High-speed winds over a roof create a low pressure zone above it. What happens as a result?

The roof may be blown off because pressure below is higher than above

Lightning occurs when:

Opposite electric charges in clouds (or between clouds and ground) suddenly discharge producing a bright flash

What protects buildings from lightning?

A lightning conductor—a metal rod from the top of the building to the ground

Why are overhead water tanks placed at a height?

To increase water pressure so it flows well through taps

Two pipes of different diameters filled with water to the same height produce the same bulge in attached balloons. What does this show?

Wider pipes have higher pressure

Water pressure depends on the height of the water column, not the amount (volume) of water

Narrow pipes have higher pressure

Why is the base of a dam broader than the top?

To withstand the large horizontal water pressure near the bottom where the water column is tallest

When you press a rubber sucker against a smooth surface and it sticks, what scientific principle is demonstrated?

Atmospheric pressure outside the sucker is higher than the reduced pressure inside, holding it to the surface

Sea breeze during the day blows from sea to land because:

Land heats faster than water, creating low pressure over land; cool high-pressure air from the sea blows towards land

Thunder is the sound produced by:

Lightning rapidly heating the surrounding air, causing it to expand suddenly and produce a loud sound

A cyclone forms when:

Warm moist air over oceans rises rapidly, creating a very low pressure area with spiralling high-speed winds

Why do liquids exert pressure on all sides of a container, not just the bottom?

Liquid particles move freely and push in all directions, exerting pressure on all container surfaces

It is safer to keep doors and windows open during a high-speed wind storm because:

It equalises pressure inside and outside, reducing the pressure difference that could blow roofs off

In Activity 6.6 (blowing between two balloons), they moved towards each other because:

Blowing air pushes them together

High-speed air between them created low pressure; higher surrounding pressure pushed them inward

The balloons were attracted magnetically

A soldier walks on snow with large snowshoes instead of boots. What is the scientific reason?

Larger area of snowshoes reduces pressure on snow so the soldier doesn't sink in

Land breeze at night blows from land to sea. Explain this using concepts of air pressure.

At night, the sea is warmer than land, creating low pressure over sea; cooler high-pressure air from land flows to sea

Temperature has no effect on wind

In a thunderstorm, lighter positively charged ice particles move upward and heavier negatively charged water droplets move downward. What process initially creates these charges?

Strong winds blowing upward and downward cause friction between water droplets and ice particles, generating static electric charges

Lightning charges the particles

The India Meteorological Department (IMD) issues cyclone warnings using weather satellites. How does this help reduce damage?

It prevents cyclones from forming

It allows people to track cyclone paths and make advance preparations including evacuation, reducing loss of life and property

When inflated balloons are connected by a straw to uninflated balloons, air flows until both reach the same size. What principle does this demonstrate?

Air always flows from cold to hot regions

Air moves from high pressure (inflated balloon) to low pressure (uninflated) and stops flowing when pressures equalise

Air can flow without pressure difference

A cyclone weakens after moving inland from the ocean. Why?

The cyclone's energy source—warm moist ocean air—is cut off over land, causing it to gradually lose strength

Inland areas have more friction

The Amphan cyclone of 2020 had peak wind speeds of 270 km/h. A storm surge of 3–12 metres can accompany a cyclone. What causes this surge?

Strong cyclone winds push ocean water towards the shore, creating a wall of water

Which of the following demonstrate that liquids exert pressure in multiple directions? (Select all that apply)

Water spurts from holes on all sides of a bottle

The base of a dam is broader to withstand horizontal water pressure

Overhead tanks provide water pressure in taps below

Submarines must withstand water pressure from all sides

Which of the following are safety precautions during lightning as mentioned in the chapter? (Select all that apply)

Crouch down in a low-lying open area (do not lie flat)

Avoid using an umbrella with a metallic rod

Get out of water immediately if in it

Which of the following are consequences of a cyclone reaching land? (Select all that apply)

Storm surge flooding coastal areas

Seawater contaminating freshwater sources and farmland

A mango shower (localised thunderstorm) in Kerala helps mango ripening. What series of events explains this thunderstorm's formation?

