Plate Tectonics

2. The layer of hot, solid material between Earth’s crust and core.
5. Boundary A plate boundary where two plates move past each other in opposite directions.
8. The soft layer of the mantle on which the lithosphere floats.
13. The name of the single landmass that began to break apart 200 million years ago and gave rise to today's continents.
14. Boundary A boundary where two plates move toward each other.
15. The layer of rock that forms Earth’s outer surface.
16. Current The movement of a fluid, caused by differences in temperature that transfer heat from one part of the fluid to another.
18. The measurement of how much mass of a substance is contained in a given volume.
19. Core A dense sphere of solid iron and nickel at the center of Earth.

1. Boundary lithosphere are in constant motion, driven by convection currents in the mantle.
3. A rigid layer made up of the uppermost part of the uppermost part of the mantle and the crust.
4. Valleys A deep valley that forms where two plates move apart.
6. trenches: A deep valley along the ocean floor beneath which oceanic crust slowly sinks toward the mantle.
7. Drift: The hypothesis that the continents slowly move across Earth's surface
9. The process by which oceanic trench and back into the mantle at a convergent plate boundary.
10. Tectonics The theory that pieces of Earth's
11. The transfer of heat from one particle of matter to another.
12. The transfer of energy by electromagnetic waves.
17. Core A layer of molten iron and nickel that surrounds the inner core of Earth.