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Class 8 Science Chapter 6 – Pressure, Winds, Storms, and Cyclones | NCER

Practise Class 8 Science Chapter 6 – Pressure, Winds, Storms, and Cyclones with this easy NCERT Curiosity worksheet. Includes important questions and revision exercises to strengthen understanding of air pressure, winds, storms and cyclones and prepare effectively for class tests and exams.NCERT Curiosity Worksheet

Pressure, Winds, Storms, and Cyclones

Class 8 Science | Chapter 6 Worksheet

Curiosity — Textbook of Science for Grade 8

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Name: ____________________
Class & Section: ____________________
Date: ____________________

Part A — Quick Revision

Pressure: Pressure is the force acting per unit area.
Pressure = Force ÷ Area
SI unit of pressure: pascal (Pa) or N/m².
Important idea: Smaller area produces greater pressure for the same force.
Liquid pressure: Liquids exert pressure on the bottom and sides of containers. Liquid pressure increases with the height of the liquid column.
Atmospheric pressure: The pressure exerted by the air around us.
Wind: Air moves from a region of high pressure to a region of low pressure.
Thunderstorm: A storm accompanied by lightning and thunder.
Cyclone: A large spinning storm that forms mainly over warm ocean waters around a very low-pressure region.

Part B — Fill in the Blanks

1. Pressure is force per unit .
2. The SI unit of pressure is .
3. Air moves from a region of pressure to a region of pressure.
4. The pressure exerted by air around us is called pressure.
5. Warm air is generally and rises upward.
6. The calm central region of a cyclone is called the .
7. A storm accompanied by lightning and thunder is called a .
8. A lightning conductor provides an easy path for electric charges to move into the .

Part C — Multiple Choice Questions

1. Which change will increase pressure when the force remains the same?
(a) Increasing area
(b) Decreasing area
(c) Removing force
(d) Increasing volume
2. Why are broad straps used in school bags?
(a) They increase weight
(b) They decrease area
(c) They reduce pressure on shoulders
(d) They increase pressure
3. Liquid pressure increases when the:
(a) height of liquid column increases
(b) container becomes empty
(c) liquid disappears
(d) pressure becomes zero
4. Which instrument is used to monitor weather and cyclones in India?
(a) ISRO only
(b) India Meteorological Department
(c) Railway Department
(d) Forest Department
5. A cyclone generally forms over:
(a) cold deserts
(b) warm ocean waters
(c) dry mountains
(d) frozen lakes
6. Which statement about the eye of a cyclone is correct?
(a) It has the strongest winds
(b) It is the region of lowest pressure and is relatively calm
(c) It is always dry
(d) It is outside the cyclone
7. Lightning is produced by:
(a) movement of soil
(b) sudden flow of electric charges
(c) evaporation only
(d) falling leaves
8. What happens when air moves between two balloons?
(a) Pressure between them increases
(b) Pressure between them decreases and the balloons move towards each other
(c) The balloons disappear
(d) Nothing happens

Part D — True or False

1. Pressure is force per unit area. ________
2. Liquids exert pressure only at the bottom of a container. ________
3. Air flows from high pressure to low pressure. ________
4. Warm air rises and can create a low-pressure region. ________
5. The eye of a cyclone has the strongest winds. ________
6. Lightning can occur between clouds and the ground. ________
7. A lightning conductor helps protect buildings. ________
8. Cyclones become stronger after moving far over land because they continue receiving warm ocean moisture. ________

Part E — Short Answer Questions

1. Why are broad straps more comfortable than narrow straps?

Answer: ________________________________________________

2. Why is a knife with a sharp edge easier to use?

Answer: ________________________________________________

3. Why are overhead water tanks placed at a height?

Answer: ________________________________________________

4. Do liquids exert pressure on the sides of a container?

Answer: ________________________________________________

5. What is atmospheric pressure?

Answer: ________________________________________________

6. Why does air escape from an inflated balloon when its mouth is opened?

Answer: ________________________________________________

7. Why do two balloons move towards each other when air is blown between them?

Answer: ________________________________________________

8. Why can strong winds blow off roofs?

Answer: ________________________________________________

9. What is a thunderstorm?

Answer: ________________________________________________

10. What is the eye of a cyclone?

Answer: ________________________________________________

Part F — Numerical Questions

1. A force of 100 N acts on an area of 2 m². Calculate the pressure.

Working: ________________________________________________

Answer: ________________________________________________

2. An elephant stands on four feet. If the area covered by one foot is 0.25 m² and its weight is 20000 N, calculate the pressure exerted by the elephant on the ground.

