1. The Earth
Chapter 7 Notes

2. Layers of the Earth

3. Layers of the Earth
The Earth is divided into three layers:

4. Layers of the Earth The Earth is divided into three layers: the core
the mantle
the crust

5. Layers of the Earth
The core is divided into two layers:

6. Layers of the Earth The core is divided into two layers:
The solid inner core is made of iron.

7. Layers of the Earth The core is divided into two layers:
The solid inner core is made of iron.
The liquid outer core is made of iron and nickel.

8. Layers of the Earth The core is divided into two layers:
The solid inner core is made of iron.
The liquid outer core is made of iron and nickel.
The mantle is about 2900 km thick and is made of the same material that comes out of volcanoes.

9. Layers of the Earth The core is divided into two layers:
The solid inner core is made of iron.
The liquid outer core is made of iron and nickel.
The mantle is about 2900 km thick and is made of the same material that comes out of volcanoes.
There are two types of crust.

10. Layers of the Earth The core is divided into two layers:
The solid inner core is made of iron.
The liquid outer core is made of iron and nickel.
The mantle is about 2900 km thick and is made of the same material that comes out of volcanoes.
There are two types of crust.
Oceanic crust is made of basalt (the most common rock on Earth) and is about km thick.

11. Layers of the Earth The core is divided into two layers:
The solid inner core is made of iron.
The liquid outer core is made of iron and nickel.
The mantle is about 2900 km thick and is made of the same material that comes out of volcanoes.
There are two types of crust.
Oceanic crust is made of basalt (the most common rock on Earth) and is about km thick.
Continental crust is made of andesite and granite and is km thick.

12. Convection Cells
The crust, or lithosphere, is broken into tectonic plates that float over the mantle.

13. Convection Cells
The crust, or lithosphere, is broken into tectonic plates that float over the mantle. The plates are moved by the convection cells.

14. Convection Cells
The crust, or lithosphere, is broken into tectonic plates that float over the mantle. The plates are moved by the convection cells. When rocks are heated, they become less dense and tend to rise, creating currents within the mantle.

15. Convection Cells
The crust, or lithosphere, is broken into tectonic plates that float over the mantle. The plates are moved by the convection cells. When rocks are heated, they become less dense and tend to rise, creating currents within the mantle. The currents carry warmer rocks up and cooler rocks down.

16. Continental Drift
In 1912, German scientist Alfred Wegener proposed the Theory of Continental Drift, which says that all of the continents were once one large continent that has drifted apart. He called the super-continent Pangaea. He noted that the remains of similar plants and animals were found in Africa and South America and that there were once glaciers in places like Australia.

17. Plate Boundaries
There are three types of plate boundaries: convergent, divergent, and transform. Convergent boundaries occur where tectonic plates come together and produce mountains, volcanoes, and ocean trenches. Divergent boundaries occur where tectonic plates separate and cracks, or rifts, form. Transform boundaries occur where tectonic plates just slide past each other and can cause earthquakes.

18. Tectonic Plates
There are 16 tectonic plates.

19. Tectonic Plates
There are 16 tectonic plates. Convergent boundaries tend to be located along coastlines.

20. Tectonic Plates
There are 16 tectonic plates. Convergent boundaries tend to be located along coastlines.
Divergent boundaries tend to be located in the middle of bodies of water.

21. Tectonic Plates There are 16 tectonic plates.
Convergent boundaries tend to be located along coastlines.
Divergent boundaries tend to be located in the middle of bodies of water.
Transform boundaries

22. Ring of Fire
The Ring of Fire is almost entirely formed by convergent plates and is located along the coastlines of the Pacific Ocean. 75% of the world’s active volcanoes and 90% of the world’s earthquakes occur here.

23. Earth’s Layers