Moving plates, and the clues that they move

Grade 6 Science Worksheet - Building Confidence

Circle the best answer.

1. 1.

   Cross-section, not to scale. Ari's cross-section shows two plates with arrows pointing away from each other and magma rising between them. Which kind of boundary is it?

   • Transform: plates slide past
   • No boundary; plates don't move
   • Divergent: plates pull apart
   • Convergent: plates push together
2. 2.

   In Bo's next cross-section, the arrows point toward each other and the crust crumples upward. Which kind of boundary is it?

   • Plates drifting on liquid lava
   • Divergent: plates pull apart
   • Transform: plates slide past each other
   • Convergent: plates push together
3. 3.

   Seen from above, Kira's map shows two plates with arrows pointing in opposite directions along their shared edge. Which kind of boundary is it?

   • Divergent: plates pull apart
   • Transform: plates slide past each other
   • No boundary; the ground is just cracked
   • Convergent: plates push together
4. 4.

   The coasts of South America and Africa fit together like puzzle pieces. What does Jun conclude?

   • They are rushing toward each other right now
   • They were once joined and have moved apart
   • It is just a coincidence
   • Sea water carved them to match
5. 5.

   Map of South America and Africa today, with matching fossil marks on the two coasts across the Atlantic Ocean. Fossils of Mesosaurus, a small freshwater reptile, turn up in both South America and southern Africa. What explains this, by Luz's reasoning?

   • Its fossils floated over on pieces of driftwood
   • It swam across the Atlantic Ocean
   • It walked across a long land bridge
   • The continents were joined when it lived
6. 6.

   Fossils of the same ancient plant, Glossopteris, appear in South America, Africa, India, Antarctica and Australia. What does Milo conclude?

   • Each land grew it separately by chance
   • Its seeds blew across the oceans
   • Those lands were once joined together
   • Those lands are still joined today
7. 7.

   Noah reads the USGS page on plates. About how fast do plates move?

   • A few centimeters a year
   • A few meters a day
   • They don't move
   • A few kilometers a year
8. 8.

   Ren wonders why nobody notices the continents moving. Which answer is right?

   • They move just at night
   • They don't move
   • They move just a few centimeters a year
   • They move too fast to see
9. 9.

   An ocean plate bending down under another plate, with the place where they meet unlabeled. Where an ocean plate sinks under another plate, what forms? Tala checks the cross-section.

   • A long sliding fault
   • A lava ocean opening up
   • A tall ridge of brand-new seafloor rock
   • A deep trench, with volcanoes nearby
10. 10.

    Where two plates grind sideways past each other, what does Esme expect to find?

    • Nothing, since plates are fixed
    • Earthquakes along a long fault
    • A deep trench
    • A new ridge