Class 7 Science

Chapter 8: Winds, Storms and Cyclones

STAGE 0: Foundation / Basics

Moving air is called wind.

Winds, storms, and cyclones are natural phenomena caused due to changes in air pressure and temperature.

STAGE 1: Air Pressure

Air exerts pressure on everything around us.

Warm air is lighter and cold air is heavier.

Differences in air pressure cause winds to blow.

Wind

Wind blows from a region of high air pressure to a region of low air pressure.

The greater the pressure difference, the faster the wind blows.

Storms

A storm is a violent disturbance in the atmosphere.

Effects of storms:

• Heavy rain
• Strong winds
• Damage to houses and trees

Cyclones

A cyclone is a large rotating storm with very strong winds.

Cyclones are formed over warm ocean water.

Parts of a cyclone:

• Eye – calm central region
• Eye wall – strongest winds

Safety Measures During Cyclones

• Stay indoors
• Switch off electrical supply
• Do not go near fallen trees
• Listen to weather warnings

STAGE 2: NCERT Textbook Questions & Answers

Q1. What is wind?

Wind is moving air.

Q2. What causes wind to blow?

Difference in air pressure causes wind to blow.

Q3. What is a cyclone?

A cyclone is a large rotating storm with strong winds.

STAGE 3: Exam-Oriented Questions

Fill in the blanks:

• Wind is caused due to difference in air pressure.
• Warm air is lighter than cold air.

Very Short Answer:

Name the calm central region of a cyclone.
Answer: Eye

Quick Revision Points

• Moving air is called wind
• Air pressure differences cause winds
• Cyclones form over warm oceans
• Safety is important during storms