CBSE – 7th Standard Science

Free

Question Bank – Chapter 8 – Winds, Storms and Cyclones

CHAPTER 8 

Winds, Storms and Cyclones

 

Q1. What is wind?

Ans. The moving air is called wind. Air moves  the region where the air pressure is high to the region where the pressure is low. The greater the difference in pressure, the faster the air moves.

 

 

Q2. What happens when air gets heated?

Ans. Air around us exerts pressure. Air expands on heating and contracts on cooling.

 Warm air rises up, whereas comparatively cooler air tends to sink towards the earth’s surface. As warm air rises, air pressure at that place is reduced and the cooler air moves to that place.

 

Q3. What causes the wind movement on Earth?

Ans. Uneven heating on the earth is the main cause of wind movements .Sun rays on the earth surface rises the temperature of land and water also, as warm air rises, air pressure at that place is reduced and the cooler air moves to that place but and wind movement begins.

 

Q4. What changes occur during summer due to changes in the temperature of air?

Ans. In summer, near the equator the land warms up faster and most of the time the temperature of the land is higher than that of water in the oceans. The air over the land gets heated and rises.This causes the winds to flow from the oceans towards the land. These are  monsoon winds it carry water and  rains.

 

Q5. Explain why holes are made in hanging banners and hoardings.

Ans. The air exerts pressure it is due to this pressure banners, or flags flutter when the wind is blowing but when the speed of wind increases it will damage the banners thus holes are made in hoardings to give passage to wind .

 

Q6. What are thunderstorms?

Ans. Thunderstorms develop in hot, humid tropical areas as the rising temperatures produce strong upward rising winds, these winds carry water droplets upwards, where they freeze, and fall down again. The swift movement of the falling water droplets along with the rising air creates lightning and sound is called thunderstorm.

 

Q7. What is a cyclone?

Ans. High-speed winds and air pressure difference can cause cyclones. The air tends to rise and causes a drop in pressure. More air rushes to the centre of the storm.  This cycle is repeated. The chain of events ends with the formation of a very low-pressure system with very high-speed winds revolving around it. It is a cyclone.

 

Q8. How does a thunderstorm changes into a cyclone?

Ans. Factors like wind speed, wind direction, temperature and humidity contribute to the development of cyclones. Cyclones can be very destructive. Strong winds push water towards the shore even if the storm is hundreds of kilometres away.

 

Q9. How do we measure wind speed? Is it important?

Ans. Wind speed plays an important role in the formation of storms. It is, therefore, important to measure the wind speed. The instrument that measures the wind speed is called an anemometer.

 

Q10. . If a storm is accompanied by lightning, what precautions should be taken?

Ans. If a storm is accompanied by lightning, we must take the following precautions:

We should not take shelter under an isolated tree, in a forest take shelter under a small tree. Do not lie on the ground.  should not take shelter under an umbrella with a metallic end. If going in car or a bus it is a safe place to take shelter inside

 

Q11 What planning is required in advance to deal with the situation created

by a cyclone?

Ans. It has become easier to monitor cyclones with the help of advance technology like satellites and radars so we should not ignore the warnings issued by the meteorological department through TV, radio, or newspapers. We should make necessary arrangements to shift the essential household goods, domestic animals and vehicles, etc. to safer places.

 

Q12. What is cyclone and what are its different names?

Ans. High-speed winds and air pressure difference can cause cyclones A cyclone is known by different names in different parts of the world. It is called a ‘hurricane’ in the American continent. In Philippines and Japan it is called a ‘typhoon’

 

Q13. What kind of damages is seen after cyclone is formed?

Ans. The low pressure in the eye lifts water surface in the centre. The rising water may be as high as 3–12 metres the seawater enters the low-lying coastal areas, causing severe loss of life and property. It also reduces the fertility of the soil. High-speed winds accompanying a cyclone can damage houses, telephones and other communication systems, trees causing tremendous loss of life and property.

 

Q14. What should be done when a cyclone approaches?

Ans. If cyclone has reached Self-help is the best help. Therefore it is better to plan in advance and be ready with defense against any approaching cyclone Avoid driving on roads through standing water, take shelter in strong places and try to protect head.

 

 

 

Course Curriculum

Post a comment

Your email address will not be published. Required fields are marked *