Chapter Three - Plate Tectonics

2. the number of main layers of the Earth
3. how much mass there is in a volume of substance
5. theory that explains the formation, movement, and subduction of Earth's plates
7. moving downward this layer is between the lithospere and the lower mantle
10. responsible for the movement of mantle rock
13. boundary where plates slide past each other
15. the oldest rock is located _____ from the mid-ocean ridge
17. things like rocks that can be held in your hand as proof
19. heat transfer through touch
20. the ocean that is expanding due to a lower number of trenches
22. fernlike plant found in Antarctica
23. an example of indirect evidence

1. force pressing on an area; increases as you move down through Earth
4. provided drilling samples to support sea-floor spreading
6. location of oceanic crust sinking back into the mantle
8. creator of the theory of sea-floor spreading
9. all lands
11. part of the core that is molten
12. creator of the idea that the continents have moved to their current locations
14. forms along divergent boundaries
16. location of the formation of new crust
18. well tested concept that explains observations
21. form when two continental plates collide
23. a device that uses sound waves to help map the ocean floor