Air is an invisible mixture of gases that surrounds the Earth and supports life. Although we cannot see it, air plays an essential role in breathing, weather, combustion, and maintaining the balance of our environment. From oxygen required for respiration to nitrogen that helps maintain atmospheric stability, each component has its own significance.

This article is to help students understand the composition and properties of air and importance of air in a easy-to-understand manner with 8 downloadable practice worksheets for the kids to make it more understandable.

What is Air
The Composition of Air
The Properties of Air
Facts About Composition and Properties of Air

What is Air

Air is mostly gas. It is all around us. We can not see it, but we can feel it when air blows as wind. We breath in air which is oxygen and release carbon dioxide. Hence, can say that air is a mixture of gases.

Why Do We Need Air?

Air is vital for life and contains oxygen, which we need to breathe and survive. The main reason plants, animals, and humans all need air is different:

Image of importance of air

For breathing: Our lungs absorb oxygen from the air to help function properly in our body.
For plants: They use carbon dioxide in the air to produce food by photosynthesis (Learn more on photosynthesis here).
For Energy: Oxygen is crucial for burning fuels that enable the movement of vehicles to promote activities across the globe. Air also acts as a protective shield from the harmful rays of the sun and maintains the perfect temperature for life on Earth.

Test your Understanding:

1. Why do humans and animals need air to survive?

a) For protection from the sun

b) To obtain oxygen for breathing

c) To intake carbon dioxide

2. What would happen if there were no air on Earth?

a) Humans would float in space
b) Living organisms would not survive
c) It would always be night time

The Composition of Air

Air is a mixture of gases that comes to envelop the Earth and gives support to life. Though this air appears to be transparent and weightless, it is comprised of several gases; each one plays an important role in maintaining a balance on our planet.

Air is a mixture of various gases. Let’s break it down:

Imagine you have 10 toffees, like the one shown in the image below.

Composition and Properties of Air

The air around us can also be compared to groups of toffees. Just like the toffees in the image are divided into 3 parts, air is also divided into parts containing different types of gases. The largest part is Nitrogen, the second largest is Oxygen, and the smallest part includes gases like Argon and Carbon Dioxide, along with other things like water vapor, smoke, dust, and germs.

But what are these gases? Let us read more on them.

1. Nitrogen:

Nitrogen is a colorless, odorless gas (no smell) and is the most common gas in the atmosphere.
Nitrogen enters the atmosphere through the nitrogen cycle, involving specific living organisms and environmental processes.
Role in Plant Growth: It is crucial for plant growth as it is used to make fertilizers.
Importance for Humans - Nitrogen is also an essential part of proteins in the human body.

2. Oxygen:

Vital for Life: It is essential for respiration (breathing). It is also a supporter of burning.
Supports Growth: Oxygen helps living beings grow.
Oxygen is also a component of the ozone layer, which protects life on Earth from harmful ultraviolet (UV) radiation from the Sun.

3. Argon:

It is a noble gas, which means it doesn’t react easily and is popularly used in light bulbs and welding.
It is a colorless, tasteless, and odorless gas.

4. Carbon Dioxide:

Carbon Dioxide is a small component of air.
It can trap heat and is hence also called a greenhouse gas.
Plants use carbon dioxide for making food (photosynthesis).

5. Others:

In addition to the above-mentioned gases, air also consists of water vapor, smoke, dust particles, and germs.

Test your Understanding:

1. Which gas is a component of ozone layer that helps in blocking harmful ultraviolet rays from the sun?
a) Nitrogen
b) Oxygen
c) Argon
d) Carbon Dioxide

2. Which gas is used by plants for making food?
a) Oxygen
b) Carbon Dioxide
c) Nitrogen
d) Water Vapour

The Properties of Air

Air is all around us, though we can't see it. It is a mixture of gases that takes up space and has weight. Air can move, creating wind; air is flexible - we can compress or expand it and many more. The properties of air are essential for breathing, flying airplanes, and enjoying activities like balloons and bubbles. Let's look into the image to see the different properties of air.

Image of properties of air.

What are the 10 properties of air?

