Earth’s Layers Notes Listen to Notes

1. Two main ways scientists collect information about the Earth is by drilling into it and by using seismic information.

2. Seismographic equipment measures the seismic or shockwaves produced by earthquakes.

3. Earth is made of three layers; the crust, the mantle, and the core.

4. The outer layer of the Earth is called the crust. Crust is CRUNCHY!

5. The deepest hole on earth is 12 kilometers or 40,000 feet deep & only goes into the crust. We have never been able to dig a hole through the crust.

6. The crust is made up of different kinds of rock, but the two main types are granite and basalt.

7. Basalt is much stronger than granite. Ocean crust is made only of basalt. (basalty)

8. Five elements make up more than 90 percent of the crust; oxygen, silicon, aluminum, iron, and calcium.  74% of the Earth’s surface is made of oxygen and silicon.  Osaic!

9. The scientific name for the crust is the lithosphere, the solid portion of the Earth. L=lithosphere, lightest, least dense.

10. The scientists believe that Earth’s crust, or lithosphere, is broken into several segments or plates.

11. The Earth’s surface can be divided into two kinds of crust, continental crust and ocean crust.

12. Continental crust is thicker but less dense. It is thickest in the mountains.

13.The temperature of the crust goes from 20 degrees Celsius (72 f) at the surface to 870 degrees Celsius at the bottom.

14. Oceanic crust is much thinner but denser than continental crust.  It averages only 5-7 kilometers thick.

The Mantle!

15. Density increases as we go deeper into the Earth. The crust is the LEAST dense layer and the inner core is the most dense.

16. The mantle is the second layer of the Earth and it is the biggest.

17. The mantle makes up 80 percent of the Earth’s total volume and 66% of it’s MASS!!!  Mantle Makes Most Mass!

18. The mantle has a lot more iron than the crust and the amount of iron increases as you go deeper. Mantle is denser than crust.

19. The top part of the mantle is soft and gooey and is called the asthenosphere. The lithosphere sort of slides on top of the asthenosphere.

20. At the top of the mantle, the temperature averages about 870 Celsius and near the bottom it reaches 2200 Celsius.

The Core!

21. The core is really two layers, an outer core and an inner core.

22. The outer core temperature goes from 2,200 Celsius on the upper edge and gets hotter the deeper you go,  up to 5,000 Celsius.

23. The outer core is liquid, very dense, molten or melted iron and nickel.

24. The inner core temperatures are believed to be about 5,000 Celsius throughout.

25. The inner core is solid iron and nickel, is the densest layer.  It is hot enough to be melted but is SOLID because of the incredible pressure on it.

26. The super heavy mass or weight of the entire is Earth is squeezing down on the inner core so strongly that it can't be melted.

27. IMPORTANT FACT! As we go deeper and deeper into the Earth, pressure and temperature and density increase!