1. Earth’s Internal Heat

2. If you think about a volcano, you know Earth must be hot inside
If you think about a volcano, you know Earth must be hot inside. The heat inside Earth moves continents, builds mountains and causes earthquakes. Where does all this heat inside Earth come from?

3. So Earth started out with a lot of heat.
Earth was hot when it formed. A lot of Earth’s heat is leftover from when our planet formed, four-and-a-half billion years ago.
So Earth started out with a lot of heat.

4. Earth makes some of its own heat
Earth makes some of its own heat. Earth keeps a nearly steady temperature, because it makes heat in its interior.

5. The process by which Earth makes heat is called radioactive decay
The process by which Earth makes heat is called radioactive decay. Uranium is a special kind of element because when it decays, heat is produced. It’s this heat that keeps Earth from cooling off completely.

6. Earth’s core temperature is estimated to be around 5,000 to 7,000 degrees Celsius.
That’s about as hot as the surface of the sun, but vastly cooler than the sun’s interior.

7. THE EARTH’S LAYERS

8. Relative Densities of Earth’s layers
Continental Crust: 2.7 to 3.0
Oceanic Crust: 3.0 to 3.3
Asthenosphere (Mantle) 3.3 to 5.7
Outer Core (liquid): 9.9 to 12.2
Inner Core (solid): 12.6 to 13.0

9. Thickness of the Earth’s Layers

10. Temperature of the Earth’s Layers

11. Crust The crust is less than 1% of Earth by mass.
Cold, thin, brittle outer shell made of rock.

12. Mantle Made of solid rock and it is hot
It is composed of three parts lithosphere, asthenosphere, and mesosphere.

13. Lithosphere, Asthenosphere

14. Mesosphere

15. Core two parts outer core and inner core
Dense metallic center of the Earth

16. Outer Core
Molten metal

17. Inner Core
Solid metal
Composed primarily of Fe with some Ni. Represents 1.7% of earth’s mass. Temp is near 7000K but material is solid because of intense pressure. Average density is 13.5 g/cc.

18. Heat flows in two different ways within the Earth.

19. Conduction Heat is transferred through rapid collisions of atoms.
Heat flows from warmer to cooler places until all are the same temperature.
The mantle is hot mostly because of heat conducted from the core.

20. Convection
the movement caused within a fluid by the tendency of hotter and therefore less dense material to rise, and colder, denser material to sink under the influence of gravity, which consequently results in transfer of heat.

21. Convection