Science 9 · Unit 6: Sound and space · Cambridge Lower Secondary Science Stage 9

Questions

1. 1. Which layer of the Earth is made of tectonic plates?

   • the crust
   • the mantle
   • the outer core
   • the inner core
   Check

2. 2. About 200 million years ago, Africa, South America, India and Antarctica were joined. What has happened since?

   • The oceans have flooded between them.
   • They were always separate.
   • The plates carrying them have slowly moved apart.
   • They have shrunk.
   Check

3. 3. Which of these is evidence for tectonic plates?

   • The same types of fossils are found on different continents.
   • There is more land north of the equator.
   • Each continent has different climates.
   • Some countries are hotter than others.
   Check

4. 4. Which is also evidence for tectonic plates?

   • Each continent has different climates.
   • Volcanoes and earthquakes are more likely in particular places.
   • The Moon orbits the Earth.
   • There is more land north of the equator.
   Check

5. 5. Which of these is also evidence for tectonic plates?

   • There is more land north of the equator than south of the equator.
   • The alignment of magnetic materials in rocks varies with the age of the rock.
   • Each of the continents has parts that have different climates.
   • The Moon orbits the Earth.
   Check

6. 6. What is the order of the Earth's layers from hottest to coldest?

   • mantle, inner core, outer core, crust
   • crust, mantle, outer core, inner core
   • outer core, inner core, crust, mantle
   • inner core, outer core, mantle, crust
   Check

7. 7. Which part of the Earth contains large convection currents?

   • the atmosphere
   • the mantle
   • the crust
   • the inner core
   Check

8. 8. What causes convection currents in the mantle?

   • Wind on the surface.
   • The Moon's gravity stirs the mantle.
   • Heat from the core makes rock less dense, so it rises, then cools and sinks.
   • Earthquakes push the rock around.
   Check

9. 9. How do convection currents move tectonic plates?

   • The currents pull the plates towards the core.
   • The moving mantle rock drags the plates on top of it.
   • The currents melt the plates.
   • The plates float on water.
   Check

10. 10. At the mid-Atlantic ridge, the crust is pushed up by convection. Why are North America and Europe moving apart?

    • New crust forms at the ridge and pushes the plates apart.
    • The plates are sinking into the core.
    • The Atlantic Ocean is drying up.
    • Europe is being pulled by the Moon.
    Check

11. 11. Why do most Atlantic volcanoes and earthquakes happen along the mid-Atlantic ridge?

    • It is the deepest part of the ocean.
    • It is far from land.
    • It is a plate boundary, where plates move apart.
    • The water is warmer there.
    Check

12. 12. Why did people not believe Alfred Wegener's idea of moving continents in 1912?

    • Fossils had not been found.
    • He couldn't explain what force moved them.
    • He had no maps.
    • He said the continents were made of ice.
    Check

13. 13. GPS shows North America moving west at 23 mm per year. Why is this evidence for tectonic plates?

    • It shows the Earth is shrinking.
    • It measures the continent actually moving.
    • It shows the oceans are rising.
    • It shows the GPS is broken.
    Check

14. 14. North America moves at 23 mm per year. About how long does it take to move 1 km?

    • about 23 000 years
    • about 43 years
    • about 4350 years
    • about 43 500 years
    Check

15. 15. Fossils of similar small mammals of the same age are found in South America and Africa. Why is this evidence for tectonic plates?

    • The mammals couldn't cross the ocean, so the continents must once have been joined.
    • The fossils were carried by birds.
    • All mammals look the same.
    • The mammals swam across.
    Check

16. 16. Magnetite in new rock under the Pacific is always aligned the same way, but reverses in older rock further away. What does this show?

    • Magnetite moves on its own.
    • The rocks were formed on land.
    • New rock forms at the boundary and moves away, recording reversals of Earth's magnetic field.
    • The rocks are all the same age.
    Check