Plate tectonics

4. boundary The boundary of plates that collide (also know as a destructive boundary)
6. Time Scale A way to date rock by looking at little bits of iron in the rock and use that and the fact that the earth magnetic field has shifted
8. A supercontinent that was made of all the continents
9. boundaries The boundary of plate, there are three types
10. Plastic like layer of the earth than the lithospheric plates float on
12. boundary The boundary of plates that are moving away, and then cause lava to flow through the new crack in the earths crust (also know as a constructive boundary)
14. boundary The boundary of plates that slide by each other, and causes earthquakes.
15. Wegener Continental drift was his theory

1. ridge A underwater mountain range that the plates are moving apart and new land is being made
2. One of two supercontinent that separated from pangaea
3. Layer of earth's crust that is about 100 km thick, made of the crust and the upper mantle
4. current currents in earth's mantle and is the cause of plate tectonics
5. valley A valley between highlands caused by a fault
6. The second layer of the earth, made of lava
7. Drift Wegener's theory that all the continents were once we a part of a supercontinent
11. floor spreading Hess's theory that new sea floor forms when magma is forced up by plates moving apart
13. Hess Sea Floor spreading was his theory
16. The point after a surface rock reaches its elastic limit and brake