Class 8 Science Curiosity Chapter 6 Solutions (NCERT 2026–27) – Pressure, Winds, Storms, and Cyclones

These Class 8 Science Curiosity Chapter 6 solutions cover Pressure, Winds, Storms, and Cyclones from the new NCF-2023 textbook (2026–27), with every “Keep the curiosity alive” question solved step by step.

Class: 8 Subject: Science Book: Curiosity Chapter: 6 Exercise: Keep the curiosity alive (13 Qs) Session: 2026–27
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Class 8 Science Curiosity Chapter 6 Solutions – Overview

Chapter 6 of Curiosity, Pressure, Winds, Storms, and Cyclones, builds from the idea that pressure is force per unit area (SI unit pascal, Pa). It shows that liquids exert pressure in all directions and that pressure increases with the height of a liquid column, which is why overhead tanks are placed at a height. It then introduces atmospheric pressure — the pressure of the air around us — and shows that winds form because air moves from a high-pressure region to a low-pressure region. High-speed winds lower air pressure (which can blow off roofs). The chapter ends with how warm, moist air builds thunderstorms and lightning and how cyclones form over warm oceans. These Class 8 Science Curiosity Chapter 6 solutions answer every textbook question step by step.

Key Concepts & Definitions

Pressure: force acting per unit area, Pressure = Force ÷ Area. SI unit = newton/metre² (N/m²), also called the pascal (Pa). A smaller area gives higher pressure for the same force.

Liquid pressure: liquids exert pressure at the bottom and on the side walls — in all directions. The pressure increases with the height of the liquid column, not its diameter or total weight.

Atmospheric pressure: the pressure exerted by the envelope of air (atmosphere) around the Earth. Practical units are the millibar (mb) and hectopascal (hPa), each equal to 100 Pa.

Wind: moving air. Air always flows from a high-pressure region to a low-pressure region; a bigger pressure difference gives faster wind.

High-speed winds: fast-moving air is accompanied by reduced (lower) air pressure, which is why high winds can lift weak roofs.

Thunderstorm: a storm (strong winds with rain) accompanied by lightning and thunder, caused by charge separation in clouds. Cyclone: a spinning system of clouds, winds and rain with a very low-pressure eye at its centre, formed over warm ocean water.

“Probe and Ponder” & In-text Questions — Answers

Why are winds stronger on some days than on others?

ANSWERWind speed depends on the difference in air pressure between two regions. On days with a large pressure difference, air rushes faster from the high-pressure to the low-pressure area, so the wind is stronger; when the difference is small, the wind is calm.

Why are water tanks usually placed at a height?

ANSWERThe pressure of a liquid increases with the height of its column. Placing the tank high increases the water pressure at the taps, so water flows out as a strong, steady stream.

Can air pressure really crush us?

ANSWERAir does press on us with a huge force (the air column over just 15 cm × 15 cm presses with about 2250 N). We are not crushed because the pressure of fluids and gases inside our body is equal to the atmospheric pressure outside, so the two balance.

What causes storms and cyclones? If the Earth stopped rotating, would cyclones still form?

ANSWERStorms and cyclones form when warm, moist air rises and creates a low-pressure area into which surrounding air rushes, with condensing water vapour releasing heat that drives the air up further. The spinning of a cyclone is caused by the Earth’s rotation; without rotation the low-pressure system might still bring storms and rain, but it would not spin into the organised, swirling shape of a true cyclone.

Suppose you are living on the second floor of a three-storeyed building and an overhead water tank is placed on the top floor. Will you or your friend on the first floor receive a more powerful stream of tap water? Give reasons.

ANSWERYour friend on the first floor gets the more powerful stream. The first floor is lower, so the height of the water column above its tap is greater. Greater height means greater water pressure, and hence a stronger flow than on the second floor.

Table 6.1 — Explain how pressure influences each activity: driving an iron nail (by the head vs. the pointed end) and cutting an apple (sharp edge vs. blunt edge).

