Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
Air is a mixture of several gases, mainly Nitrogen () and Oxygen (). Other components include Carbon dioxide (), water vapor (), and dust particles.
Respiration is essential for all living beings. During this process, organisms take in Oxygen () from the air and release Carbon dioxide () and energy.
Photosynthesis is the process by which green plants make their own food. They consume Carbon dioxide () and water () in the presence of sunlight and chlorophyll to produce glucose () and release Oxygen ().
The balance of Oxygen () and Carbon dioxide () in the atmosphere is maintained through the processes of photosynthesis by plants and respiration by both plants and animals.
Aquatic animals like fish use the dissolved Oxygen () present in water for breathing through specialized organs like gills.
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.
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
💡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 () 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 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 (). 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 inside the jar lasts. Once the is consumed and replaced by , the flame goes out.
Explanation:
This demonstrates that air (specifically ) is a supporter of combustion.
Problem 3:
How is the balance of and maintained in nature?
Solution:
Animals and plants perform respiration, which consumes and produces . However, green plants also perform photosynthesis, which consumes and produces . Since plants produce more during the day than they consume during respiration, there is a net release of , maintaining the atmospheric balance.
Explanation:
The interdependence of plants and animals ensures the stability of gas concentrations in the atmosphere.