Tic-Tac-Know

2. Cause the plates to move; between the lithosphere and the asthenosphere
6. A plate boundary where two plates grind against each other, moving it different directions
10. A break or crack in the Earth's lithosphere along which rocks move
12. A soft layer of the mantle on which the lithosphere floats
16. Theory that pieces of the Earth's lithosphere are in motion, driven by convection currents in the mantle
17. A plate boundary where two plates move toward each other
19. Thickest layer of the Earth; it consists of two layers - the lithosphere and the asthenosphere
20. The layer of rock that forms the Earth's outer surface

1. Alfred Wegener's hypothesis that the continents were once one huge landmass but have since then drifted apart
3. The undersea mountain mountain chain where new ocean floor is produced; a divergent plate boundary
4. A plate boundary where two plates move away from each other
5. The process by which oceanic crust sinks beneath a deep-ocean trench and back into the mantle at a convergent plate boundary
7. A deep valley where two plates move apart
8. The name of the single landmass that broke apart about 225 million year
9. A deep canyon on the ocean floor
11. German Scientist who developed the Theory of the Continental Drift in 1912.
13. The process by which molten material adds new oceanic crust to the ocean floor
14. A rigid layer made up of the uppermost part of the mantle and the crust
15. Dense ball of solid material at the center of he Earth
18. A layer of molten iron and nickel that surrounds the inner core of the Earth