ANSWER Driving a nail: it is easy with the pointed end down because the tiny tip has a very small area, so the same force gives very high pressure that pierces the wood. Driving it with the broad head down spreads the force over a large area, giving low pressure, so it is difficult. Cutting an apple: the sharp edge has a very small area, so it produces high pressure and cuts easily; the blunt edge spreads the force over a larger area, giving low pressure, so it does not cut well. Conclusion: for the same force, a smaller area gives higher pressure, making such tasks easier.

Activity 6.1 & 6.2: Do liquids also exert pressure, and do they exert it on the walls of the container?

ANSWER In Activity 6.1, balloons fixed to pipes of different diameters but filled with water to the same height bulge equally. This shows the bulge depends on the height of the water column (the pressure it exerts), not on the weight or amount of water. In Activity 6.2, water spurts out of holes made in the side of a bottle, proving that liquids exert pressure not only at the bottom but also on the side walls — in fact, in all directions.

Activity 6.3 & 6.4: Does air exert pressure, and how large is atmospheric pressure?

ANSWER In Activity 6.3, more effort is needed to lift a paper plate covered with an unfolded (larger-area) chart paper than with a folded (smaller-area) one, even though the weight is the same. Since force increases with area, this shows air exerts pressure on the sheet — the atmospheric pressure. In Activity 6.4, a sucker pressed on a smooth surface sticks because air is pushed out from under it, lowering the pressure inside; the higher outside air pressure then holds it firmly, and large force is needed to pull it off. This shows how strong atmospheric pressure is.

Activity 6.5: Does the difference in air pressure cause winds to form?

ANSWERWhen an inflated balloon is joined through a straw to an uninflated one, air flows from the inflated balloon (high pressure) into the uninflated balloon (low pressure) until both reach the same pressure and size. This shows air moves from a high-pressure region to a low-pressure region — exactly how winds form.

Activity 6.6: What happens when you blow air into the narrow space between two hanging balloons?

ANSWERThe balloons move towards each other. Blowing fast air between them creates a low-pressure region in the gap, and the higher surrounding air pressure pushes the balloons inward. Blowing harder makes them come together faster. This shows that high-speed winds are accompanied by reduced air pressure.

Class 8 Science Curiosity Chapter 6 Solutions — 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

ANSWER (i) (d) equal in all three vessels. Connected vessels behave like one liquid system; liquid finds its own level, so water settles at the same height in P, Q and R regardless of their shapes. (ii) (c) M will stick but N will not stick. On a smooth surface (M), the air can be pushed out so the sucker seals and atmospheric pressure holds it. On a rough surface (N), air leaks back through the gaps, so the pressure difference is not maintained and it does not stick. (iii) (a) increase the height ‘H’ at which the tank is placed. Liquid pressure increases with the height of the water column, so raising the tank gives more pressure (and a stronger flow) at the ground-floor tap. (iv) (b) PA = PB, FA < FB. Pressure at the bottom depends only on the height of water, which is the same, so PA = PB. Vessel B is wider, so its bottom has a larger area; since force = pressure × area, the force on the wider bottom is greater, giving 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. [ ]

ANSWER (i) True. Air (wind) always moves from high pressure to low pressure. (ii) False. Liquids exert pressure on the bottom and on the side walls — in all directions. (iii) False. The eye is the calm, low-pressure centre; the strong winds and heavy rain are in the region surrounding the eye. (iv) True. A closed car (or bus) is comparatively safe during a thunderstorm; its metal body carries the charge around the occupants to the ground.

3. 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 sand? Give reasons.

ANSWER The boy sinks more when standing vertically (Fig. 6.23b). His weight is the same in both cases, but when standing his body presses on the small area of his feet, so the pressure on the sand is high. When lying down, his weight is spread over the large area of his whole body, so the pressure is low and he sinks less.

