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NCERT Class 6 Science Chapter 11 notes explain different aspects of air. We have tried to explain all the facts and concepts with some pictures, which help you view significant phenomena around us. In addition, we have used simple language to define important terms like atmosphere, cloud, wind, etc. Furthermore, you also get solutions to all answers for questions in the Exercise to help you with your homework and tests. Additionally, you can also download PDFs to get a printout of all questions and answers to expand your knowledge and ace your tests.
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Summary of NCERT Class 6 Science Chapter 11
Class 6 Science Chapter 11 is a window to the air around us. In this chapter, we get to learn about the properties, components, and composition of air. Also, we learn about the symbiotic cycle and breathing of different living organisms. Additionally, we get to know about the wind, clouds, atmosphere, respiration, transpiration, and photosynthesis.
Air around Us Class 6 Notes
All the topics mentioned in the summary have been made into notes format precisely to make it easy for you to understand, learn, and revise them. Let us now explore all important concepts in NCERT Class 6 Science Chapter 11!!
Properties of Air
Here are some important properties of air:
- Air cannot be seen but it can be felt.
- Air occupies space
- Air is present all around us
- Air does not have any colour
- Air is transparent
Components of Air
Air is a mixture of water vapour, oxygen, nitrogen, carbon dioxide, and dust and smoke. Here are some key properties of all components of air:
Water Vapour
When air touches a cool surface, it condenses to form water droplets. These droplets were initially in the form of gas in the air. This gaseous substance is called water vapour. This component of air is responsible for the water cycle in nature, which is essential for the life cycle of the Earth.
Oxygen
This gas is essential for the existence of life on Earth. It is responsible for respiration, transpiration, and photosynthesis. All these processes support life on the planet. In addition, oxygen also supports the burning of fossil fuels, candles, etc.
Nitrogen
Nitrogen is the major component of air. It does not support burning. However, it is essential for food production in plans as its presence in soil provides nutrition to fruits and vegetables.
Carbon dioxide
Carbon dioxide is a minor component of air. This gas is used by plants and animals for respiration. Also, carbon dioxide is required for photosynthesis in plants. However, excess carbon dioxide can cause suffocation and global warming.
Dust and Smoke
Smoke is produced due to the burning of fossil fuels. It contains carbon dioxide and other gases as well as dust particles. Both dust and smoke are harmful to living organisms and the environment.
You can also learn about the effect of excess dust and smoke in Essay on Air Pollution for Students
Composition of Air
Air is a mixture of different gases. It contains 78% nitrogen, 215 oxygen, 0.9% argon, 0.04% carbon dioxide, and nearly 1% water vapour. Additionally, the air contains smoke and dust particles.
How is Oxygen Replaced in the Atmosphere?
Oxygen contributes to the 21% of the air present in the atmosphere. All living organisms use this gas for respiration. To balance the composition of oxygen and carbon dioxide in the atmosphere, plants perform photosynthesis. In this biological process, plants inhale carbon dioxide and exhale oxygen. With this process, oxygen is replaced in the atmosphere.
Symbiotic Cycle
Here is a brief overview of the symbiotic relationship between different organisms or the symbiotic cycle:
- Each organism in the environment mutually benefits from each other.
- Plants provide us with oxygen and other goods, and we provide them with more than just carbon dioxide; we also benefit them in other ways.
- It takes the shape of a cycle. Oxygen and carbon dioxide are recycled in the environment through respiration and photosynthesis.
Also Read: What is Botany?
How do Living Organisms Breathe?
Different organisms inhale and exhale air through different processes. Here is how human beings and terrestrial animals, plants, and aquatic animals breathe:
- Human Beings and Terrestrial Animals: These organisms inhale oxygen through the nose and mouth and exhale carbon dioxide through the nose. This process takes place in the lungs of animals and humans.
- Plants: The green leaves of plants breathe for plants. Leaves intake carbon dioxide and produce oxygen as waste products.
- Aquatic Animals: Aquatic animals such as fishes use oxygen dissolved in water to breathe.