Cold air descending rapidly from the Himalayas

Warm moist air rises over heated land, creating low pressure; cooler surrounding air rushes in and also rises; water vapour condenses to form clouds; strong vertical winds create charge separation leading to thunder and lightning

Cyclone approaching from the sea

Sea breeze causing condensation

High-speed winds can blow roofs off buildings. However, opening doors and windows during such winds reduces this risk. Using pressure concepts, explain why in-depth.

Open windows let in water which cools the roof

High winds over the roof create low pressure above it; closed windows trap higher pressure inside; this large pressure difference can lift the roof; opening windows allows inside pressure to drop, equalising with outside and reducing the net upward force

Open windows make walls stronger

The roof is heavier when windows are open

Cyclones in the Northern Hemisphere spin anticlockwise while in the Southern Hemisphere they spin clockwise. This is because of:

Differences in ocean temperature

The Coriolis effect—Earth's rotation deflects moving air to the right in the Northern Hemisphere and to the left in the Southern Hemisphere

Farmers depend on mango showers in South India. These local thunderstorms are absent in the far north during pre-monsoon. What creates this regional difference?

Southern India near the equator has more intense solar heating and higher humidity, leading to stronger convection and thunderstorms before the monsoon

Wind does not reach south India

A 15 cm × 15 cm area experiences atmospheric pressure equal to the weight of a 225 kg object (~2250 N). Why are humans not crushed by this enormous pressure?

The pressure inside our bodies (from fluids and gases in tissues and organs) equals atmospheric pressure, balancing the external force

Atmospheric pressure is not real

Which of the following correctly describe the formation of a cyclone? (Select all that apply)

Warm ocean water heats the air above it, causing it to rise

Rising air creates a low pressure area that draws surrounding air inward

Condensing water vapour releases heat, fuelling further upward movement of air

Earth's rotation causes the spinning movement of air around the low pressure centre

Which of the following events in a thunderstorm occur in the correct sequence? (Select all that apply)

Land heats up causing warm moist air to rise

Rising air cools and condenses into clouds

Strong winds cause charge separation in clouds

When charges build sufficiently, lightning and thunder occur

Which of the following correctly explain how pressure is applied in everyday life? (Select all that apply)

A knife cuts better with a sharp (small area) edge because pressure is higher

Nails have pointed tips to create high pressure for easy driving into wood

Wearing broad-strapped bags is more comfortable than narrow-strapped bags

Placing cloth under loads on the head distributes pressure and reduces discomfort

Which of the following would increase the effectiveness of a lightning conductor? (Select all that apply)

Ensuring the rod extends higher than the highest point of the building

Burying the lower end deep in the ground

Painting the rod to make it visible

NCERT Solutions Class 8 Science - Curiosity Chapter 6 – Pressure, Winds, Storms, and Cyclones

Name: Pressure, Winds, Storms, and Cyclones – Class 8 Science - Curiosity
Uploaded: 2026-07-24T09:23:59+00:00
Description: This chapter explores the link between force and pressure and how they shape natural phenomena like winds, storms, lightning, and cyclones. It explains how pressure in air and liquids works, how winds form due to pressure differences, and how high-speed winds can cause storms and cyclones.

Class 8 Science - Curiosity

Last Updated: 24 July 2026

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Chapter Introduction

This chapter explores the link between force and pressure and how they shape natural phenomena like winds, storms, lightning, and cyclones. It explains how pressure in air and liquids works, how winds form due to pressure differences, and how high-speed winds can cause storms and cyclones.

