1. Geology & The Layers of the Earth A journey to the center of the Earth

2. What is Geology? Study of the solid Earth The rocks and minerals which compose the Earth The processes by which the Earth changes The history of Earth Effects on humans and life in general

4. Why do Scientists Study Geology? Enhances our understanding of how natural disasters occur Gives insights to the history of Earth To help in preserving the quality of the environment To help sustain our supplies of water, energy, and mineral resources

5. Earth’s “Spheres”

6. Lithosphere Outer, solid part of the Earth Includes the crust and upper mantle About 100 km thick

7. Layers of the Earth

8. 1) Earth’s Crust Thin, outer layer of Earth Beneath the oceans, the crust is 5 to 10 km thick Beneath the continents, the crust is 25 to 50 km thick The thickest crust is beneath mountains Consists of separate plates

9. How is ocean crust different from continental crust?

10. Critical Thinking: What can the thickness of oceanic and continental crust tell you about the ages of both?

11. Life Cycle of Oceanic Crust

12. 2) Earth’s Mantle Layer beneath the crust Is very hot More than two-thirds of the mass of Earth is in the mantle Below the lithosphere, the mantle is made up of rock that flows very slowly Heat and pressure in this layer allow the rock to flow

13. Where is the mantle located?

14. 3) Earth’s Core Innermost region of Earth Scientists believe it is mostly made of iron  Dense Two parts Outer Core Liquid About 2,250 km thick Inner Core Solid Radius of about 1,300 km

15. Which part of Earth’s core is a solid: the inner core or the outer core?

16. Critical Thinking: If it’s so hot at the inner core, why is the iron there a solid rather than a liquid, like the outer core?

17. Thickness of the Layers of Earth LayerThickness Crust5-70 km Mantle2,900 km Outer Core 2,250 km Inner Core1,300 km

18. Which is thicker, the mantle or the two core layers combined?

19. After a 3,963 mile journey, we were able to reach the center of the Earth! That’s only 1,000 miles further than the distance across the entire United States!