1. The Earth’s
Layers
Scientists have spent many years determining what is inside the earth. Geologists can’t use x-rays to see inside the earth or dig a hole deep enough to explore what is deep inside the Earth. They have used instruments to measure earthquake waves move through the Earth. These waves pass through different materials at different rates. By analyzing earthquake waves, geologists have theorized that the interior of the earth consists of layers.

2. Students will … illustrate the structural layers of Earth, including the inner core, outer core, mantle, crust, asthenosphere, and lithosphere. [6.10A]

3. Earth’s Layers Each layer of the Earth has its own unique properties.
There are three distinct layers – the crust, mantle, and core – which can then be subdivided into more layers.
Each layer is made up of specific elements.

4. Simple Layers Crust Mantle Core
Scientists have identified three main layers. At the center of the earth, is the core which is 750 miles in diameter. Next we find the outer core at 1,430 miles thick. Then we have the mantle at 1,800 miles. Finally, we have the earth’s crust which is very a thin layer in comparison to the rest of the earth at miles.

5. Into the Earth…

6. The Crust Outermost layer Thinnest layer and much cooler than others
2 types of crust
Oceanic (very dense, made of basalt)
Continental (less dense, made of granite)

7. Oceanic and Continental Crust
Thinnest beneath ocean and thickest beneath mountain ranges

8. The Mantle Layer beneath crust Middle layer Very thick layer
Made up of more
iron and magnesium
so is very dense
Convection currents
occur in the mantle

9. Mantle Is Divided into …
Lithosphere
Asthenosphere
Consists of the crust and the upper part of the mantle
Solid and rocky
Broken into large pieces called tectonic plates
Earthquakes can occur in the lithosphere
Made up of elements Oxygen and Silicon
Beneath the lithosphere
Partially molten
The rock is pliable or plastic-like
Rock here bends, stretches, and flows
The tectonic plates float on this layer

10. Tectonic Plates
Earth’s crust is broken into about a dozen major plates and several minor plates
These plates constantly move on top of the Asthenosphere

11. The Core Made up of the elements iron and nickel
1/3 of the Earth’s mass
The core is larger
than Mars!
The core is very
hot and dense

12. The Core is Divided Into…
Outer Core
Inner Core
The outer core is a liquid
The material of the outer core is considered molten as it is extremely hot
Less dense than the inner core
Made up of Iron and Nickel
The inner core is the most dense
It is solid even though the temperature is very hot due to the extreme pressure
The inner core is composed mostly of Iron

13. Earth’s Layers How are the Earth’s layers similar to an egg?
Shell=crust
Egg white=mantle
Yolk=core

14. Physical Structure of the Earth Layers Reviewed
Crust and Lithosphere- rigid outer layer
Mantle and Asthenosphere- solid rock that flows slowly (like hot asphalt)
Outer Core- liquid layer
Inner Core- solid, very dense

15. References http://geomaps.wr.usgs.gov/parks/pltec/#crust