Earth's Layers

3. Circular movement of molten rock in the mantle that causes tectonic activity.
5. Tectonics The theory that Earth's outer shell is divided into plates that move.
6. A measure of how much mass is contained in a given volume.
7. The thick layer of Earth between the crust and the core, composed of solid and semi-solid rock.
8. The thin, outermost layer of the Earth.
11. The innermost layer of the Earth, consisting of the outer core and inner core.
13. The rigid outer layer of the Earth, made up of the crust and uppermost mantle.
17. The force applied over a surface area, increases with depth inside Earth.
18. The thick, less dense crust that makes up Earth's continents.
19. The semi-solid, flowing layer of the upper mantle beneath the lithosphere.

1. The boundary between the crust and the mantle.
2. The solid, dense center of the Earth made mostly of iron and nickel.
4. The rate at which temperature increases with depth into the Earth.
9. Vibrations that travel through Earth, used to study its internal structure.
10. The thinner, denser crust beneath Earth's oceans.
12. (Primary Waves) The fastest seismic waves that travel through solids, liquids, and gases.
14. The liquid layer of the Earth's core, responsible for Earth's magnetic field.
15. (Secondary Waves) Slower seismic waves that only move through solids.
16. The solid part of the Earth, including the crust, mantle, and core.