Working: ________________________________________________

Answer: ________________________________________________

3. A force of 500 N acts on an area of 5 m². Find the pressure.

Working: ________________________________________________

Answer: ________________________________________________

4. A force of 200 N acts on an area of 4 m². Find the pressure.

Working: ________________________________________________

Answer: ________________________________________________

Part G — Application-Based Questions

1. A student carries the same school bag using narrow straps and then broad straps. In which case will the shoulders feel less pressure? Why?

Answer: ________________________________________________

2. Water comes out more strongly from a tap connected to a tank placed higher above the ground. Explain why.

Answer: ________________________________________________

3. A strong wind is blowing over the roof of a house. Explain why opening doors and windows can sometimes help protect the roof.

Answer: ________________________________________________

4. Why does sea breeze occur during the day?

Answer: ________________________________________________

5. Why does land breeze occur at night?

Answer: ________________________________________________

6. Why should we avoid standing under tall trees during lightning?

Answer: ________________________________________________

7. Why is a car or bus comparatively safer during lightning?

Answer: ________________________________________________

Part H — Higher Order Thinking

1. Why does a dam have a broader base than its top?

Answer: ________________________________________________

2. Why does a cyclone gradually lose strength after moving over land?

Answer: ________________________________________________

3. Why are holes made in banners and hoardings?

Answer: ________________________________________________

4. What would happen to winds if there were no differences in air pressure?

Answer: ________________________________________________

5. Why is the eye of a cyclone relatively calm even though the surrounding region has strong winds?

Answer: ________________________________________________

Part I — Book Questions: Keep the Curiosity Alive

1. Choose the correct statement.

(i) Look at Fig. 6.21 carefully. Vessel R is filled with water. When pouring of water is stopped, the level of water will be ____________________.

(a) the highest in vessel P
(b) the highest in vessel Q
(c) the highest in vessel R
(d) equal in all three vessels

(ii) A rubber sucker (M) is pressed on a flat smooth surface and an identical sucker (N) is pressed on a rough surface:

(a) Both M and N will stick to their surfaces.
(b) Both M and N will not stick to their surfaces.
(c) M will stick but N will not stick.
(d) M will not stick but N will stick.

(iii) A water tank is placed on the roof of a building at a height ‘H’. To get water with more pressure on the ground floor, one has to

(a) increase the height ‘H’ at which the tank is placed.
(b) decrease the height ‘H’ at which the tank is placed.
(c) replace the tank with another tank of the same height that can hold more water.
(d) replace the tank with another tank of the same height that can hold less water.

(iv) Two vessels, A and B contain water up to the same level as shown in Fig. 6.22. PA and PB is the pressure at the bottom of the vessels. FA and FB is the force exerted by the water at the bottom of the vessels A and B.

(a) PA = PB, FA = FB
(b) PA = PB, FA <FB
(c) PA < PB, FA = FB
(d) PA > PB, FA > FB

2. 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. [ ]

3. Fig. 6.23 a 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 sand? Give reasons.

Answer: ________________________________________________

4. 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.

Answer: ________________________________________________

5. There are two boats, A and B. Boat A has a base area of 7 m2 , and 5 persons are seated in it. Boat B has a base area of 3.5 m2 , and 3 persons are seating in it. If each person has a weight of 700 N, find out which boat will experience more pressure on its base and by how much?

Answer: ________________________________________________

6. Would lightning occur if air and clouds were good conductors of electricity? Give reasons for your answer.

Answer: ________________________________________________

7. What will happen to the two identical balloons A and B as shown in Fig. 6.24 when water is filled into the bottle up to a certain height. Will both the balloons bulge? If yes, will they bulge equally? Explain your answer.

Answer: ________________________________________________

8. Explain how a storm becomes a cyclone.

Answer: ________________________________________________

9. Fig. 6.25 shows trees along the sea coast in a summer afternoon. Identify which side is land— A or B. Explain your answer.

Answer: ________________________________________________

10. Describe an activity to show that air flows from a region of high pressure to a region of low pressure.

Answer: ________________________________________________

11. What is a thunderstorm? Explain the process of its formation.

Answer: ________________________________________________

12. Explain the process that causes lightning.

Answer: ________________________________________________

13. Explain why holes are made in banners and hoardings.

Answer: ________________________________________________

Answer Key — Easy Answers

Part B — Fill in the Blanks

1. area
2. pascal (Pa)
3. high, low
4. atmospheric
5. light
6. eye
7. thunderstorm
8. ground

Part C — MCQs

1. (b)
2. (c)
3. (a)
4. (b)
5. (b)
6. (b)
7. (b)
8. (b)

Part D — True or False

1. True
2. False
3. True
4. True
5. False
6. True
7. True
8. False

Part E — Short Answers

1. Broad straps spread the force over a larger area, so they produce less pressure on the shoulders.
2. A sharp edge has a smaller area, so it produces greater pressure and cuts easily.
3. A higher tank produces greater water pressure and gives a stronger stream of water.
4. Yes. Liquids exert pressure on the bottom and sides of a container.
5. Atmospheric pressure is the pressure exerted by the air around us.
6. Air moves from the higher pressure inside the balloon to the lower pressure outside.
7. Fast-moving air creates lower pressure between the balloons. Higher pressure outside pushes them together.
8. High-speed wind creates lower pressure above the roof. The pressure difference can push the roof upward.
9. A thunderstorm is a storm with lightning and thunder, usually with strong winds and rain.
10. The eye is the calm central region of a cyclone where the pressure is lowest.

