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Air Around Us - Importance of Air for Living Beings

Grade 6CBSE

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

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Air is a mixture of several gases, mainly Nitrogen (N2≈78%N_2 \approx 78\%) and Oxygen (O2≈21%O_2 \approx 21\%). Other components include Carbon dioxide (CO2CO_2), water vapor (H2OH_2O), and dust particles.

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Respiration is essential for all living beings. During this process, organisms take in Oxygen (O2O_2) from the air and release Carbon dioxide (CO2CO_2) and energy.

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Photosynthesis is the process by which green plants make their own food. They consume Carbon dioxide (CO2CO_2) and water (H2OH_2O) in the presence of sunlight and chlorophyll to produce glucose (C6H12O6C_6H_{12}O_6) and release Oxygen (O2O_2).

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The balance of Oxygen (O2O_2) and Carbon dioxide (CO2CO_2) in the atmosphere is maintained through the processes of photosynthesis by plants and respiration by both plants and animals.

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Aquatic animals like fish use the dissolved Oxygen (O2O_2) present in water for breathing through specialized organs like gills.

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Soil contains air trapped in the spaces between soil particles. Organisms living in the soil, such as earthworms and plant roots, use this air for respiration.

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Wind is moving air. It helps in the dispersal of seeds and pollen grains, and it is also used to generate electricity through windmills.

📐Formulae

Photosynthesis: 6CO2+6H2O→Sunlight/ChlorophyllC6H12O6+6O2\text{Photosynthesis: } 6CO_2 + 6H_2O \xrightarrow{\text{Sunlight/Chlorophyll}} C_6H_{12}O_6 + 6O_2

Respiration: C6H12O6+6O2→6CO2+6H2O+Energy\text{Respiration: } C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + \text{Energy}

💡Examples

Problem 1:

Why do earthworms come out of the soil during heavy rains?

Solution:

During heavy rains, water fills the tiny air spaces between soil particles where air is usually present. Since the earthworms cannot get the Oxygen (O2O_2) they need for respiration underwater, they are forced to come out to the surface to breathe.

Explanation:

Soil organisms depend on the air trapped in soil pores. Displacement of this air by H2OH_2O causes them to seek air above ground.

Problem 2:

Explain why a candle stops burning when covered with an inverted glass jar.

Solution:

Burning (combustion) requires a continuous supply of Oxygen (O2O_2). When the jar is inverted over the candle, the supply of fresh air is cut off. The candle continues to burn only as long as the O2O_2 inside the jar lasts. Once the O2O_2 is consumed and replaced by CO2CO_2, the flame goes out.

Explanation:

This demonstrates that air (specifically O2O_2) is a supporter of combustion.

Problem 3:

How is the balance of O2O_2 and CO2CO_2 maintained in nature?

Solution:

Animals and plants perform respiration, which consumes O2O_2 and produces CO2CO_2. However, green plants also perform photosynthesis, which consumes CO2CO_2 and produces O2O_2. Since plants produce more O2O_2 during the day than they consume during respiration, there is a net release of O2O_2, maintaining the atmospheric balance.

Explanation:

The interdependence of plants and animals ensures the stability of gas concentrations in the atmosphere.