Question

How is pressure using to us ? Class 7 science

Answer 1

Answer:

Pressure is useful to us in the form of atmospheric pressure. It is a force exerted on a surface by the air above it as gravity pulls it to Earth. Atmospheric pressure is commonly measured with a barometer.

Answer 2

Very Short Type Questions

Question 1. How does carbon dioxide create green house effect? [V. Imp.]

Answer: Crbon dioxide creates greenhouse effect by trappeing the heat radiated from the earth.

Question 2. What is the significance of greenhouse gas?

Answer: Without the greenhouse gas the earth would have been too cold to line in.

Question 3. What happens when air is heated?

Answer: When air is heated, it expands, becomes lighter and goes up.

Question 4. What is the nature of cold air?

Ans. It has tendency to go down.

Question 5. Why do green plants use carbon dioxide? [Imp.]

Answer: Green plants use carbon dioxide to make their food and release oxygen.

Question 6. What is an important feature of Stratosphere?

Answer: Stratosphere contains a layer of ozone gas.

Question 7. How is ozone important for us? [Imp.]

Answer: It protects us from the harmful effect of the sunrays.

Question 8. What is temperature?

Answer: The degree of hotness and coldness of the air is known as temperature.

Question 9. What is insolation?

Answer: Insolation is the incoming solar energy intercepted by the earth.

Question 10. Why is there no air pressure on the moon?

Answer: There is no air on the moon and therefore no air pressure.

Question 11. Where is air pressure highest?

Answer: Air pressure is highest at the sea level.

Question 12. How does air move?

Answer: Air moves from high pressure areas to low pressure areas.

Question 13. Name three types of winds.

Answer:

Permanent winds

Seasonal winds

Local winds.

Question 14. What is the hot and dry wind of northern planes of India called?

Ans. It is called loo.

Q.15 What is called humidity? [V. Imp.]

Ans. Moisture in the air at any time is called humidity

Q 16 Why do we feel uncomfortable on a humid day?

Ans. It is because sweat from our body does not evaporate easily.

Q.17 How is the flooding of low lying areas caused? [V. Imp.]

Ans. When trees on hill sides are cut, rainwater flows down the bare mountains. This causes flooding of low lying areas.

Q.18 Name various forms of precipitation.

Ans.Rain

Snow

Sleet

Hail

Q.19 How is a wind named?

Ans. A wind is named after the direction from which it blow.