Winds, Storms and Cyclones

• (a) Wind is moving air.
• (b) Winds are generated due to uneven heating on the earth.
• (c) Near the earth's surface warm air rises up whereas cold air comes down.
• (d) Air moves from a region of high pressure to a region of low pressure.

1. By observing the direction of dry leaves moving on the ground.
2. By holding a piece of paper or cloth in hand and seeing which way it blows.
3. By using a wind vane.

1. It is difficult to ride a bicycle against the wind.
2. Leaves of trees flutter when wind is blowing.
3. Blowing air into a balloon makes it expand.

No, I would not buy such a house. Ventilators are essential because warm air rises up and goes out through ventilators. If there are no ventilators, the warm and stale air will remain inside the house, making it uncomfortable.

Air exerts pressure. High-speed winds can tear the loose banners. Holes are made to allow air to pass through them, reducing the air pressure on the banner and preventing it from tearing or blowing away.

1. Help them shift to a safer place (e.g., Cyclone shelter).
2. Help them shift their essential goods and domestic animals.
3. Provide them with phone numbers of emergency services (Police, Fire brigade, Medical).

1. Listen to TV/Radio warnings carefully.
2. Store enough drinking water and food.
3. Keep emergency numbers ready.
4. Identify safe shelter nearby.

(iii) Amritsar (Because it is far away from the sea. Cyclones affect coastal areas).

(i) In winter the winds flow from the land to the ocean. (Correct).

The centre of a cyclone is a calm area. It is called the eye of the storm. It is free of clouds and has light winds.

• Wind: Moving air is called wind.
• Pressure: Air exerts pressure. High speed winds are accompanied by reduced air pressure.
• Movement: Air moves from the region of **High Pressure** to the region of **Low Pressure**.
• Heating: Warm air expands and becomes lighter. Hence, warm air rises up and cool air moves down to take its place.

• Pole vs Equator: Equator gets maximum heat. Warm air rises. Cool air from 0-30 degree latitude moves in. At poles, air is cold, it flows towards warmer latitudes.
• Land vs Water:
  • **Summer:** Land heats faster. Wind blows from Ocean to Land (Monsoon winds bringing rain).
  • **Winter:** Land cools faster. Wind blows from Land to Ocean.

• Thunderstorm: Developed in hot, humid tropical areas (like India). Upward rising winds carry water droplets -> they freeze and fall -> friction causes lightning and sound.
• Cyclone: A low pressure system with very high speed winds revolving around it.
  • **Formation:** Heat from condensation warms air -> Air rises -> Low pressure -> More air rushes in.
  • **Structure:** Centre is calm (**Eye**). Surrounded by violent winds and thick clouds.

• A dark funnel shaped cloud that reaches from the sky to the ground.
• Violent and destructive.
• Speed can be up to 300 km/h.

• Anemometer: Instrument used to measure wind speed.

• Cyclones are known by different names:
  • **Hurricane:** American continent.
  • **Typhoon:** Philippines and Japan.
• In India, the coastline is vulnerable to cyclones, particularly the East Coast (Odisha, Andhra Pradesh).
• Storm Surge: Sea water entering low lying coastal areas due to low pressure in the eye of the cyclone.