1. Earth’s Interior Earth’s surface has been lifted up, pushed down, bent, and broken therefore it looks much different today than it did millions of years ago. Can we dig to the center of Earth? Explain why it is or is not possible. No way! The extreme conditions within Earth’s interior prevent scientists from exploring.

2. Exploring Inside Earth Geologist use two main types of evidence to learn about Earth’s interior: direct evidence from rock samples and indirect evidence from seismic waves.

3. Direct Evidence Geologist drill holes that bring up samples of rock From the samples they make inferences about conditions deep inside Earth, where these rocks were formed. Geologist also study rocks that blast up to the surface from deep within Earth Indirect Evidence Earthquakes (EQ) produce seismic waves that scientists record to see how they travel through Earth’s interior. The speed of the waves and paths they take reveal the structure of the planet. Use this data we’ve discovered the Earth is made of layers.

4. Earth’s Layers Four main layers of the Earth: Inner Core, Outer Core, Mantle, Crust. Each layer has a different size, composition, temperature, and pressure.

5. Crust Outermost layer covering Earth Makes up only 1% of Earth’s volume Two types of crust 1.Continental 25 to 70 km thick buoyant (less dense than oceanic crust) 2.Oceanic 5 to 10 km thick dense (sinks under continental crust)

6. -Curst Continued- Temperature- range from 200  C to 400  C Composed of alumino- silicates (igneous, metamorphic, and sedimentary rocks).  70% of Earth’s surface is covered in oceans

7. Mantle Scientists divided mantle into layers based on physical characteristics of those layers. Lithosphere Uppermost part of mantle that is rigid and very similar to crust Asthenosphere This material is hotter and under increasing pressure  less rigid This layer of mantle can bend like plastic but still considered a solid Lower Mantle Solid material

8. -Mantle Continued- The mantle is between crust and outer core Entire mantle is 2, 900 km thick Temperature 500 to 900  C at the upper boundary Up to 4,000  C at the lower boundary Composed of ferro-magnesium silicates rich in iron and magnesium  Molten rock moves in a convection motion  The motion causes the movement of Earth’s tectonic plates.

9. Outer Core Just below the mantle 2, 266 km thick at outer boundary Temperature of 4, 400  C Composed of nickel-iron alloy  Consists of liquid magma- the solid inner core rotates inside outer core generating magnetic field.  Magnetic field protects Earth from harmful radiation and solar wind

10. Inner Core Just below the outer core (center most layer) Radius of 1, 220 km Temperature of 6, 400  C Composed of a solid ball of iron metal  Scientists think the inner core rotates at a different speed