1. Chapter 7 Section 1
Inside the Earth

2. Compositional Layers of the Earth
(Brown)
(Gray/green)

3. Composition of the Earth:
The Earth is divided into 3 compositional layers:
Core:
iron, nickel
Mantle:
magnesium, iron, aluminum, silicon, oxygen
Crust:
oxygen, silicon, aluminum, iron, calcium, & magnesium
Crust and mantle are not very dense.
Core is denser than the crust & mantle.

4. Compositional layers of Earth

5. CRUST The outermost layer 2 types of crust 5-100 km thick
Thinnest layer
2 types of crust
Continental- thick
Oceanic-thin

6. MANTLE
2900 km thick
Layer between the crust and core
Thicker than crust
Contains most of Earth’s mass
Scientists study the mantle by looking at the composition of magma.
Magma from volcanoes gives scientists clues about the composition of the mantle.

7. How scientists see the mantle
Volcanic eruption of Mt. Etna in Sicily

8. CORE Innermost layer, below mantle to center of Earth
Made mostly of iron and nickel
Divided into two parts
Inner core—solid
Outer core—liquid

9. Physical Properties of Earth: How the layers respond to heat and pressure
Earth divided into 5 physical (mechanical) layers:
Lithosphere
Asthenosphere
Mesosphere
Outer Core
Inner Core

10. Lithosphere Outer layer of Earth
Made of crust & rigid, upper mantle (asthenosphere)
Divided into pieces called tectonic, or continental plates
Continental plates drift slowly—a few centimeters a year—on top of the mantle

11. Asthenosphere Layer below lithosphere
Pieces of lithosphere (tectonic plates) move along this layer
Made of solid rock, soft, plastic-like layer of the mantle

12. Mesosphere Below the asthenosphere Strong lower part of mantle
Extends to the Earth’s core

13. Outer Core
Liquid layer of Earth’s core
Surrounds inner core

14. Inner Core
Solid dense center

15. Quiz 1. What are the three compositional layers of the Earth?
2. What are the physical layers of the Earth?
3. Is the mantle solid or liquid?
4. What physical and compositional layers of the Earth do you live on?

16. Quiz Answers
1. What are the three compositional layers of the Earth? Crust, Mantle, and Core (CMC)
2. What are the physical layers of the Earth?
Lithosphere, Asthenosphere, Mesosphere, Outer Core, and Inner Core
3. Is the mantle solid or liquid? Liquid that can be forced to act as a solid
4. What physical and compositional layers of the Earth do you live on?
Physical: lithosphere Compositional: Crust