Dynamic Earth Interactive: Plate Tectonics
Grade 8 Earth Science
Name:
Core:
Date:
Instructions
This worksheet is intended to be used with the “Dynamic Earth” interactive web site at:
http://www.learner.org/interactives/dynamicearth/index.html
To complete this worksheet go to the web site at the address listed above, then follow the links.
Be sure to follow each link all the way, roll your mouse over the diagrams wherever it says to do
so, and take each “Challenge”.
Earth’s Structure
1. The outermost layer of the Earth is the _________________________. It is thickest under
the _________________________ and thinnest under the _________________________.
2. What is the mantle made of?
3. The lithosphere is made up of the _________________________ and a small part of the
_________________________
_________________________.
4. The lithosphere is divided into several constantly moving _________________________ that
hold the _________________________ and the _________________________.
5. The plates of the lithosphere move on the _________________________, which is very hot
and _________________________.
6. What does the word “malleable” mean?
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7. The outer core is the only _________________________ layer of the Earth.
8. The outer core is made up primarily of what two substances?
9. The inner core is extremely hot and _________________________. Like the outer core it is
primarily made up of _________________________ and _________________________.
Plate Tectonics
10. What evidence did Wegner find that supports the hypothesis that the Earth’s continents were
once joined in a single large landmass?
11. According to plate tectonics theory Earth’s outer layer, the __________________, is broken
into several large __________________, which hold the continents and the oceans, and are
in constant motion.
12. Plate tectonics theory explains how ____________________________________,
___________________________________, and other geologic events occur.
Plates and Boundaries
13. The Earth’s continents are constantly moving due to the motions of the _________________.
14. How does continental crust differ from oceanic crust?
15. The border between two tectonic plates is called a _________________________.
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16. List the three types of plate boundaries and describe the motions of the plates at each.
17. Where do most divergent plate boundaries occur, in the interiors of continents or in the
oceans?
18. What kind of plate boundary occurs between the Australian Plate and the Eurasian Plate?
19. In California, there is a transform boundary between the North American Plate and what
other plate?
Slip, Slide, and Collide
20. Where do most geologic events take place?
21. What is a subduction zone?
22. Where an oceanic plate collides with a continental plate, why does the oceanic crust get
pulled under the continental crust?
23. What geologic features would you expect to see near a subduction zone?
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24. A chain of islands called a _________________________ _________________________
sometimes forms above subduction zones.
25. Why do earthquakes occur at subduction zones?
26. What is a tsunami?
27. What geologic features typically form where two continental plates collide?
28. What happens when divergent boundaries occur in the middle of an ocean?
29. What forms when boundaries between continental plates diverge?
30. In a transform boundary, in which direction are the plates moving?
31. In transform boundaries, the plates can become “stuck”. What happens when the plates
suddenly become “unstuck”?
32. What is the name of the famous transform boundary that runs through California?
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