1. The Earth’s Layers

2. Standard:
Regions of different continents share similar fossils and similar rocks, which suggest that in the past those sections of continents were once joined and have since separated.

3. The Earth is divided into four layers.

4. Crust
The crust is the outer most layer followed by the lithosphere (also solid rock).

5. Crust continental crust and oceanic crust.
Is the thinnest layer and less dense than other layers.
It is composed of two rocks:
continental crust and oceanic crust.
Composed of granite, less dense.
25 miles thick
Composed of basalt, very dense
3-5 miles thick
Lithosphere

6. Mantle (located below crust)
The mantle is the largest layer of the Earth.
Consist of liquid rock
Composed of magnesium and iron.
Increase in pressure & density

7. Mantle
The movement in the mantle (convection currents) create the movement of the Earth’s plates.

8. Cooler liquid, more dense Hotter liquid, less dense
Convection Currents
Caused by the very hot material at the deepest part of the mantle rising, then cooling and sinking again. The currents occur in the asthenosphere and move the crust.
Cooler liquid, more dense
Hotter liquid, less dense

9. Occurs in liquids and gases.
Convection Current
Occurs in liquids and gases.
Hot is less dense
Cold is more dense

10. Lithosphere Plates

11. Core (outer)
The outer core is composed of liquid metals: nickel & iron.
1400 miles thick

12. Core (inner) Heaviest Layer
Temperatures so HOT and an increased amount of pressure that the metals (iron and nickel) are squeezed together and cannot move like a liquid, but are forced to vibrate and become SOLID!
Heaviest Layer

13. Today’s Assessment Question
Topic: Convection Currents
Assignment:
Can you illustrate any example of a convection current? Be sure to label your illustration.