Question Opening prompt 1
Why are winds stronger on some days than on others?
Steps only
A larger air-pressure difference can make wind blow faster.
Answer
Changing pressure differences cause winds of different strengths.
CLASS 8 · SCIENCE · CHAPTER 6
Pressure, Winds, Storms, and Cyclones
Simple answers to the opening prompts, six activities, the pressure comparison, all thirteen end questions, and all three projects.
29 worked answersComplete chapter answers
29 worked answers · short steps first, explanations when you need them
Probe and Ponder
Textbook pages 80
Question Opening prompt 2
Why are water tanks usually placed at a height?
Steps only
Height gives the water more pressure to flow through pipes.
Answer
Raised tanks help water flow to taps.
Question Opening prompt 3
Can air pressure really crush us?
Steps only
Pressure inside our bodies balances the air pressure outside.
Answer
Ordinary air pressure does not crush us because the pressures balance.
Question Opening prompt 4
What causes storms and cyclones? If Earth stopped rotating, would cyclones still form?
Steps only
Warm, moist rising air drives storms; Earth's rotation helps organise cyclone winds.
Answer
Storms could still form, but typical rotating cyclones need Earth's rotation.
Question Opening prompt 5
Share one question you have about pressure, wind, storms, or cyclones.
Steps only
Ask a clear question about air, pressure, weather, or safety.
Answer
Example: Why does a sea breeze blow towards land in the afternoon?
Keep the Curiosity Alive
Textbook pages 94–97
Question 1
Choose the correct statements: (i) In connected vessels P, Q, and R, where water is poured into R, where will the final water level be? (ii) Which rubber sucker sticks: M on a smooth surface or N on a rough surface? (iii) How can a tank give more pressure on the ground floor? (iv) Two vessels A and B contain water to the same level; compare pressure and force at their bottoms.
Steps only
Use water-column height for pressure, and force = pressure × area.
Answer
- (i) d
- (ii) c
- (iii) a
- (iv) a
Question 2
State whether each is true or false: (i) Air flows from higher pressure to 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.
Steps only
Recall pressure direction, the calm eye, and lightning safety.
Answer
- (i) T
- (ii) F
- (iii) F
- (iv) T
Question 3
A boy lies horizontally on loose sand in one picture and stands upright in another. In which position does he sink more, and why?
Steps only
Same force on a smaller area means greater pressure.
Answer
He sinks more while standing on his feet.
Question 4
An elephant's weight is 20,000 N. It stands on four feet, each covering 0.25 m². Calculate the pressure on the ground.
Steps only
Total area = 4 × 0.25 = 1 m²
Pressure = 20,000 ÷ 1 = 20,000 Pa
Answer
20,000 Pa
Question Question-making activity
Prepare questions using prompts such as why, when, how long, where, and why not, based on what you have learned.
Steps only
Ask clear questions about pressure, weather, and safety.
Answer
Answers vary; use evidence and reliable sources.
Question 5
Boat A has a base area of 7 m² and 5 people. Boat B has a base area of 3.5 m² and 3 people. Each person weighs 700 N. Which boat exerts more pressure on its base, and by how much?
Steps only
A: (5 × 700) ÷ 7 = 500 Pa; B: (3 × 700) ÷ 3.5 = 600 Pa
Answer
Boat B; it exerts 100 Pa more pressure.
Question 6
Would lightning occur if air and clouds were good conductors of electricity? Explain.
Steps only
Good conductors would let charge flow gradually instead of building up.
Answer
A sudden lightning discharge would be much less likely.
Question 7
Two identical balloons A and B are attached at the same height on opposite sides of a bottle. What happens when water is poured into the bottle? Do both bulge equally?
Steps only
Water presses sideways; equal depth gives equal pressure.
Answer
Both balloons bulge equally.
Question 8
Explain how a storm becomes a cyclone.
Steps only
Warm moist air rises; incoming air spins around the low-pressure centre.
Answer
Repeated rising air and Earth's rotation help form a cyclone over warm water.
Question 9
In Fig. 6.25, trees stand along the sea coast on a summer afternoon. Which side, A or B, is land? Explain.
Steps only
Afternoon sea breeze blows from sea to land; the trees lean towards A.
