Plate Tectonics

7. core a layer of molten iron (Fe) and nickel (Ni) that surrounds the inner solid core of the Earth
8. a trace of an ancient organism that has been preserved in rock
9. the layer of hot, solid material between Earth's crust and core.
10. valley a deep valley where two plates move apart
12. current the movement of fluid, caused by differences in temperature, that transfers heat from one part of the fluid to another
13. the transfer of heat within a material or between materials that are touching
14. the name of the single land mass that broke apart and gave rise to today's continents
15. drift the hypothesis that the continents slowly move across Earth's surface
16. A rigid layer made up of the uppermost part of the mantle and the crust.
18. the transfer of energy through space

1. the layer of rock that forms Earth's outer surface.
2. boundary a plate boundary where two plates move away from each other
3. trench a deep valley along the ocean floor beneath which oceanic crust slowly sinks toward the mantle
4. the transfer of heat by movement of fluid
5. ridge an undersea mountain chain where new ocean floor is produced (usually at a divergent boundary)
6. Weak, partially melted layer composed of semi-molten rocks
11. boundary a plate boundary where two plates move toward each other
14. tectonics the theory that pieces of Earth's lithosphere are in constant motion, driven by convection currents in the mantle
17. core a dense sphere of solid iron (Fe) and nickel(Ni) at the center of the Earth