Pressure, Winds, Storms, and Cyclones Class 8 (Curiosity)

Q 1
Question
Choose the correct statement. (i) Vessel R is filled with water; when pouring stops, the water level will be (a) highest in P, (b) highest in Q, (c) highest in R, (d) equal in all three. (ii) Sucker M is pressed on a smooth surface and identical sucker N on a rough surface: (a) both stick, (b) neither sticks, (c) M sticks but N does not, (d) N sticks but M does not. (iii) A roof water tank is at height H; for more pressure on the ground floor, one should (a) increase H, (b) decrease H, (c) use a wider tank, (d) use a smaller tank. (iv) Two vessels A and B have water to the same level; comparing pressure P and force F at the bottom.
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Q 2
Question
State whether the following statements are True [T] or False [F]. (i) Air flows from a region of higher pressure to a region of lower pressure. (ii) Liquids exert pressure only at the bottom of a container. (iii) Weather is stormy at the eye of a cyclone. (iv) During a thunderstorm, it is safer to be in a car.
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Q 3
Question
Fig. 6.23a shows a boy lying horizontally, and Fig. 6.23b shows the boy standing vertically on a loose sand bed. In which case does the boy sink more in the sand? Give reasons.
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Q 4
Question
An elephant stands on four feet. If the area covered by one foot is 0.25 m², calculate the pressure exerted by the elephant on the ground if its weight is 20000 N.
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Q 5
Question
There are two boats, A and B. Boat A has a base area of 7 m² and 5 persons in it. Boat B has a base area of 3.5 m² and 3 persons in it. If each person weighs 700 N, find which boat experiences more pressure on its base, and by how much.
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Q 6
Question
Would lightning occur if air and clouds were good conductors of electricity? Give reasons for your answer.
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Q 7
Question
What will happen to the two identical balloons A and B (Fig. 6.24) when water is filled into the bottle up to a certain height? Will both balloons bulge? If yes, will they bulge equally? Explain your answer.
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Q 8
Question
Explain how a storm becomes a cyclone.
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Q 9
Question
Fig. 6.25 shows trees along the sea coast on a summer afternoon. Identify which side is land — A or B — and explain your answer.
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Q 10
Question
Describe an activity to show that air flows from a region of high pressure to a region of low pressure.
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Q 11
Question
What is a thunderstorm? Explain the process of its formation.
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Q 12
Question
Explain the process that causes lightning.
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Q 13
Question
Explain why holes are made in banners and hoardings.
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Project 1
Project
Hold a strip of paper, 18 cm long and 2 cm wide, between your thumb and forefinger so that it hangs freely. Predict what you will observe if you blow over the paper. Perform the activity now. Note down your observations and interpret your results.
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Key Points
When you blow over the top, the paper strip rises — fast air above it has lower pressure.
Key Points / Good Practices
Predict first — many expect the strip to be pushed down, but it lifts up.
Blow steadily across the top surface of the strip, not underneath it.
The fast-moving air above lowers the pressure there.
The higher pressure below then pushes the strip upward.
This is the same idea as high-speed winds lowering air pressure.
Fast air over the strip lowers the pressure above it, so the strip rises.

Project 2
Project
List three major cyclones which have occurred in India in the last 20 years. List two major destructions caused by each of the cyclones. What measures were taken by the local government and communities to reduce the loss of life and destruction of property? Mention two suggestions you would like to propose to the local government.
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Key Points
Research recent Indian cyclones, their damage, the relief measures, and add your own ideas.
Key Points / Good Practices
Pick three well-documented cyclones (for example, Amphan, Fani, Hudhud).
For each, note two major effects — such as flooding, fallen trees, power cuts or crop loss.
List measures taken: early IMD warnings, evacuation to cyclone shelters, relief kits.
Use reliable sources and present your data in a neat table.
Suggest practical ideas, like stronger shelters or better early-warning sirens.
A short data study of recent cyclones, their damage, the response, and your suggestions.

Project 3
Project
Collect data on the strength of thunderstorms for various regions of India. Compare your findings and identify which regions are more prone to thunderstorms. Can you give reasons for your findings?
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Key Points
Hot, humid regions with plenty of moisture turn out to be the most thunderstorm-prone.
Key Points / Good Practices
Gather thunderstorm data for several states from IMD or reliable websites.
Make a table or bar chart to compare how often and how strongly they occur.
Mark the more prone regions, such as the north-east and eastern India.
Link the pattern to heat and moisture — both are needed for thunderstorms.
Write a short conclusion explaining why those regions are more affected.
Regions with more heat and moisture get more thunderstorms — show it with data.