हिंदी में (Hindi)

यह अध्याय बल और दाब के संबंध तथा उनके द्वारा उत्पन्न प्राकृतिक घटनाओं — जैसे हवा, तूफ़ान, बिजली और चक्रवात — को समझाता है। इसमें बताया गया है कि द्रवों और वायु में दाब कैसे कार्य करता है और वायु दाब का अंतर तूफ़ान व चक्रवात का कारण कैसे बनता है।

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Important Points

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Practice MCQ Questions (40 questions)

Q1. Pressure is defined as:

Q2. What is the SI unit of pressure?

Q3. Why does a bag with broad straps feel more comfortable than one with narrow straps (same weight)?

Q4. What is atmospheric pressure?

Q5. In which direction does air move naturally?

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Frequently Asked Questions (FAQ)

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Tough Words (Glossary)

swirling

Meaning: moving in circles through the air

अर्थ: घूमते हुए हवा में चक्कर लगाना

"Swirling leaves covered the road."

swaying

Meaning: moving slowly from side to side

अर्थ: धीरे-धीरे इधर-उधर डोलना

"Tall trees were swaying in the wind."

exert (force)

Meaning: to apply or use (force/effort)

अर्थ: बल/प्रयास लगाना

"Wind can exert a strong force on windows."

flutter

Meaning: to move or wave quickly and lightly

अर्थ: फड़फड़ाना

"Clothes began to flutter on the line."

rattle

Meaning: to make a rapid shaking sound

अर्थ: खड़खड़ाना

"The windows began to rattle during the storm."

pressure

Meaning: force per unit area

अर्थ: दाब (क्षेत्रफल पर लगने वाला बल)

"High pressure can push water out faster."

perpendicular

Meaning: at a right angle (90°) to a surface

अर्थ: लंबवत, 90° पर

"We considered only perpendicular forces."

identical

Meaning: exactly the same

अर्थ: एकदम समान

"They carried identical bags to the picnic."

strap

Meaning: a narrow strip used for carrying

अर्थ: पट्टा

"A broad strap reduces shoulder pain."

bulge

Meaning: a swelling that sticks out

अर्थ: उभार, फुलाव

"The balloon showed a bulge at the bottom."

column (of water)

Meaning: a vertical length of liquid

अर्थ: जल-स्तंभ

"A taller column creates more pressure."

vessel

Meaning: a container for liquids

अर्थ: पात्र

"Pressure depends on the height of liquid in a vessel."

overhead

Meaning: located above head level

अर्थ: सिर के ऊपर स्थित

"Overhead tanks supply water to homes."

spurt

Meaning: to gush out suddenly

अर्थ: फव्वारे की तरह निकलना

"Water began to spurt from the holes."

withstand

Meaning: to resist or endure

अर्थ: सहन करना, झेलना

"Dams are built to withstand high pressure."

atmosphere

Meaning: the layer of air around Earth

अर्थ: वायुमंडल

"The atmosphere surrounds our planet."

atmospheric pressure

Meaning: pressure exerted by the air around us

अर्थ: वायुमंडलीय दाब

"Atmospheric pressure acts in all directions."

inflate

Meaning: to fill with air

अर्थ: फुलाना

"She inflated the balloon quickly."

sucker

Meaning: a rubber cup that sticks by suction

अर्थ: रबर का चूषण कप (सकर)

"Press the sucker against the tile."

insulator

Meaning: a material that does not easily allow electricity/heat to pass

अर्थ: रोधक

"Dry air normally acts as an insulator."

magnitude

Meaning: size or amount of something

अर्थ: परिमाण, मात्रा

"The magnitude of pressure can be very large."

millibar (mb)

Meaning: a unit of air pressure equal to 100 pascal

अर्थ: मिलीबार (वायुदाब की इकाई)

"Weather reports show pressure in millibar."

hectopascal (hPa)

Meaning: a unit of pressure equal to 100 pascal

अर्थ: हेक्टोपास्कल (Pa का सैकड़ा)

"Air pressure is often given in hPa."

