1. Hook!

2. What is the theory of plate tectonics?
It is the scientific belief that Earth's surface is broken into a number of shifting slabs or plates.

3. Pangaea the Supercontinent
Pangaea comes from the Greek word meaning “all lands“
Pangaea is the hypothetical supercontinent that included all the land masses on Earth

4. Plate Tectonics

5. What is Plate Tectonics
The Earth’s crust and upper mantle are broken into sections called plates
Plates move around on top of the mantle like rafts

7. What is the Lithosphere?
The crust and part of the upper mantle = lithosphere
miles thick
Less dense than the material below it so it “floats”
Broken into tectonic plates

8. What is the Asthenoshere?
The plastic layer below the lithosphere = asthenosphere
The plates of the lithosphere float on the asthenosphere
The rock is soft and weak because it is close to melting.

9. Layers of the Earth

10. Key Terms
Inner core – a solid sphere of iron and nickel at the Earth’s center
Outer core – the layer of molten metal (nickel and iron) that surrounds Earth’s inner core
Mantle – the layer of rock between Earth’s outer core and crust
Crust – a thin outer layer of rock above Earth’s mantle (includes all dry land and ocean basins)

11. The thin crust, or outer layer of the earth is made mostly of rock
The thin crust, or outer layer of the earth is made mostly of rock. The thickness of this layer varies from 3 to 34 miles. Below the crust is the mantle. - The mantle is about 1,800 miles thick and made mostly of solid rock. - It is the thickest layer of the Earth. - The mantle is also very hot - about 5,400 degrees F in some spots. The center of the earth is called the core. - It is about 2,200 miles thick. - The core is extremely hot - about 7,200 degrees F. The core is further divided into an inner core and an outer core. - The outer core is a liquid layer of melted nickel and iron. - The inner core is made of solid nickel and iron.

12. Questions... What is the theory of plate tectonics?
What is the lithosphere?
What is the asthenosphere?
What is the connection between the two?
What are the two types of plates?

13. Causes of Plate Tectonics

14. Convection Currents
Hot magma in the Earth moves toward the surface, cools, then sinks again.
Creates convection currents beneath the plates that cause the plates to move.

16. Questions... What causes plates to move?
How is a convection current formed?