Answer
A is land and B is sea.
Question 10
Describe an activity to show that air flows from a region of high pressure to a region of low pressure.
Steps only
Connect an inflated balloon to an uninflated one and observe the air flow.
Answer
Air moves from higher pressure to lower pressure.
Question 11
What is a thunderstorm? Explain how it forms.
Steps only
Rising moist air forms storm clouds; separated charges produce lightning and thunder.
Answer
A thunderstorm is a storm accompanied by lightning and thunder.
Question 12
Explain the process that causes lightning.
Steps only
Separated charges suddenly flow through air, producing a bright flash.
Answer
Lightning is a sudden electric discharge in or between clouds or to the ground.
Question 13
Why are holes made in banners and hoardings?
Steps only
Holes let wind pass and reduce the force on the banner.
Answer
Perforations help stop strong winds from tearing a banner down.
Discover, Design, and Debate
Textbook pages 97
Question Project 1
Hold a strip of paper 18 cm long and 2 cm wide so it hangs freely. Predict and test what happens when you blow over it. Record and explain your observation.
Steps only
Blow across the paper and compare the pressure above and below it.
Answer
The strip rises because pressure below it is greater.
Question Project 2
Research three major cyclones in India in the last 20 years: their damage, measures taken by governments and communities, and two suggestions to reduce future losses.
Steps only
Phailin: about 9.8 lakh evacuated. Fani: over 14.7 lakh evacuated in Odisha. Amphan: NDRF helped evacuate people in Odisha and West Bengal. Improve early warnings and safe shelters.
Answer
Phailin: about 9.8 lakh evacuated. Fani: over 14.7 lakh evacuated in Odisha. Amphan: NDRF helped evacuate people in Odisha and West Bengal. Improve early warnings and safe shelters.
Question Project 3
Collect data on thunderstorm strength in different parts of India, compare the regions, and suggest reasons for the pattern.
Steps only
IMD's 2024 report found more thunderstorm days in East India than West Peninsular India during the monsoon.
Answer
East India had more recorded thunderstorm days than West Peninsular India in the 2024 monsoon report. This shows frequency, not storm strength.
Activities and Observations
Textbook pages 83–89
Question Table 6.1: Comparing pressure
Compare driving a nail by its pointed end and its head, and cutting an apple with a sharp and blunt knife. Which is easier and why?
Steps only
Compare driving a nail by its pointed end and its head, and cutting an apple with a sharp and blunt knife. Which is easier and why?
Answer
The pointed end of a nail and the sharp edge of a knife are easier to use.
Question Activity 6.1
What do balloons attached to equal-height narrow and broad pipes show? What happens when the water column is made taller?
Steps only
What do balloons attached to equal-height narrow and broad pipes show? What happens when the water column is made taller?
Answer
At the same water height, both balloons bulge about equally even though the pipes hold different amounts of water.
Question Activity 6.2
What do you observe when water flows out of holes made at the same height around a bottle?
Steps only
What do you observe when water flows out of holes made at the same height around a bottle?
Answer
Water flows outward through the side holes.
Question Activity 6.3
Why is it harder to lift a paper plate covered by a full sheet than one covered by a folded sheet?
Steps only
Why is it harder to lift a paper plate covered by a full sheet than one covered by a folded sheet?
Answer
The full sheet covers a larger area, so air pushes on a larger area of the plate.
Question Activity 6.4
Why does a pressed rubber sucker stick to a smooth surface and feel difficult to pull off?
Steps only
Why does a pressed rubber sucker stick to a smooth surface and feel difficult to pull off?
Answer
Pressing the sucker pushes out much of the air beneath it.
Question Activity 6.5
What happens when an inflated balloon is connected by a straw to an uninflated balloon?
Steps only
What happens when an inflated balloon is connected by a straw to an uninflated balloon?
Answer
Air moves from the inflated balloon, where pressure is higher, into the uninflated balloon, where pressure is lower.
Question Activity 6.6
What happens when you blow air through the space between two hanging balloons? What if you blow harder?
Steps only
What happens when you blow air through the space between two hanging balloons? What if you blow harder?
Answer
The balloons move towards each other because fast-moving air between them has lower pressure; the higher pressure outside pushes them in.