Also Read: Breathing And Exchange of Gases – Class 11
Important Definitions in NCERT Class 6 Science Chapter 11
Now, let us learn some definitions included in CBSE Class 6 Science Chapter 11. These definitions are in simple language designed for young minds like you.
Atmosphere
The planet Earth is surrounded by a layer of air. It is a thin layer that extends many kilometres above the Earth’s surface. This layer is known as the atmosphere.
Wind
The wind is the name for moving air. During storms, the wind blows so quickly that it even uproots trees in their path. We can feel the wind as it sways leaves on a tree.
Clouds
These are groups of tiny water droplets held together by the air in the atmosphere. Water vapour from water bodies on the earth evaporates to condense and form clouds above the surface of the Earth.
Respiration
Animals and humans inhale oxygen and exhale oxygen to survive. This process of inhalation and exhalation is known as respiration.
Photosynthesis
Photosynthesis refers to the process by which plants prepare their food with the help of sunlight and carbon dioxide. Green leaves of plants inhale carbon dioxide from the air and exhale oxygen as a waste product in the food production process. This is the process by which plants respire and survive.
You may get more information about photosynthesis from Class 11 Photosynthesis in Higher Plants NCERT, Notes.
Transpiration
Transpiration is the method through which plants lose water. It refers to the mechanism through which plants expel extra water through stomata on the surface of leaves. Water from plant leaves evaporates mostly through transpiration.
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Important Questions and Answers in NCERT Class 6 Science Chapter 11
In this section, our subject experts have provided NCERT solutions to all questions in CBSE Class 6 Science Chapter 11. All the answers are according to the latest curriculum of this education board in India.
Ques 1: What is the composition of air?
Ans: Air is made up of oxygen, water vapour, carbon dioxide, nitrogen, and dust and smoke.
Ques 2: Which gas in the air is important for respiration?
Ans: Oxygen in the air is important for respiration.
Ques 3: How can you prove that air supports burning?
Ans: Put two candles of equal length on a table. Now, light the two candles. After this, cover one lit candle with an inverted glass tumbler. Now, we see that the flame of the covered candle is extinguished after some time. The covered candle gets extinguished because air gets cut when we put a glass tumbler on it as air is required to support burning. Whereas, the open candle continues to burn as it gets a regular air supply.
Ques 4: How will you prove that air is dissolved in water?
Ans: Fill a container with water. On a tripod stand, slowly warm it up. Examine the interior of the container before the water starts to boil. Inside, we see little bubbles. These bubbles are a result of water containing dissolved air. The air that has been dissolved in the water escapes when it is first heated. The results of this experiment indicate that there is air in the water.
Ques 5: Why does a lump of cotton wool shrink in water?
Ans: In water, cotton wool lumps shrink because water replaces the air inside them, causing the layers to adhere to one another.
Ques 6: The layer of air around the Earth is called ______________.
Ans: Atmosphere
Ques 7: The component of air used by green plants for photosynthesis is ____________.
Ans: Carbon dioxide
Ques 8: Name five activities that are possible due to the presence of air.
Ans: Here are the five activities that occur due to air:
- Transpiration
- Respiration
- Photosynthesis
- Winnowing
- Cloud formation
Ques 9: How do plants and animals help each other in the exchange of gases in the atmosphere?
Ans: Animals and plants use oxygen from the air for respiration, which also involves the emission of carbon dioxide gas into the atmosphere. In addition, during the process of photosynthesis, green plants also release oxygen gas by utilising carbon dioxide. Consequently, in this way, the exchange of gases in the atmosphere is aided by the cooperation of plants and animals.
Also Read:
Explore Notes of All subjects of CBSE Class 6:-
| CBSE NCERT Notes Class 6 English | CBSE NCERT Notes Class 6 History | CBSE NCERT Notes Class 6 Geography |
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FAQs
Ans: Photosynthesis refers to the process by which plants prepare their food with the help of sunlight and carbon dioxide.
Ans: The process by which living organisms inhale air and exhale air is called respiration.
Ans: Here are the key properties of air:
-It cannot be seen but it can be felt.
-It occupies space
-It is present all around us
-It does not have any colour
-It is transparent
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