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Year 9 Science — Winds, storms and cyclones

Trace a wind back to a difference in air pressure, and follow the chain from a rising column of warm air to a thunderstorm and a cyclone.

Name: ________________________

  1. 1.A lightning conductor is a metallic rod fixed to a building, pointed at the top and buried deep in the ground at the bottom. What is it for?

    • a) To attract the charge away from the ground into the sky
    • b) To give electric charge an easy path into the ground
    • c) To stop lightning forming in the clouds above the building
    • d) To store the charge safely inside the building

  2. 2.High-speed winds blow across the roof of a house. What happens to the air pressure above the roof, and why can that lift a weak roof off?

    • a) It stays the same, and the wind lifts the roof by hitting it directly
    • b) It rises above the pressure underneath the roof, and the roof is pushed up from above
    • c) It drops below the pressure underneath, and the roof is pulled down
    • d) It drops below the pressure underneath the roof, and the roof is pushed up from below

  3. 3.A cyclone that has come ashore gradually weakens. Why?

    • a) Buildings on land block the wind and slow it down
    • b) The Earth rotates more slowly over land than over sea
    • c) The land is colder than the sea, so it freezes the cyclone
    • d) Its source of warm moist air from the ocean has been cut off

  4. 4.Put the steps that end in a flash of lightning back into the order the chapter gives them.

    • Strong winds rub water droplets against ice particles
    • The insulating property of air breaks down
    • Charge separates, leaving the lower part of the cloud negative
    • A bright flash of lightning is seen
    • The ground below becomes positively charged

  5. 5.Wind circulation goes round and round. Starting from Warm air rises, put the loop back into order.

    • Warm air rises
    • A low-pressure area is left behind
    • That air is heated in its turn
    • Cooler air from around it rushes in

  6. 6.The region of lowest pressure at the centre of a cyclone, where the wind is calm while the surrounding region is battered, is called the ___ of the cyclone. Give the one word.

  7. 7.You are caught outdoors as a thunderstorm arrives. Sort these against the chapter's advice.

    Groups: Safer during lightning · To be avoided during lightning

    • Crouching down in a low-lying open area
    • Standing under a tall tree
    • Sheltering inside a car
    • Using an umbrella with a metallic rod
    • Lying down flat on the ground

  8. 8.Lightning heats the air around it very rapidly. What does that produce?

    • a) A second flash a moment later
    • b) Hail, as the heated air freezes on cooling
    • c) Rain, as the heated air condenses
    • d) Thunder, as the air expands and makes a loud sound

Answer key — Year 9 Science — Winds, storms and cyclones

  1. 1. b) To give electric charge an easy path into the ground
  2. 2. d) It drops below the pressure underneath the roof, and the roof is pushed up from below
  3. 3. d) Its source of warm moist air from the ocean has been cut off
  4. 4. 1. Strong winds rub water droplets against ice particles 2. Charge separates, leaving the lower part of the cloud negative 3. The ground below becomes positively charged 4. The insulating property of air breaks down 5. A bright flash of lightning is seen
  5. 5. 1. Warm air rises 2. A low-pressure area is left behind 3. Cooler air from around it rushes in 4. That air is heated in its turn
  6. 6. eye
  7. 7. Crouching down in a low-lying open area → Safer during lightning; Sheltering inside a car → Safer during lightning; Standing under a tall tree → To be avoided during lightning; Using an umbrella with a metallic rod → To be avoided during lightning; Lying down flat on the ground → To be avoided during lightning
  8. 8. d) Thunder, as the air expands and makes a loud sound