparent, occupies space, has mass, and exerts pressure.

Question 29

Why do we breathe through our nose?

✅ Answer:

Our nose has fine hair and mucus that filter dust particles from the air.

Question 30

Name any two uses of air in daily life.

✅ Answer:

Air is used for breathing and for inflating tires and balloons.

Question 1

What is the composition of air? Give the approximate percentages of its main components.

✅ Answer:

Air is a mixture of gases. Its main components are:

Nitrogen: About 78%
Oxygen: About 21%
Carbon dioxide: About 0.03%
Other gases: Argon, neon, helium, and water vapour (about 1%)

It also contains dust particles and smoke in small amounts.

Question 2

Why is air considered a mixture?

✅ Answer:

Air is considered a mixture because it contains two or more gases (nitrogen, oxygen, carbon dioxide, etc.) that are not chemically combined. Each gas retains its own properties, and the composition of air can vary from place to place.

Question 3

How does oxygen become available to animals living in water?

✅ Answer:

Air is dissolved in water. Aquatic animals like fish use their gills to take in this dissolved oxygen from the water for respiration.

Question 4

How does oxygen become available to animals living in soil?

✅ Answer:

Soil contains air pockets between its particles. Animals like earthworms and insects living in the soil breathe this air through their skin or special organs.

Question 5

How is the balance of oxygen and carbon dioxide maintained in the atmosphere?

✅ Answer:

The balance is maintained by two processes:

Respiration: Animals and plants take in oxygen and release carbon dioxide.
Photosynthesis: Green plants take in carbon dioxide and release oxygen during the day.

This natural cycle keeps the levels of both gases stable.

Question 6

Why does a burning candle go out when covered with a glass tumbler?

✅ Answer:

A burning candle needs oxygen to burn. When covered with a glass tumbler, the supply of oxygen inside is limited and gets used up quickly. Without oxygen, the candle goes out.

Question 7

How will you show that air is dissolved in water?

✅ Answer:

Take some water in a pan and heat it slowly. Before the water starts boiling, you will see tiny bubbles forming on the inner surface of the pan. These bubbles are of air dissolved in water. This shows that air is present in water.

Question 8

Why does a lump of cotton wool shrink in water?

✅ Answer:

A lump of cotton wool has air trapped between its fibres. When dipped in water, the air is replaced by water, causing the fibres to stick together and the lump to shrink.

Question 9

Why do we feel suffocated when we burn something in a closed room?

✅ Answer:

Burning in a closed room uses up the oxygen and produces carbon dioxide. Since the room is closed, fresh air cannot enter. Breathing this air with less oxygen and more carbon dioxide causes suffocation.

Question 10

Why do we breathe through our nose and not our mouth?

✅ Answer:

Our nose has fine hair and mucus that filter out dust particles from the air we breathe. This prevents harmful particles from entering our lungs. Our mouth does not have this filtering system, so breathing through the mouth can be harmful.

Question 11

What is the importance of the atmosphere for life on Earth?

✅ Answer:

The atmosphere is important because:

It provides air for breathing.
It regulates temperature by trapping heat from the sun.
It contains the ozone layer that protects us from harmful UV rays.
It causes weather changes like rain and wind.

Question 12

Why do mountaineers carry oxygen cylinders while climbing high mountains?

✅ Answer:

At high altitudes, the air becomes thinner and there is less oxygen available for breathing. To avoid breathing problems and to get enough oxygen, mountaineers carry oxygen cylinders with them.

Question 13

How does air help in the water cycle?

✅ Answer:

Water evaporates from oceans, rivers, and lakes and rises as water vapour in the air. The water vapour cools and condenses to form clouds, which then bring rain. This cycle is essential for the water cycle on Earth.

Question 14

What are the harmful effects of air pollution?

✅ Answer:

Air pollution causes:

Respiratory problems like asthma and bronchitis.
Heart diseases due to harmful gases.
Damage to plants and crops.
Acid rain which harms buildings and aquatic life.

Question 15

How can we reduce air pollution?