circulation

Meaning: continuous movement of air or liquid

अर्थ: परिसंचरण

"Warm air rises and sets up circulation."

condense

Meaning: to change from gas to liquid

अर्थ: संघनित होना

"Water vapour condenses to form clouds."

hail

Meaning: small balls of ice that fall from clouds

अर्थ: ओलावृष्टि, ओले

"The storm brought hail and strong winds."

humid

Meaning: having a lot of moisture in the air

अर्थ: आर्द्र, नमी भरा

"Storms are frequent in humid regions."

tropical

Meaning: related to warm regions near the equator

अर्थ: उष्णकटिबंधीय

"Tropical areas often see strong storms."

facilitate

Meaning: to make easier; to help

अर्थ: सुगम बनाना, सुविधा देना

"Strong winds facilitate rubbing inside clouds."

separation (of charges)

Meaning: the process of moving apart into different regions

अर्थ: विभाजन (आवेशों का)

"Charge separation occurs within clouds."

collide

Meaning: to crash into each other

अर्थ: टकराना

"Opposite charges can collide during storms."

ignite

Meaning: to catch fire or cause to burn

अर्थ: आग पकड़ना, प्रज्वलित होना

"Lightning can ignite forest fires."

precaution

Meaning: something done to prevent harm

अर्थ: सावधानी

"Take precautions during lightning."

crouch

Meaning: to bend low with the knees close to the body

अर्थ: झुककर बैठना, दुबकना

"Crouch in a low area during lightning."

lightning conductor

Meaning: a metal rod that safely carries lightning to the ground

अर्थ: तड़ित चालक

"A lightning conductor protects the building."

cyclone

Meaning: a large, spinning storm over warm oceans

अर्थ: चक्रवात

"The cyclone brought heavy rain and wind."

evaporation

Meaning: the process of liquid changing into vapour

अर्थ: वाष्पीकरण

"Evaporation takes heat from the surroundings."

rotation (Earth’s)

Meaning: spinning motion around an axis

अर्थ: घूर्णन

"Earth’s rotation makes winds spin."

eye (of cyclone)

Meaning: the calm centre of a cyclone

अर्थ: चक्रवात की आँख (शांत केंद्र)

"Winds are calm in the eye of the cyclone."

storm surge

Meaning: a rise of sea level pushed by storm winds

अर्थ: तूफ़ानी ज्वार, समुद्री उफान

"The storm surge flooded coastal villages."

contaminate

Meaning: to make impure or dirty

अर्थ: दूषित करना

"Seawater can contaminate drinking wells."

debris

Meaning: scattered pieces of broken things

अर्थ: मलबा, अवशेष

"Roads were blocked by debris after the cyclone."

outage

Meaning: a period when power or service is not available

अर्थ: बिजली/सेवा बंद होना

"Power outages lasted for days."

forecast

Meaning: a prediction of future weather

अर्थ: मौसम पूर्वानुमान

"The forecast warned of high winds."

satellite

Meaning: an object in space used for observation/communication

अर्थ: उपग्रह

"Satellites help track cyclones."

designated

Meaning: officially chosen for a purpose

अर्थ: निर्दिष्ट, निर्धारित

"Move to the designated cyclone shelter."

prone (area)

Meaning: likely to experience something

अर्थ: संवेदनशील/प्रवण (क्षेत्र)

"This is a cyclone-prone coast."

low-pressure area

Meaning: a region where air pressure is lower

अर्थ: निम्न-दाब क्षेत्र

"Wind flows toward a low-pressure area."

high-speed winds

Meaning: very fast moving air

अर्थ: अत्यधिक तेज़ हवाएँ

"High-speed winds can blow off roofs."

thunderstorm

Meaning: a storm with thunder and lightning

अर्थ: मेघगर्जन वाला तूफ़ान

"A thunderstorm drenched the town."

lightning

Meaning: a bright flash due to electric discharge

अर्थ: बिजली (तड़ित)

"Lightning lit up the night sky."

precipitation

Meaning: water falling from clouds as rain/hail/snow

अर्थ: वृष्टि (बारिश/ओले/बर्फ)

"Precipitation increased during the storm."

