Plate Tectonics

2. a rigid layer made up of the uppermost part of the mantle and the crust
5. the soft layer of the mantle on which the lithosphere floats
9. a break or crack in Earth's lithosphere along which the rocks move
10. the direct transfer of energy through space by electromagnetic waves
12. the hypothesis that the continent slowly move across Earth's surface
13. the layer of hot, solid material between Earth's surface and core
15. a plate boundary where two plates move toward each other
16. a plate boundary where two plates move past each other in opposite directions
17. a plate boundary where two plates move away
18. a well-tested concept that explains a wide range of observations
20. the amount of mass of a substance in a given volume; mass per unit volume
21. a usually light-colored rock that is found in continental crust

1. the theory that pieces of Earth's lithosphere are in constant motion, driven by continental currents in the mantle
3. the direct transfer of thermal energy from one substance to another substance that it's touching
4. a large stream of moving water that flows through the oceans
6. Vibrations that travel through Earth carrying the energy released during an earthquacke
7. the force exerted on a surface divided by the total area over which the force is exerted
8. a dark, dense, igneous rock with a fine texture, found in oceanic crust
11. the name of the single landmass that broke apart 200 million years ago and broke into today's continents
14. the process by which molten material adds new oceanic crust to the ocean floor
19. the layer of rock that forms Earth's outer surface