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 Given: Weight (force) = 20000 N; area of one foot = 0.25 m²; the elephant stands on 4 feet. Total area on the ground = 4 × 0.25 m² = 1 m². Pressure = Force ÷ Area = 20000 N ÷ 1 m² = 20000 N/m² (20000 Pa).

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 Boat A: Force = 5 × 700 N = 3500 N; Area = 7 m². Pressure = 3500 ÷ 7 = 500 N/m². Boat B: Force = 3 × 700 N = 2100 N; Area = 3.5 m². Pressure = 2100 ÷ 3.5 = 600 N/m². Boat B experiences more pressure, by 600 − 500 = 100 N/m².

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

ANSWER No, lightning would not occur. Lightning happens because air is normally an insulator, which lets large amounts of positive and negative charge build up and separate in the clouds. The charges are released suddenly as a bright flash only when the build-up is so great that the air’s insulating property breaks down. If air and clouds were good conductors, charges would leak away continuously and never build up to the high levels needed, so there would be no sudden discharge and no lightning.

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 Yes, both balloons will bulge. Water exerts pressure in all directions, so it presses on both balloons attached near the bottom of the bottle. They bulge equally. The pressure exerted by a liquid depends on the height of the water column above it. Both balloons are at the same height (same depth) from the water surface, so the water exerts the same pressure on each, and both bulge to the same extent.

8. Explain how a storm becomes a cyclone.

ANSWER Over warm ocean water, warm and moist air rises and creates a low-pressure area. As this air rises, water vapour condenses into raindrops and releases heat, which warms the air further and makes it rise even more, lowering the pressure still more. Air from the surrounding regions rushes in and also rises. The Earth’s rotation makes this incoming air spin around the low-pressure centre. This repeating cycle builds a very low-pressure area with high-speed winds revolving around it — the storm grows into a cyclone, a spinning system of clouds, winds and rain.

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 Side A is the land (and B is the sea). In a summer afternoon, the land heats up faster than the sea, so the warm air over the land rises and creates a low-pressure area there. Cooler air from the sea then blows towards the land as a sea breeze. Since the trees are bent away from the sea (towards A), the wind is blowing from the sea (B) towards the land (A) — so the side the trees lean towards, A, is the land.

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

ANSWER Take two thin rubber balloons and a drinking straw. Fix one (uninflated) balloon to one end of the straw. Inflate the second balloon, hold its mouth so air does not escape, and fix it to the other end of the straw. On releasing, air flows through the straw from the inflated balloon (high pressure) into the uninflated balloon (low pressure); the first balloon shrinks and the second swells until both reach the same size and the flow stops. This shows air moves from a region of high pressure to a region of low pressure.

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

ANSWER A thunderstorm is a storm (strong winds with rain) that is accompanied by lightning and thunder. Formation: When land gets heated, warm, moist air rises and creates a low-pressure area; cooler air rushes in and is heated in turn, giving continuous wind circulation. The rising air cools, and its water vapour condenses into droplets forming clouds. Strong winds blowing up and down make the water droplets and ice particles rub against each other, producing static electric charges in the cloud. Positive charges gather at the top and negative charges at the bottom. When the charge build-up is very large, the air’s insulation breaks down and charges flow suddenly, producing lightning; the air heated by lightning expands rapidly and makes the loud sound of thunder.

12. Explain the process that causes lightning.

ANSWER Inside storm clouds, strong winds blow upwards and downwards, making ice particles and water droplets rub against each other and become electrically charged. The lighter positively charged ice particles move to the upper part of the cloud and the heavier negatively charged droplets settle at the lower part, so charges become separated. Air normally acts as an insulator and keeps opposite charges apart. But when the charge build-up becomes very large, the insulating property of air breaks down and a sudden flow of charge occurs — within a cloud, between clouds, or between a cloud and the ground — producing a bright flash of light called lightning.

