Moving plates, and the clues that they move

Grade 6 Science Worksheet

Circle the best answer.

1. 1.

   Iceland sits on the Mid-Atlantic Ridge, where the land is slowly splitting apart. Which kind of boundary is Bo reading about?

   • Divergent
   • No boundary; Iceland is fixed
   • Convergent
   • Transform
2. 2.

   The Himalayas formed as India pushed into the rest of Asia. Which kind of boundary made them, in Esme's notes?

   • Divergent: plates pulling apart from each other
   • A lava ocean pushing them up
   • Convergent: two plates colliding
   • Transform: plates sliding past
3. 3.

   Map of California with the San Andreas Fault drawn and arrows on each side pointing in opposite directions along it. The San Andreas Fault in California is one of the few transform boundaries on land. What do its two plates do, by Jun's reading?

   • Pull apart to make a ridge
   • Slide past each other
   • Sit still, since faults don't move
   • Push together into a trench

4. Read this first

   Use this

   Map of an ocean floor colored in matching bands on both sides of a ridge in the middle; the color key runs from youngest to oldest.

5. 4.

   Kira's map of the ocean floor is colored by rock age, with a ridge down the middle. Where is the youngest seafloor rock?

   • In the deepest trenches
   • Near the coasts on each side of the ocean
   • At the ridge in the middle of the ocean
   • Spread evenly everywhere
6. 5.

   Map view of a ridge with matching light and dark stripes on each side, mirror images of each other. Magnetic stripes in the seafloor make the same pattern on both sides of a ridge, like a mirror. What does Milo conclude?

   • Ocean currents painted the stripes
   • Each side formed at a different coast
   • The seafloor formed at the ridge and spread both ways
   • The plates crashed together there
7. 6.

   2.5 cm each year; 100 years. The Mid-Atlantic Ridge spreads about 2.5 cm a year (USGS). How much wider does the Atlantic get in 100 years, by Noah's math?

   • No wider
   • About 250 km
   • About 2.5 m
   • About 2.5 cm
8. 7.

   2.5 cm each year; 1,000,000 years; 100,000 cm = 1 km. At about 2.5 cm a year, how far does the Atlantic widen in 1 million years? Pia works it out.

   • About 2.5 km
   • About 25 m
   • About 25 km
   • About 2,500 km
9. 8.

   2.5 cm each year; about 200,000,000 years; 100,000 cm = 1 km. Pangaea began to break up about 200 million years ago. Could 2.5 cm a year open an ocean thousands of kilometers wide in that time? Ren checks.

   • No; the Atlantic has stayed this wide
   • Yes, but just if plates move meters a year
   • No; centimeters are too small to add up
   • Yes: that adds up to about 5,000 km
10. 9.

    World map with earthquake and volcano dots crowded in lines around the Pacific Ocean. On a world map of earthquakes and volcanoes, the dots form lines around the edge of the Pacific Ocean. Why, by Tala's reasoning?

    • They mark where plates stand still
    • They mark where the mantle is liquid lava
    • They mark plate boundaries
    • They mark the hottest places on the surface
11. 10.

    Zee compares an earthquake map with a plate map. Where do most earthquakes happen?

    • Evenly everywhere on Earth
    • Where plates float on liquid rock
    • Along plate boundaries, where plates grind and push
    • In the middle of plates, far from the edges