1. The Earth Remember from vocabulary –Hydrosphere (water) –Atmosphere (gases) –Geosphere We will focus this unit on the geosphere (the solid earth)

3. Layers of the Earth 3 major zones/layers  Core  Mantle  Crust

4. The Earth’s Core

6. Broken into 2 parts: Inner Core & outer Core 1. Made of iron and nickel

7. 2. Inner core a.1300 km thick b.up to 5000 deg. C c.Solid due to high pressure d.Solid in core explains magnetic field

8. 3. Outer Core 2250 km thick 2200- 5000 deg. C Liquid iron & nickel

9. How do we know? Seismic waves: vibrations that travel through the earth –Come from explosion or earthquakes @ Earth’s surface –Scientists study how they travel through the Earth

10. Seismic Wave Paths P waves slow and bend as they move from solids to liquids; speed up and bend as they move from liquids to solids S waves disappear as they enter the outer core (liquid) Shadow Zone- region with no P or S waves

12. http://www.pbs.org/wnet/savageearth/animations/earthquakes/

14. Above the outer core 2900 km thick 80 % of Earth’s volume 68% of Earth’s mass

15. Broken into 2 parts: 1. Lithosphere (uppermost part of mantle)-solid, rigid layer 65-100km thick

16. 2. A sthenosphere 200 km thick Solid Rock can flow slowly and change shape- due to extreme heat & pressure

18. Silicon, oxygen, iron & magnesium

19. Determined by looking at ocean floor and volcanic rocks

20. Greater percentage of iron in lower mantle than upper mantle

21. Density, temperature (870- 220 deg. C), and pressure increases with depth

22. Boundary between crust and the mantle is the Moho

25. 1.Thin, outermost layer 2.All life lives on or within a few hundred meters of surface

26. 3. Made up of three types of rocks

27. Igneous rock- formed by cooling/hardening of magma

28. b. Sedimentary rock- formed by hardening of layers of sediment

29. c. Metamorphic rock- formed by changing of existing rock

30. 4. Thickness of crust varies a.Average of 8 km on the ocean floor b.Average of 32 km beneath the continents

31. 5. Ocean crust made up mostly of silicon, oxygen, iron, & magnesium The largest ophiolite is in Oman near the Persian Gulf. Photo by Peter Kelemen.

32. 6. Continental crust made up mostly of silicon, oxygen, aluminum, calcium, sodium & potassium