Chapter 6: Pressure, Winds, Storms, and Cyclones
Original notes — ready CBSE (NCERT, English Medium) • Class 8 • Science • Book: Curiosity
Chapter 6: Pressure, Winds, Storms, and Cyclones — EG's own notes, in simple words
Book: Curiosity (CBSE, Class 8) | Chapter 6 | Medium: English
Diagram (labels are printed on the image): Diagram (labels are printed on the image): a cyclone seen from above — swirling winds around a calm central eye. A general picture, not a weather map from the book.
Trees bending in a strong storm wind. A general picture about storms, not a book scene.
What the chapter is about
Air has weight, and it presses on everything around us. This push of air is called atmospheric pressure. We do not feel it because the pressure inside our bodies balances it. When air is heated, it rises, and cooler air rushes in to take its place — this moving air is wind.
Winds are named by where they come from, and their speed is measured by an anemometer. Unequal heating of the Earth's surface creates differences in air pressure, and air always moves from high-pressure areas to low-pressure areas. The monsoon winds, which bring rain to India, are a famous example of large-scale wind patterns.
When winds become very strong and spin around a low-pressure centre, they form a storm. Over the sea, such a storm can grow into a cyclone, with a calm centre called the eye and very strong winds around it. Cyclones bring heavy rain and flooding, so warnings, safe shelters and preparedness save lives.
What you should learn
Notice what atmospheric pressure is, why winds blow, how wind speed is measured, and how a cyclone forms and why warnings matter.
Key Terms
- Atmospheric pressure — The pressure exerted by the weight of the air around us.
- Wind — Moving air, caused by differences in air pressure from unequal heating.
- Anemometer — An instrument used to measure the speed of wind.
- Cyclone — A large rotating storm system with strong winds around a low-pressure centre, formed over warm seas.
- Eye — The calm, clear centre of a cyclone, surrounded by the strongest winds.
Remember
- Air exerts pressure on everything; we do not feel it because our body pressure balances it.
- Wind blows from high-pressure areas to low-pressure areas.
- An anemometer measures wind speed; a barometer measures air pressure.
- A cyclone has a calm eye in the centre and very strong winds around it.
Exam Tip / Common Mistake
Common mistake: saying wind blows from low pressure to high pressure. It is the opposite — air moves from high pressure towards low pressure, like air rushing out of a balloon.
Chart / Table: Wind and storms at a glance
| Point | Detail |
|---|---|
| High pressure | Cool, heavy air sinking; air moves outwards |
| Low pressure | Warm air rising; air moves inwards |
| Wind | Air moving from high to low pressure |
| Storm | Very strong winds with rain, thunder or lightning |
| Cyclone | Rotating storm over warm seas; calm eye in the centre |
Practice set — try it yourself
- What is atmospheric pressure?
Hint: Think about the weight of air. - Why does wind blow?
Hint: Think about high and low pressure. - What does an anemometer measure?
Hint: Think about wind. - What is the eye of a cyclone?
Hint: Think about the calm centre. - Why are cyclone warnings important?
Hint: Think about safety and shelter.
Questions with Answers
- Why do we not feel atmospheric pressure?
Air presses on us from all sides, and the pressure inside our bodies balances the pressure outside. Because the pressures are equal, we do not feel the weight of the air. - How are winds formed?
The Sun heats the Earth's surface unevenly. Warm air rises, creating low pressure, and cooler, heavier air from high-pressure areas moves in to replace it. This moving air is wind. - What is a cyclone and how does it form?
A cyclone is a large rotating storm that forms over warm seas when warm, moist air rises rapidly and surrounding air rushes in and starts spinning. It brings very strong winds and heavy rain. - What is the difference between a storm and a cyclone?
A storm is a general term for violent weather with strong winds and rain. A cyclone is a particular kind of large, rotating storm system formed over the sea, with a calm eye at its centre. - What safety steps should be taken during a cyclone warning?
Listen to official warnings, move to a safe shelter, stay away from the seashore and weak buildings, keep drinking water and medicines ready, and do not go out until the warning is lifted.
How to use this page: Read the summary, say the Key Terms in your own words, then try the practice set without looking. Use the Questions with Answers to check yourself afterwards. Ask your teacher or parent to check your answers.