NCERT Solutions Class 8 Science - Curiosity Chapter 6 – Pressure, Winds, Storms, and Cyclones

Chapter Introduction

Watch Video Lecture

Important Points

Practice MCQ Questions (40 questions)

Q1. Pressure is defined as:

Q2. What is the SI unit of pressure?

Q3. Why does a bag with broad straps feel more comfortable than one with narrow straps (same weight)?

Q4. What is atmospheric pressure?

Q5. In which direction does air move naturally?

Q6. A storm accompanied by lightning and thunder is called:

Q7. What is the centre of a cyclone called?

Q8. High-speed winds over a roof create a low pressure zone above it. What happens as a result?

Q9. Lightning occurs when:

Q10. What protects buildings from lightning?

Q11. Why are overhead water tanks placed at a height?

Q12. Two pipes of different diameters filled with water to the same height produce the same bulge in attached balloons. What does this show?

Q13. Why is the base of a dam broader than the top?

Q14. When you press a rubber sucker against a smooth surface and it sticks, what scientific principle is demonstrated?

Q15. Sea breeze during the day blows from sea to land because:

Q16. Thunder is the sound produced by:

Q17. A cyclone forms when:

Q18. Why do liquids exert pressure on all sides of a container, not just the bottom?

Q19. It is safer to keep doors and windows open during a high-speed wind storm because:

Q20. In Activity 6.6 (blowing between two balloons), they moved towards each other because:

Q21. A force of 200 N is applied over an area of 4 m². What is the pressure?

Q22. A soldier walks on snow with large snowshoes instead of boots. What is the scientific reason?

Q23. Land breeze at night blows from land to sea. Explain this using concepts of air pressure.

Q24. In a thunderstorm, lighter positively charged ice particles move upward and heavier negatively charged water droplets move downward. What process initially creates these charges?

Q25. The India Meteorological Department (IMD) issues cyclone warnings using weather satellites. How does this help reduce damage?

Q26. When inflated balloons are connected by a straw to uninflated balloons, air flows until both reach the same size. What principle does this demonstrate?

Q27. A cyclone weakens after moving inland from the ocean. Why?

Q28. The Amphan cyclone of 2020 had peak wind speeds of 270 km/h. A storm surge of 3–12 metres can accompany a cyclone. What causes this surge?

Q29. Which of the following demonstrate that liquids exert pressure in multiple directions? (Select all that apply)

Q30. Which of the following are safety precautions during lightning as mentioned in the chapter? (Select all that apply)

Q31. Which of the following are consequences of a cyclone reaching land? (Select all that apply)

Q32. A mango shower (localised thunderstorm) in Kerala helps mango ripening. What series of events explains this thunderstorm's formation?

Q33. High-speed winds can blow roofs off buildings. However, opening doors and windows during such winds reduces this risk. Using pressure concepts, explain why in-depth.

Q34. Cyclones in the Northern Hemisphere spin anticlockwise while in the Southern Hemisphere they spin clockwise. This is because of:

Q35. Farmers depend on mango showers in South India. These local thunderstorms are absent in the far north during pre-monsoon. What creates this regional difference?

Q36. A 15 cm × 15 cm area experiences atmospheric pressure equal to the weight of a 225 kg object (~2250 N). Why are humans not crushed by this enormous pressure?

Q37. Which of the following correctly describe the formation of a cyclone? (Select all that apply)

Q38. Which of the following events in a thunderstorm occur in the correct sequence? (Select all that apply)

Q39. Which of the following correctly explain how pressure is applied in everyday life? (Select all that apply)

Q40. Which of the following would increase the effectiveness of a lightning conductor? (Select all that apply)