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

ANSWER Banners and hoardings present a large flat surface to the wind. When fast wind blows, it pushes hard against this surface and can tear or topple it. Holes let the wind pass through the banner instead of pushing fully against it. This reduces the force and pressure exerted by the wind on the banner, so it does not flap violently or get blown down and stays safely in place.

Common Misconceptions to Avoid

Watch out for these

  • Thinking liquids press only at the bottom — they exert pressure on the side walls too, in all directions.
  • Believing liquid pressure depends on the amount or weight of water — it depends on the height of the column, not the diameter or volume.
  • Confusing high-speed winds with high pressure — fast-moving air actually has lower pressure.
  • Saying the eye of a cyclone is the most dangerous part — the eye is calm; the worst winds and rain surround it.
  • Keeping doors and windows shut during high-wind storms — it is safer to keep them open so the pressure difference across the roof is reduced.
  • Thinking we should lie flat or shelter under a tall tree in lightning — instead crouch low in an open area, away from tall objects.

Extra Practice Questions

Very Short Answer Type Questions

Q1. What is the SI unit of pressure?

ANSWERNewton per square metre (N/m²), also called the pascal (Pa).

Q2. In which direction does wind blow with respect to air pressure?

ANSWERFrom a region of high air pressure to a region of low air pressure.

Q3. What is the calm, low-pressure centre of a cyclone called?

ANSWERThe eye of the cyclone.

Short Answer Type Questions

Q1. Why does a bag with broad straps feel more comfortable than one with narrow straps of the same weight?

ANSWERBroad straps spread the same weight over a larger area of the shoulders, so the pressure on the shoulders is lower. Narrow straps act on a small area, giving high pressure that hurts. Lower pressure feels more comfortable.

Q2. Why is it safer to keep doors and windows open during a storm with high-speed winds?

ANSWERHigh-speed wind over a roof creates low pressure above it while the pressure inside the house stays higher, and this difference can lift a weak roof. Keeping doors and windows open lets the wind flow through, so the pressure inside and above the roof become nearly equal, helping to prevent the roof from being blown off.

Long Answer Type Question

Q1. Describe how a cyclone forms, names its key parts, and explain why it is dangerous and how we can stay safe.

ANSWER Formation: Over warm ocean water, warm moist air rises and creates a low-pressure region. Condensing water vapour releases heat, which makes the air rise still more, lowering the pressure further. Surrounding air rushes in and, due to the Earth’s rotation, spins around the centre, building a very low-pressure area with high-speed winds revolving around it — a cyclone. Parts: The calm, lowest-pressure centre is the eye; the region around it has very strong winds and heavy rain. Why dangerous: Strong winds push seawater ashore as a surge 3–12 m high, flooding land; heavy rain causes overflowing rivers and landslides; salty seawater spoils soil and drinking water; roads block and power fails for days. Safety: Follow IMD weather alerts, keep an emergency kit ready, and move quickly to a designated cyclone shelter during a cyclone.

MCQs & Assertion–Reason

1. Pressure is defined as:

(a) force × area    (b) force per unit area    (c) area per unit force    (d) force × volume

2. The SI unit of pressure is the:

(a) newton    (b) joule    (c) pascal    (d) watt

3. The pressure exerted by a liquid at the bottom of a vessel depends on the:

(a) shape of the vessel    (b) height of the liquid column    (c) colour of the liquid    (d) width of the vessel

4. The pressure exerted by the air around us is called:

(a) liquid pressure    (b) wind pressure    (c) atmospheric pressure    (d) low pressure

5. Wind blows from a region of:

(a) low pressure to high pressure    (b) high pressure to low pressure    (c) cold to hot only    (d) high to high pressure

6. High-speed winds are accompanied by:

(a) higher air pressure    (b) reduced air pressure    (c) no change in pressure    (d) zero pressure

7. A rubber sucker sticks to a smooth surface because of:

(a) glue    (b) gravity    (c) atmospheric pressure    (d) magnetism

8. A storm accompanied by lightning and thunder is called a:

(a) cyclone    (b) thunderstorm    (c) breeze    (d) hailstorm

9. The calm, low-pressure centre of a cyclone is called the:

(a) eye    (b) tail    (c) edge    (d) front

10. The device that protects tall buildings from lightning is the:

(a) sucker    (b) barometer    (c) lightning conductor    (d) wind vane

Answer key: 1-(b), 2-(c), 3-(b), 4-(c), 5-(b), 6-(b), 7-(c), 8-(b), 9-(a), 10-(c).

