1. Layers of the Earth

2. Earth Layers The Earth is divided into four main layers: - crust
- mantle
- outer core
- inner core

3. The Crust
Like the skin of an apple; very thin compared to other layers.
km thick
Solid rock (includes soil & water)
Makes up 1% of the Earth
Broken into many pieces called plates.

4. Two Types of Crust CONTINENTAL CRUST - 20 and 60 km thick
- made of granite, less dense
- most is above sea level
- light color, coarse
OCEANIC CRUST
- only about 10 km thick
- made of basalt, very dense
- below sea level
- dark color, fine texture

5. Crust

6. The Mantle Below the crust Semi-solid layer (magma)
Hot, iron-rich silicate rocks
Largest layer (3,000 km thick)
Divided into three parts

7. Upper Mantel
Lithosphere - a combination of the upper-most part of the mantel and the crust
Rigid (brittle)
100 km thick
Asthenosphere – soft layer below the lithosphere
Hotter; increased pressure
Less rigid (can bend like plastic)
Capable of flow
Lithos - means stone
Asthenes – means weak

8. Lower Mantel Lower mantel – a solid layer beneath the asthenosphere
Goes all the way to the Earth’s core

9. Think-Pair-Share What characteristics does the lithosphere have?
What characteristic s does the asthenosphere have?
Why does rock in the asthenosphere behave differently from the rock above?

10. Apply Your Knowledge
How much time does it take for a piece of taffy to flow when you pull on it?
How much time does it take for rock in Earth’s asthenosphere to flow?
Long time!
Rates are measured in centimeters per year

11. Heat Transfer Flow in the mantle is caused by convection currents
hot material in the mantle rises, cools and then sinks
Slow movement (like fingernail growth)

12. Outer Core Layer of liquid metal
made of iron & nickel very dense (1/3 of Earth’s mass)

13. Inner Core Dense ball of solid iron & nickel.
Pressure from upper layers squeeze the metals together, so they can’t move
Iron normally melts at 1,5350C, but in the inner core it could withstand 4,0000C with no melting

14. Earth’s Magnetic Field
Scientists believe that movements in the liquid outer core create the Earth’s magnetic field.

15. Review What are the main four layers of the Earth?
2) The Earth’s crust is very ______.
3) The mantle is the largest layer of the Earth. (True or False)
4) Is the Outer Core a liquid or a solid?

16. Answers Crust, Mantle, Outer Core, Inner Core 2) Thin 3) True
4) Liquid