✅ Answer:

We can reduce air pollution by:

Planting more trees.
Using public transport or carpooling.
Avoiding burning of garbage and firecrackers.
Using clean energy like solar and wind.
Regular checking of vehicle emissions.

Question 1

Explain the composition of air with a pie chart description. Why is air important for life?

✅ Answer:

Composition of Air:

Air is a mixture of several gases and particles. The main components are:

Nitrogen (78%): The largest component. It does not support burning.
Oxygen (21%): Essential for respiration and burning.
Carbon Dioxide (0.03%): Used by plants for photosynthesis.
Other gases (about 1%): Argon, neon, helium, water vapour.
Dust and smoke: Small particles present in air.

Imagine a pie chart: about 3/4 is nitrogen, about 1/5 is oxygen, and a very tiny slice is carbon dioxide and other gases.

Importance of Air for Life:

Respiration: All living things need oxygen from air to breathe.
Photosynthesis: Plants use carbon dioxide from air to make food.
Temperature Regulation: The atmosphere traps heat and keeps Earth's temperature stable.
Protection: The ozone layer in the atmosphere protects us from harmful UV rays.
Weather: Water vapour in air causes rain, snow, and other weather conditions.
Movement: Wind helps in sailing, flying, and seed dispersal.

Question 2

Describe an activity to prove that air occupies space.

✅ Answer:

Activity: Air Occupies Space

Materials needed:

A bucket or large container
Water
An empty glass or bottle

Procedure:

Fill the bucket with water.
Take the empty glass and push it upside down straight into the water.
Observe what happens.
Now, tilt the glass slightly while it is still in water.

Observation:

When you push the glass upside down, water does not enter the glass.
When you tilt the glass, bubbles of air come out, and water starts entering.

Conclusion:
The glass was not empty — it was filled with air. The air prevented water from entering. This proves that air occupies space.

Question 3

How do plants and animals help each other in maintaining the balance of oxygen and carbon dioxide in the atmosphere?

✅ Answer:

Plants and animals help each other through two important processes:

1. Respiration (Animals and Plants):
All living organisms, including plants and animals, take in oxygen from the air and release carbon dioxide during respiration.

2. Photosynthesis (Green Plants):
Green plants use carbon dioxide and water, in the presence of sunlight and chlorophyll, to make their food. During this process, they release oxygen into the air.

How They Help Each Other:

Animals release carbon dioxide, which plants need for photosynthesis.
Plants release oxygen, which animals need for respiration.

This continuous exchange keeps the levels of oxygen and carbon dioxide balanced in the atmosphere.

Question 4

Explain how oxygen becomes available to animals living in water and soil.

✅ Answer:

Oxygen for Animals in Water:
Air dissolves in water. Aquatic animals like fish use their gills to take in this dissolved oxygen from the water. The gills absorb oxygen and release carbon dioxide.

Oxygen for Animals in Soil:
Soil contains air pockets between its particles. Animals like earthworms and insects living in the soil use this air for breathing.

Special Case - Earthworms:
Earthworms breathe through their moist skin. During heavy rains, water fills the air spaces in soil, so earthworms come out to breathe air directly.

This shows that air is present everywhere — in water, in soil, and around us.

Question 5

What is air pollution? What are its causes and effects? How can we reduce it?

✅ Answer:

Air Pollution:
Air pollution is the presence of harmful substances (pollutants) in the air that can harm living beings and the environment.

Causes of Air Pollution:

Vehicles: Smoke from cars, buses, and trucks.
Industries: Harmful gases and smoke from factories.
Burning of fuels: Coal, wood, and petrol release smoke.
Burning of garbage: Releases toxic gases.
Natural causes: Volcanic eruptions, dust storms.

Effects of Air Pollution:

Health problems: Asthma, bronchitis, lung cancer.
Damage to plants: Affects growth and crop yield.
Acid rain: Harmful to buildings, soil, and water life.
Global warming: Due to increased greenhouse gases.

How to Reduce Air Pollution:

Plant more trees — they absorb carbon dioxide.
Use public transport or carpool.
Use clean energy like solar and wind power.
Avoid burning garbage and firecrackers.
Regular maintenance of vehicles.

Question 6

List five activities that are possible due to the presence of air.