The 10 properties of air are as follows:

Air takes up space: Even though we can’t see it, air fills balloons and our lungs.
Air has weight: It pushes down on us, which we call air pressure.
Air can move: That’s what creates wind.
Air can expand and contract: It grows bigger when heated and shrinks when cooled.
Air can flow: It moves around objects like water does.
Air has oxygen for life: Essential for breathing.
Air is invisible: You can’t see it, but you can feel it.
Air can dissolve in water: That’s how fish breathe underwater.
Air can carry sound: Without air, we couldn’t hear anything!
Air exerts pressure: This helps airplanes fly and keeps objects from collapsing.

Want to know more on properties of air? Check here.

Test your Understanding:

1. Which of the following is a key property of air?
a) Air is visible and has no weight.

b) Air is invisible but has weight.

c) Air does not occupy space.

d) Air cannot exert pressure.

2. Which experiment demonstrates that air occupies space?

a) Filling a balloon.

b) Heating water in a beaker.

c) Melting ice.

d) Boiling salt water.

Facts About Composition and Properties of Air

Although most gases in the air are safe, some can be harmful. Some examples are:

Carbon monoxide: It is a toxic gas emitted from vehicles and burning of substances.
Sulphur dioxide and nitrogen oxides: These gases are emitted from factories, that can cause air pollution.
Air is a mixture of gases, not a single substance, with nitrogen (78%) and oxygen (21%) being its major components.
Air has mass and occupies space, which means it is a form of matter.
Oxygen present in air supports respiration and combustion, making life on Earth possible.
The amount of water vapour in air varies with weather conditions and influences humidity and rainfall.
Air exerts pressure in all directions, known as atmospheric pressure.
Although carbon dioxide is present in small amounts, it is essential for photosynthesis in plants.

Quiz

1. What is the most abundant gas in the Earth's atmosphere?
a) Oxygen
b) Carbon dioxide
c) Nitrogen
d) Argon

2. How do we know that air is present around us?
a) We can see it
b) It is visible in pictures
c) We can feel it
d) We can taste it

3. Air is needed for which of the following processes?
a) Breathing
b) Burning
c) Photosynthesis in plants
d) All of the above

4. What happens when air is cooled?
a) Air becomes lighter and moves upward.
b) Air shrinks.
c) Air disappears.
d) Air expands and becomes denser.

5. Which of the following is NOT found in air?
a) Oxygen
b) Nitrogen
c) Water vapor
d) Gold

Practice Worksheets

Click the button to download the worksheets for hands-on practice!

Orchids' Learning Material

Click the button to download the e-book

Things You Have Learnt!

Air is crucial to support life on Earth. We can live for somedays without food, but we cannot live even for a moment without air.
Air is made up of gases that are important for breathing, protecting us from harmful rays, and helping plants with photosynthesis.
Air has many properties, like - air has oxygen for life, air can move, air can carry sound etc.

Frequently Asked Questions on Composition and Properties of Air

1. How does the composition of air affect the environment?

The Composition and Properties of Air play a vital role in maintaining climate, supporting life, and regulating natural processes. Changes in the balance of gases can contribute to pollution and global warming.

2. Which component of air is very important?

Among the Composition and Properties of Air, oxygen is especially important because it supports respiration and combustion. Nitrogen is also essential for maintaining atmospheric stability.

3. What are the two important composition of air?

The major components in the Composition and Properties of Air are nitrogen (78%) and oxygen (21%). Together, they make up about 99% of the Earth's atmosphere.

4. How does air composition affect breathing?

The Composition and Properties of Air directly influence breathing because oxygen is necessary for the body to produce energy. Poor air quality can make breathing difficult and affect overall health.

5. How many litres of air do we breathe?

An average person breathes about 11,000 litres of air each day. This highlights the importance of understanding the Composition and Properties of Air for maintaining good health.

6. Can poor air quality make you tired?

Yes, poor air quality can reduce the amount of oxygen available and may cause fatigue, headaches, and difficulty concentrating. The Composition and Properties of Air greatly affect our daily well-being.

7. Which country is no. 1 in air pollution?

Air pollution levels change over time and vary from country to country. Understanding the Composition and Properties of Air helps scientists monitor pollution and improve air quality.

8. How to protect from air pollution?

You can protect yourself by avoiding polluted areas, wearing masks when necessary, and increasing indoor ventilation. Maintaining the natural Composition and Properties of Air is important for a healthier environment.

9. What are common symptoms of lack of fresh air?

Lack of fresh air may lead to tiredness, dizziness, headaches, and breathing discomfort. These effects show how the Composition and Properties of Air are closely linked to human health.