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Grade 8 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.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 drops below the pressure underneath, and the roof is pulled down
    • b) It stays the same, and the wind lifts the roof by hitting it directly
    • c) It drops below the pressure underneath the roof, and the roof is pushed up from below
    • d) It rises above the pressure underneath the roof, and the roof is pushed up from above

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

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

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

  4. 4.Air is normally an electrical insulator, keeping opposite charges in a cloud apart. What has to happen before lightning can flash?

    • a) The rain stops, because water carries the charge away
    • b) The air cools until it turns into a conductor of electricity
    • c) The cloud touches the ground so the charges can meet
    • d) The charge builds up so much that the insulating property of the air breaks down

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

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

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

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

  7. 7.Match each name to what the chapter says it is.

    • Storm
    • Thunderstorm
    • Cyclone
    • Eye of the cyclone
    • a storm that also brings lightning and thunder
    • a spinning system of clouds, winds and rain around a very low-pressure center
    • strong winds accompanied by rain
    • the calm center, where the pressure is at its lowest

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

Answer key — Grade 8 Science — Winds, storms and cyclones

  1. 1. c) It drops below the pressure underneath the roof, and the roof is pushed up from below
  2. 2. eye
  3. 3. c) Its source of warm moist air from the ocean has been cut off
  4. 4. d) The charge builds up so much that the insulating property of the air breaks down
  5. 5. b) Thunder, as the air expands and makes a loud sound
  6. 6. 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
  7. 7. Storm → strong winds accompanied by rain; Thunderstorm → a storm that also brings lightning and thunder; Cyclone → a spinning system of clouds, winds and rain around a very low-pressure center; Eye of the cyclone → the calm center, where the pressure is at its lowest
  8. 8. b) To give electric charge an easy path into the ground