Part F — Numerical Answers

1. Pressure = Force ÷ Area = 100 ÷ 2 = 50 N/m².
2. Total area = 4 × 0.25 = 1 m².
Pressure = 20000 ÷ 1 = 20000 N/m².
3. Pressure = 500 ÷ 5 = 100 N/m².
4. Pressure = 200 ÷ 4 = 50 N/m².

Part G — Application Answers

1. Broad straps. They spread the force over a larger area and reduce pressure.
2. Pressure of a liquid increases with the height of its column. A higher tank gives greater pressure.
3. Opening doors and windows reduces the pressure difference between inside the house and above the roof.
4. During the day, land heats faster. Warm air rises over land, creating low pressure. Air moves from the sea towards land.
5. At night, land cools faster. The sea remains warmer, so air rises over the sea and air moves from land towards sea.
6. Tall trees can attract lightning, so it is safer to stay away from them.
7. A car or bus provides comparatively better protection from lightning.

Part H — HOTS Answers

1. Water pressure is greater near the bottom, so a dam needs a broad and strong base.
2. Over land, the cyclone loses its supply of warm, moist air from the ocean.
3. Holes allow air to pass through and reduce the force of strong winds on the banner or hoarding.
4. Without pressure differences, there would be no driving force for air to move from one region to another.
5. The eye has the lowest pressure and relatively calm air, while the surrounding region has very strong winds.

Book Questions — Answers

1(i). (d) equal in all three vessels.
1(ii). (a) Both M and N will stick to their surfaces.
1(iii). (a) increase the height ‘H’ at which the tank is placed.
1(iv). (b) PA = PB, FA < FB.
2.
(i) True
(ii) False
(iii) False
(iv) True
3. The boy standing vertically sinks more because his weight acts over a smaller area, producing greater pressure on the sand.
4. Total area = 4 × 0.25 = 1 m².
Pressure = 20000 ÷ 1 = 20000 N/m².
5. Boat A: Total weight = 5 × 700 = 3500 N.
Pressure = 3500 ÷ 7 = 500 N/m².

Boat B: Total weight = 3 × 700 = 2100 N.
Pressure = 2100 ÷ 3.5 = 600 N/m².

Therefore, Boat B experiences more pressure by 100 N/m².
6. No. If air and clouds were good conductors, charges would flow away gradually instead of building up enough to produce lightning.
7. Both balloons will bulge because water exerts pressure on the walls of the bottle. If they are at the same depth, the pressure on them will be equal.
8. A cyclone forms when warm moist air rises over warm ocean water, creating very low pressure. Surrounding air rushes in and rises. Earth’s rotation makes the air spin, forming a cyclone.
9. Side A is the land side if the trees are bending towards the sea. During the afternoon, land heats faster, so air moves from the sea towards the land.
10. Connect an inflated balloon to an uninflated balloon using a straw. Air moves from the inflated balloon, where pressure is high, to the uninflated balloon, where pressure is low.
11. A thunderstorm is a storm accompanied by lightning and thunder. Warm moist air rises, cools and forms clouds. Strong winds cause charge separation in the clouds, producing lightning and thunder.
12. Strong winds cause water droplets and ice particles to rub and develop electric charges. When opposite charges suddenly flow, a bright flash called lightning is produced.
13. Holes allow air to pass through the banner or hoarding. This reduces the force of strong winds and helps prevent it from being blown away.

Challenge Corner

1. If the force on an object is doubled while its area remains the same, what happens to pressure?
2. If the area is doubled while the force remains the same, what happens to pressure?
3. Why does wind become stronger when the pressure difference becomes larger?
4. Why are cyclones dangerous for coastal regions?
5. Write any three safety measures during lightning.

My Learning Check

TopicI understandI need more practice
Pressure and its formula☐☐
Pressure exerted by liquids☐☐
Atmospheric pressure☐☐
Formation of winds☐☐
Storms and thunderstorms☐☐
Lightning and safety☐☐
Cyclones☐☐
Chapter 6 — Pressure, Winds, Storms, and Cyclones
Keep learning, keep questioning, and keep your curiosity alive!

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