CBSE Class 6 Science Chapter 15: Air Around Us NCERT Solutions

NCERT Solutions PDF Class 6 PDF

This chapter, 'Air Around Us,' for CBSE Class 6 Science, delves into the fundamental nature of air. The NCERT Solutions provide clear explanations and answers to key questions about the composition of air, including its essential components like nitrogen, oxygen, and carbon dioxide. Students will understand the role of oxygen in respiration and carbon dioxide in photosynthesis. The solutions also demonstrate how air supports burning and is dissolved in water, explaining phenomena like a shrinking cotton wool lump. Furthermore, the chapter highlights the vital interdependence between plants and animals in the exchange of atmospheric gases and lists various activities made possible by air, such as wind power and flight. These solutions are designed to help students grasp these concepts thoroughly and prepare effectively for their exams by offering detailed, step-by-step explanations.

Quick info

BoardCBSE
ClassClass 6
SubjectScience
Session2026
LanguageEnglish
TypeNCERT Solutions
ChapterChapter 15

Chapter summary

Chapter 15, 'Air Around Us,' for Class 6 Science, focuses on the properties and importance of air. The NCERT Solutions cover the composition of air, identifying key gases like nitrogen and oxygen, and explaining their percentages. It addresses the critical role of oxygen for respiration and carbon dioxide for plant photosynthesis. The solutions also explain how to demonstrate that air supports burning and is dissolved in water, and why cotton wool shrinks in water. Finally, it details the reciprocal exchange of gases between plants and animals and lists activities facilitated by air.

Learning outcomes

  • Understand the composition of air and its major components.
  • Identify the gases essential for respiration and photosynthesis.
  • Explain the role of air in supporting combustion.
  • Demonstrate that air is dissolved in water.
  • Describe how plants and animals exchange gases.
  • List various activities made possible by the presence of air.

Topics covered

Paper topics

  • Composition of Air
  • Nitrogen in Air
  • Oxygen in Air
  • Carbon Dioxide in Air
  • Water Vapour and Dust Particles
  • Respiration
  • Photosynthesis
  • Air Supports Burning
  • Air Dissolved in Water
  • Shrinking of Cotton Wool
  • Atmosphere
  • Exchange of Gases

Important topics

  • Composition of Air
  • Oxygen for Respiration
  • Carbon Dioxide for Photosynthesis
  • Air Supports Burning
  • Gas Exchange between Plants and Animals
  • Uses of Air

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Questions and Solutions

Question 1

What is the composition of air?
Solution: Air is a mixture of several gases, along with some water vapour and dust particles. The primary components of air are nitrogen and oxygen, which together constitute approximately 99% of its volume. Nitrogen makes up about 78%, and oxygen about 21%. The remaining 1% is composed of small amounts of other gases like carbon dioxide, argon, and trace amounts of others, as well as variable amounts of water vapour and suspended dust particles.

Question 2

Which gas in the atmosphere is essential for respiration?
Solution: The gas in the atmosphere that is absolutely essential for respiration, the process by which living organisms obtain energy, is oxygen.

Question 3

How will you prove that air supports burning?
Solution: To demonstrate that air supports burning, you can conduct the following experiment:
  1. Place a burning candle upright in a tray filled with a small amount of water.
  2. Carefully cover the burning candle with a glass jar, ensuring the rim of the jar is submerged in the water. This creates an airtight seal.
  3. Observe the candle flame. Initially, it will burn steadily as it consumes the oxygen inside the jar.
  4. As the oxygen inside the jar is used up and converted into carbon dioxide, the flame will start to flicker and eventually go out.
This happens because the burning process requires oxygen, and once the available oxygen is depleted, the flame cannot be sustained. The water level inside the jar will also rise slightly, indicating the consumption of a gas (oxygen) from the air.

