15. AIR AROUND US
Important Questions with solution:
Question1: What is air ?
Answer: Air is a mixture of various gases like nitrogen, oxygen, carbon dioxide and some other gases and smoke and dust particles.
Question2: What is atmosphere?
Answer: Our earth is surrounded by a thin layer of air. This layer extends up to
many kilometres above the surface of the earth and is called atmosphere.
Question3: Whch gas is carried by mountaineers while climbing up?
Answer: Mountaineers carry oxygen gas in cylinders while climbing up.
Question4: What is wind?
Answer: Moving air is called wind.
Question5: Why does Firki rotate?
Answer: When the fast-moving air exerts pressure on Firki, it rorates very fast.
Question6: What is reason that when the air comes in the contact of cold surfaces, the drops of water become visible on the surfaces?
Answer: When the air comes in the contact of cold surface, the water vapour present in air condensed and become water drops.
Question7: Which gas support burning?
Answer: Oxygen.
Question8: Which gas does not support burning?
Answer: Nitrogen.
Question9: In the presence of which gas do we feel suffocated?
Answer: Carbon dioxide.
Question10: Which gas is released on burning an object?
Answer: Carbon dioxide.
Question11: Which gas is used by plants and animals during respiration?
Answer: Oxygen.
Question12: Which gas is released by plants and animals during respiration?
Answer: Carbon dioxide.
Question13: Which gas is used by green plants during the process of photosynthesis?
Answer: Carbon dioxide.
Question14: Which gas is released by green during food making process as product?
Answer: Oxygen.
Question15: Which gas is present in atmosphere in large amount?
Answer: Nitrogen 79%.
Question16: Why are long fireplaces (Chimaneys) installed in factories?
Answer: Smokes have some gases and very tiny dust particles which are usually harmful. This is the reason to install long fireplaces (Chimaneys) in factory as they take the harmful smoke and gases away from our noses.
Question17: What are the role of fine hair and mucus present inside our nose?
Answer: When we inhale air during breathing through our nostrils. Fine hair and mucus are present inside the nose to prevent dust particles from getting into the respiratory system.
Question18: How animals and plants are interdependence on each other?
Answer: Animals and plants are interdependence on each other, because these organisms live on gaseous exchanges like oxygen and carbon dioxide. They would consume all the carbon dioxide in the atmosphere. We can see that both need each other, as the balance of oxygen and carbon dioxide in the atmosphere is thus maintained. This shows the interdependence of plants and animals.
Question19: Write the some properties of air?
Answer:
Properties of air:
(i) Air occupies space.
(ii) Air has no colour and one can see through it.
(iii) It is transparent.
(iv) It fills the space.
(v) Air apply force and has power to do work.
Question20. What is windmill?
Answer: The windmill is used to draw water from tubewells and to run flour
mills. Windmills are also used to generate electricity.