For each Assertion–Reason question, choose: (A) Both true and the Reason correctly explains the Assertion; (B) Both true but the Reason is not the correct explanation; (C) Assertion true, Reason false; (D) Assertion false, Reason true.

A-R 1. Assertion: It is easier to cut an apple with the sharp edge of a knife than with its blunt edge.

Reason: A smaller area of contact produces greater pressure for the same force.

A-R 2. Assertion: Overhead water tanks are placed at a height.

Reason: Liquid pressure increases with the height of the liquid column.

A-R 3. Assertion: We are not crushed by the large force of atmospheric pressure.

Reason: The pressure of fluids and gases inside our body balances the atmospheric pressure outside.

A-R 4. Assertion: High-speed winds are accompanied by an increase in air pressure.

Reason: Air always moves from a high-pressure region to a low-pressure region.

A-R 5. Assertion: The weather at the eye of a cyclone is calm.

Reason: The eye is the region of lowest pressure at the centre of the cyclone.

Answer key: 1-(A), 2-(A), 3-(A), 4-(D), 5-(B).

Quick Revision Summary

  • Pressure is force per unit area; its SI unit is newton/metre² (N/m²), also called pascal (Pa).
  • Liquids and gases exert pressure on the walls of a container, in all directions.
  • The pressure exerted by the air around us is the atmospheric pressure.
  • Differences in air pressure cause winds to blow; air moves from high to low pressure.
  • Warm air rises, creating a low-pressure area; cooler high-pressure air moves in to take its place.
  • Thunderstorms need moisture and strong winds; up-and-down winds charge the clouds, and the collision of charges causes lightning.
  • Lightning conductors protect buildings, and the IMD monitors cyclones and thunderstorms in India.

Real-life Applications

Pressure ideas appear everywhere: school bags and bucket handles are made broad to lower pressure on the body, while knives, nails and pins are sharp to raise it. Overhead tanks are placed high for strong tap flow, dams are built with broad bases to withstand water pressure near the bottom, and rubber suckers and straws work because of atmospheric pressure. Understanding winds explains sea and land breezes, why holes are cut in banners and hoardings, why roofs need anchoring, and why the India Meteorological Department’s cyclone tracking and shelters save lives in coastal areas.

How to score full marks in this chapter

Always write the formula Pressure = Force ÷ Area, and for numericals show the units at every step (the elephant problem gives 20000 Pa; Boat B exerts 100 N/m² more than Boat A). Remember three key rules: liquid pressure depends on height, wind blows high→low pressure, and high-speed winds mean lower pressure. For storm and lightning questions, explain the steps in order — rising warm air, condensation, charge separation, discharge.

Frequently Asked Questions

What is Class 8 Science Curiosity Chapter 6 about?

It is about pressure (force per unit area), liquid and atmospheric pressure, how differences in air pressure cause winds, and how thunderstorms, lightning and cyclones form, along with safety measures.

Why do high-speed winds blow off roofs?

Fast wind over a roof creates low pressure above it while the pressure inside the house stays higher. This pressure difference can lift a weak roof, so keeping windows and doors open during storms helps prevent it.

How many questions are in the “Keep the curiosity alive” exercise of Chapter 6?

There are 13 questions, all solved on this page, along with the “Probe and ponder” prompts and the in-text activity questions.

Are these Class 8 Science Curiosity Chapter 6 solutions free?

Yes. All solutions are free and follow the official NCERT Curiosity textbook for 2026–27.

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