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Class 8 Science: Pressure, Winds, Storms, and Cyclones, 8 practice questions with answers

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These are 8 practice questions on the sixth chapter of the new NCERT Class 8 Science textbook, Curiosity, called Pressure, Winds, Storms, and Cyclones. Each has a short answer and the textbook page it comes from. They cover pressure as force per unit area, the size of air pressure, pressure in a liquid, why air moves, fast winds and low pressure, why thunder comes after the flash, the harm a cyclone leaves behind, and the eye of a cyclone. For the force side of this topic, see our Class 8 Force and Pressure guide. Try each question before you read the answer.

These questions are our own, drafted with AI help. Every fact was checked against the page it cites by a test script, but no practising teacher has reviewed them yet. If you find a mistake, please tell us.

What the chapter says you need

Facts from the NCERT textbook (Curiosity, Grade 8, Chapter 6, printed pages 80 to 97):

Pressure

Question 1. You push a drawing pin into a soft board with a force of 20 N. The flat head under your thumb has an area of 0.0001 m², and the point's area is one thousandth of that. (a) What pressure does your thumb feel? (b) How many times larger is the pressure under the point? (c) Why is the pin made with a broad head and a sharp point?

Answer: (a) 200,000 Pa; (b) 1000 times; (c) to keep the pressure low on the thumb and high on the board. (a) Pressure = force ÷ area = 20 N ÷ 0.0001 m² = 200,000 N/m², that is 200,000 Pa. (b) The same 20 N acts on the point too, but on an area 1000 times smaller, so the pressure is 1000 times larger: 200,000,000 Pa. (c) A small area gives a large pressure, which lets the point go into the board easily. A large area spreads the same force, so the head does not hurt your thumb. (Pressure as force per unit area, pages 81 to 83.)

Question 2. The air presses on one side of a window pane 20 cm × 20 cm with a force of about 4040 N. (a) What pressure does the air exert on the pane, in pascals? (b) Write this pressure in millibars and in hectopascals.

Answer: (a) 101,000 Pa; (b) 1010 mb, which is also 1010 hPa. (a) 20 cm = 0.2 m, so the area of the pane is 0.2 m × 0.2 m = 0.04 m². Pressure = force ÷ area = 4040 N ÷ 0.04 m² = 101,000 Pa. (b) One millibar is 100 Pa, and so is one hectopascal, so this is 101,000 ÷ 100 = 1010 mb, or 1010 hPa. (Pressure as force per unit area, pages 81 and 82; units of air pressure, page 87.)

Question 3. A fish tank has a flat floor 0.5 m long and 0.4 m wide. The water in it weighs 1200 N. (a) What pressure does the water exert on the floor of the tank? (b) The same water is poured into a tank with straight sides and a floor of 0.3 m². Is the pressure on the floor more or less now? Explain in two ways.

Answer: (a) 6000 Pa; (b) less, 4000 Pa. (a) Floor area = 0.5 m × 0.4 m = 0.2 m². Pressure = 1200 N ÷ 0.2 m² = 6000 Pa. (b) Pressure = 1200 N ÷ 0.3 m² = 4000 Pa, which is less. One way to see it: the same weight is spread over a larger area. The other: in the wider tank the same water stands lower, and a liquid's pressure depends on the height of its column. (Pressure as force per unit area, pages 81 and 82; liquid pressure and the height of the column, page 84.)

Air on the move

Question 4. A football is pumped hard. When its valve is opened, air rushes out with a hiss. (a) Why does the air move out and not in? (b) When does the air stop coming out? (c) When would the air come out faster: just after opening the valve, or near the end?

Answer: (a) the pressure inside is higher than outside; (b) when the pressures become equal; (c) just after opening. (a) Air always flows from where the pressure is higher towards where it is lower. The pumped football has air at a higher pressure than the air around it, so air flows out, as it does from a punctured bicycle tube. (b) The flow continues only while the pressure inside is higher. It stops when the pressure inside equals the pressure outside. (c) The speed of the escaping air is higher when the pressure difference is higher, which is just after the valve is opened. (Air moves from high to low pressure, pages 87 to 89.)

Question 5. During a storm, a very strong wind blows past the outside of a closed room, while the air inside the room is still. (a) On which side of the window glass is the air pressure lower? (b) Which way is a weak window pushed?

Answer: (a) outside; (b) outwards. (a) Fast-moving air is accompanied by a lower pressure, so the side where the wind rushes past, the outside, has the lower pressure; the still air inside keeps the higher pressure. (b) A push always goes from the higher pressure towards the lower, so a weak window is pushed outwards. (Fast winds and low pressure, pages 89 and 90.)

Thunderstorms and cyclones

Question 6. In a thunderstorm you see a flash of lightning and hear the thunder 6 seconds later. (a) What makes the sound of thunder? (b) Why do you hear the thunder after you see the flash? (c) Sound travels about 340 metres in a second through air. Roughly how far away was the lightning?

Answer: (a) air heated suddenly by the lightning; (b) light travels much faster than sound; (c) about 2 km. (a) Lightning heats the air around it very quickly, so the air expands suddenly and makes the loud sound of thunder (page 91). (b) and (c) go beyond this chapter: the flash and the thunder are made at the same moment, but light reaches you almost at once, while sound is far slower. (c) In 6 seconds sound covers about 6 × 340 = 2040 m, so the lightning was about 2 km away. (Thunder, page 91; the speeds of light and sound are not in this chapter.)

Question 7. A cyclone has crossed a coastal district, and its winds have now died down. According to the chapter, give three kinds of harm the people there may still be facing, and what causes each.

Answer: for example, flooding, spoilt water and farmland, and blocked roads with no power. Floods: the strong winds push sea water onto the shore as a wall of water, which can flood the coast and even places far from the sea, and the heavy rain can make rivers overflow and set off landslides. Spoilt water and land: sea water that rushes inland can make drinking water unsafe, and its salt makes the soil less fertile, so crops suffer. Blocked roads and power cuts: fallen trees and debris block roads, so help cannot reach people easily, and the power can stay off for days. (Cyclone damage, page 93.)

Question 8. A weather map of a storm over the sea shows pressure readings of 1010 mb at its outer edge, 1000 mb further in and 990 mb at its centre. (a) Where is the eye of this cyclone, and what is the pressure there? (b) In which direction does the air move between the edge and the centre? (c) Why does a cyclone slowly weaken after it reaches land?

Answer: (a) at the centre, where the pressure is lowest, 990 mb; (b) inwards, from high to low pressure; (c) its supply of moist air is cut off. (a) The pressure in a cyclone is lowest at its centre, which is called the eye; on this map that is the 990 mb reading. (b) Air moves from higher to lower pressure, so it flows in from the 1010 mb edge towards the 990 mb centre, where warm moist air rises; the Earth's rotation makes the moving air spin. (c) A cyclone gets its energy from warm, moist air rising over the ocean. Over land that source of moist air is cut off, so it gradually loses strength, though it can still cause great damage on the way. (Cyclones, pages 92 and 93.)

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Sources

All opened and read on 2 November 2026. Page numbers are the printed page numbers of the textbook; printed page = PDF page + 79 for this chapter.

The facts are from the textbook pages above. The questions, answers and checks are our own. This guide is general information; follow your teacher and the textbook.