✅ Answer:

Five activities that are possible due to air are:

1. Respiration: All living organisms breathe in oxygen from the air to release energy.

2. Photosynthesis: Plants use carbon dioxide from air to make their food.

3. Burning (Combustion): Fire needs oxygen from air to burn.

4. Movement of Sailing Boats and Aeroplanes: Wind helps in the movement of sailing yachts, and air provides lift to aeroplanes.

5. Generation of Electricity: Windmills use wind (moving air) to generate electricity.

Other activities include: cloud formation, seed dispersal, winnowing, and playing musical instruments like the flute.

Question 7

Explain the properties of air.

✅ Answer:

Properties of Air:

1. Air is Colourless and Transparent: We can see through air. It has no colour.

2. Air is Odourless: Air has no smell.

3. Air Occupies Space: Air fills all empty spaces. A glass pushed upside down into water does not let water enter because it is filled with air.

4. Air Has Mass (Weight): A balloon filled with air weighs more than an empty balloon.

5. Air Exerts Pressure: The weight of air presses down on us. This is called air pressure.

6. Air Can Be Compressed: Air can be squeezed into smaller spaces, like in a bicycle pump.

7. Air Dissolves in Water: Air is present in water, which aquatic animals use for breathing.

Question 8

Describe an experiment to show that air is necessary for burning.

✅ Answer:

Experiment: Air is Necessary for Burning

Materials needed:

Two candles of the same length
A matchbox
A glass tumbler

Procedure:

Place both candles on a table and light them.
Cover one candle with the glass tumbler.
Observe both candles carefully.

Observation:

The uncovered candle continues to burn.
The covered candle goes out after some time.

Conclusion:
The covered candle went out because the oxygen inside the tumbler was used up. The uncovered candle kept burning because it got a continuous supply of air (oxygen). This proves that air is necessary for burning.

Question 9

What are the uses of air in our daily life?

✅ Answer:

Uses of Air in Daily Life:

Breathing: All living organisms need oxygen from air to breathe and survive.
Photosynthesis: Plants use carbon dioxide from air to make their food.
Burning: Oxygen in air is needed for burning fuels like wood, coal, and LPG.
Transportation: Air helps in the movement of sailing boats, aeroplanes, and hot air balloons.
Electricity Generation: Windmills use moving air to generate electricity.
Inflating: Air is used to fill tires, balloons, and footballs.
Music: Instruments like flute, trumpet, and saxophone produce sound using air.
Drying: Air helps in drying clothes and wet surfaces.
Water Cycle: Water vapour in air is essential for rain and the water cycle.

Question 10

Why do we see dust particles in a beam of sunlight entering a dark room? What are the harmful effects of dust?

✅ Answer:

Why We See Dust Particles:
Air contains tiny dust particles. When a beam of sunlight enters a dark room, the light hits these particles and scatters. This scattered light reaches our eyes, making the dust particles visible as tiny floating specks.

Harmful Effects of Dust:

Respiratory Problems: Inhaling dust can cause coughing, sneezing, and lung diseases.
Allergies: Dust can trigger allergies and asthma attacks.
Reduced Visibility: Dust in air can reduce visibility, causing problems in traffic.
Damage to Electronic Devices: Dust can settle on and damage computers and other electronics.

How to Protect Ourselves:

Wear masks in dusty environments.
Keep windows closed during dusty weather.
Plant trees to reduce dust in air.

📘 Quick Revision: Air Around Us

Air: Mixture of gases; colourless, odourless, transparent.
Composition: Nitrogen (78%), Oxygen (21%), Carbon dioxide (0.03%), Other gases (1%).
Atmosphere: Layer of air surrounding Earth, ~600 km thick.
Oxygen: Needed for respiration and burning.
Carbon Dioxide: Needed by plants for photosynthesis.
Nitrogen: Major component; does not support burning.
Water Vapour: Causes humidity and weather changes.
Air in Water: Dissolved oxygen for aquatic animals.
Air in Soil: Air pockets for soil organisms.
Balance: Maintained by respiration and photosynthesis.
Air Pollution: Harmful substances in air; causes health problems.