Question 4

How will you show that air is dissolved in water?
Solution: You can show that air is dissolved in water by performing this simple experiment:
  1. Take some water in a clean glass vessel or beaker.
  2. Gently heat the water over a tripod stand. Do not let it boil vigorously.
  3. Observe the inner surface of the vessel carefully as the water heats up.
Before the water reaches its boiling point, you will notice small bubbles starting to form and rise from the bottom and sides of the vessel towards the surface. These bubbles are not steam; they are air that was dissolved in the water, which becomes less soluble as the temperature increases and escapes from the water.

Question 5

Why does a lump of cotton wool shrink in water?
Solution: A lump of cotton wool contains a significant amount of trapped air within its fibres. When the cotton wool is dipped into water, the water penetrates the fibres and replaces the air. Since water is much denser and occupies less volume than the air it displaces within the cotton's structure, the cotton wool appears to shrink.

Question 6

The layer of air around the earth is known as ______.
Solution: The layer of air that surrounds the Earth is known as the atmosphere.

Question 7

The component of air used by green plants to make their food, is ______.
Solution: The component of air that green plants utilize during photosynthesis to produce their food is carbon dioxide.

Question 8

List five activities that are possible due to the presence of air.
Solution: The presence of air makes numerous activities possible. Here are five examples:
  1. Respiration: All living beings depend on oxygen from the air for respiration to survive.
  2. Photosynthesis: Green plants use carbon dioxide from the air to produce their food.
  3. Power Generation: Wind, which is moving air, is used to generate electricity using windmills.
  4. Burning: Air, specifically oxygen, is necessary for the combustion of fuels and other substances.
  5. Transportation and Movement: Air provides the medium for the movement of sailing yachts, gliders, parachutes, and aeroplanes. It also aids in the scattering of seeds and pollen.

Question 9

How do plants and animals help each other in the exchange of gases in the atmosphere?
Solution: Plants and animals are interdependent in the exchange of atmospheric gases, creating a vital cycle for life on Earth:
  • Respiration: Both plants and animals respire. During respiration, they take in oxygen from the atmosphere and release carbon dioxide as a byproduct.
  • Photosynthesis: Green plants, in the presence of sunlight, use the carbon dioxide released by animals (and other sources) to perform photosynthesis. In this process, they produce their food (glucose) and release oxygen back into the atmosphere.
This continuous exchange ensures that there is a balance of oxygen and carbon dioxide in the atmosphere, supporting the life of both plants and animals.

Common mistakes

  • Confusing the percentages of gases in air.
  • Not clearly explaining the interdependence of plants and animals for gas exchange.
  • Failing to provide sufficient detail in experimental explanations.
  • Overlooking the role of dissolved air in water.

Revision tips

  • Memorize the approximate percentages of nitrogen and oxygen in the air.
  • Clearly understand the gas exchange cycle between plants and animals.
  • Review the experiments described to prove air's properties (supports burning, dissolved in water).
  • List and remember the various uses of air in daily life and technology.

Practice MCQs

Q1. What are the two main gases that make up approximately 99% of the air?

Q2. Which gas is essential for respiration by living beings?

Q3. What gas do green plants use from the atmosphere to make their food?

Q4. What phenomenon proves that air supports burning?

Q5. What indicates that air is dissolved in water when water is heated?

Frequently asked questions

What is the main composition of air according to NCERT Class 6 Science?

Air is mainly composed of nitrogen and oxygen, which together make up about 99% of it. The remaining 1% consists of carbon dioxide, other gases, water vapour, and dust particles.

Which gas is crucial for breathing?

Oxygen is the essential gas in the atmosphere that living beings use for respiration.

How does this chapter explain that air supports burning?

The chapter explains that air supports burning by showing that a flame goes out when the supply of air (oxygen) is cut off, for example, by covering a burning candle with a jar.

Can air be found in water?

Yes, air is dissolved in water. This can be observed when water is heated, and bubbles of air start to rise from it.

What is the relationship between plants and animals regarding air?

Plants and animals have a symbiotic relationship concerning gases. Animals take in oxygen and release carbon dioxide, while plants take in carbon dioxide for photosynthesis and release oxygen.

What does the term 'atmosphere' refer to in this chapter?

The atmosphere is defined as the layer of air that surrounds the Earth.

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