Class 1 Science Chapter 11 Case Based Questions - Air around Us

Case 1: Air Composition

A student is studying the composition of air and its constituents. They want to test their knowledge about the main components of air.

Q1: What are the two primary gases that make up the majority of Earth's atmosphere?
(a) Oxygen and carbon dioxide
(b) Nitrogen and helium
(c) Oxygen and nitrogen
(d) Carbon dioxide and argon
Ans: (c)

Q2: Why is oxygen essential for human and animal respiration?
(a) It helps in photosynthesis
(b) It's needed for burning fires
(c) It supports the water cycle
(d) It's required for the respiration process
Ans: (d)

Q3: What is the main constituent of air that helps in the process of respiration?
(a) Water Vapour
(b) Oxygen
(c) Nitrogen
(d) Carbon Dioxide
Ans: (b)

Q4: What is the approximate percentage of oxygen in dry air?
(a) 4%
(b) 21%
(c) 78%
(d) 0.04%
Ans: (b)

Case 2: Air Pollution

A group of students is discussing the harmful effects of air pollution and its sources.

Q5: How does the presence of carbon dioxide in the air relate to activities like burning fires?
(a) Fire consumes oxygen and releases carbon dioxide.
(b) Fire consumes carbon dioxide and releases oxygen.
(c) Fire consumes nitrogen and releases oxygen.
(d) Fire consumes oxygen and releases nitrogen.
Ans: (a)

Q6: Why do industries use tall chimneys to release smoke, and what is the consequence of this practice on air quality?
Ans: Industries use tall chimneys to disperse harmful emissions, but this contributes to air pollution by releasing pollutants into the atmosphere.

Q7: Which component of air is a byproduct of respiration by humans and animals?
(a) Water Vapour
(b) Oxygen
(c) Nitrogen
(d) Carbon Dioxide
Ans: (d)

Q8: What is the harmful component added to the air when fire burns?
(a) Oxygen
(b) Nitrogen
(c) Carbon Dioxide
(d) Smoke particles
Ans: (d)

Case 3: Importance of Air

A teacher is explaining the various uses of air in our daily lives.

Q9: How does the wind play a role in generating electricity through windmills?
Ans: Wind turns the blades of windmills, which generate mechanical energy that can be converted into electricity.

Q10: Why is air crucial for the flight of insects, birds, and the operation of aeroplanes?
Ans: Air provides the necessary lift and support for flight, enabling insects, birds, and airplanes to stay aloft.

Q11: What is the primary use of windmills?
(a) Drawing water from tube wells
(b) Running flour mills
(c) Producing electricity
(d) All of the above
Ans: (d)

Q12: What role does air play in the distribution of pollen and seeds from flowers?
(a) It helps in seed germination
(b) It aids in plant growth
(c) It carries pollen and seeds to different locations
(d) It promotes photosynthesis in plants
Ans: (c)

Case 4: Oxygen in Water and Soil

A curious student wants to understand how animals living underwater and underground can breathe.

Q13: Explain how animals living underwater are able to respire, and what happens when water is heated.
Ans: Animals living underwater respire by extracting dissolved oxygen in water. When water is heated, air molecules escape from it, creating bubbles.

Q14: How do animals living in soil utilize the air present in it for respiration, and what happens to these pathways during heavy rainfall?
Ans: Animals in soil use air pockets for respiration. Heavy rainfall can block these air pathways, forcing animals to come to the surface for air.

Q15: What happens to air molecules in water when it is heated?
(a) They condense into droplets of water
(b) They escape from the water
(c) They become denser
(d) They turn into ice crystals
Ans: (b)

Q16: Why do earthworms come out of the soil during heavy rainfall?
(a) To escape predators
(b) To find food
(c) To seek moisture and air
(d) To lay eggs in the rain
Ans: (c)

Case 5: Oxygen Balance in the Environment

A student is curious about the role of plants in maintaining the balance of oxygen in the environment.

Q17: Explain how plants contribute to the oxygen balance in the environment through photosynthesis.
Ans: Plants produce oxygen through photosynthesis, where they use sunlight to convert carbon dioxide and water into oxygen and glucose.

Q18: Describe why the balance of oxygen in the environment is essential for the survival of humans and animals.
Ans: The balance of oxygen is crucial because it supports respiration, the process by which humans and animals obtain the energy they need to survive.

Q19: How is the balance of oxygen in the environment maintained?
(a) Through the respiratory processes of animals
(b) Through the combustion of fossil fuels
(c) Through the decomposition of organic matter
(d) Through the photosynthesis of plants
Ans: (d)

Q20: Which process helps plants produce oxygen?
(a) Respiration
(b) Photosynthesis
(c) Decomposition
(d) Combustion
Ans: (b)