The document describes the four main layers of Earth: crust, mantle, outer core, and inner core. The crust is the thinnest layer and is divided into continental and oceanic crust. Below the crust is the mantle, which makes up over 80% of Earth's volume and is composed of iron-rich rock. Within the mantle are the lithosphere and asthenosphere layers. The outer core is liquid, while the inner core is solid due to extreme pressure. Seismic waves have helped scientists determine the composition of Earth's layers.

1. Erath Crust
Vivek
Srivastava

2. Earth Layers
• The Earth is divided into four main
layers.
*Inner Core
*Outer Core
*Mantle
*Crust

3. The Earth’s Crust
• The crust is the thinnest layer on Earth, 5 km to 100 km
• There are two types of crust
• Oceanic crust – made mostly of the igneous rock
basalt. Found under the ocean. Relatively thin,
5 km to 7 km. Contains more iron than the
Continental crust, therefore is more dense.
• Continental crust – made mostly of granite.
Found under the continents. Relatively thick, up
to 100 km.

4. Special parts of the Crust
• Lithosphere
• Crust is the upper part of the lithosphere.
• Broken up into large plates.
• The uppermost part of the mantle is also
part of the Lithosphere
• Asthenosphere
• Upper part of mantle, below lithosphere
• 130 – 160 km thick
• Cooler part of the mantle that the
lithosphere plates slide on top of.

7. The Earth’s Mantle
• Located directly above the outer core
• Starts below the crust
• Is the largest layer
• 80% of the Earth’s volume & 68% of Earth’s mass

8. The Earth’s Mantle
• Composed of more iron than the crust.
• Density, pressure, and temperature all increase
the deeper you go in the mantle
• Temperature ranges from 870 C – 2200 C

10. Special layers of the mantle
• Lithosphere – crust plus the upper, solid
part of the mantle. Forms plates.
• Asthenosphere – just under the
lithosphere. Slow moving “Silly putty”
layer on which the lithospheric plates
slide. (Solid rock that flows very
slowly.)

12. The Earth’s Core
The Earth’s Core
• Composed of the inner and outer core
• Both are made of iron and nickel

13. The Earth’s Outer Core
The Outer Core - Liquid
• Surrounds the inner core
• Temperature ranges from 2200 C – 5000 C
near inner core
• Molten (liquid) iron and nickel

15. The Earth’s Inner Core
The Inner Core - Solid
• Temperature reaches 5000 C
• Solid iron and nickel
• Usually both would be liquid but are solid in the
core because of the incredible pressure
• The solid core is the source of Earth’s magnetic
field

16. Magnetosphere
• The inner core and outer cores do not
turn at the same speed as the rest of
the earth.
• Causes a generator effect which
produces a magnetic field.
• It protects us from some of the sun’s
harmful radiation.

19. • What does the inside of the
Earth look like?
• How do scientists know that
there is a solid inner core?

20. Determining the composition of the Earth
• Scientists cannot see the interior of the planet,
or drill to the core, so they use seismic waves to
determine the composition of the layers.
• Seismic waves: are vibrations that are produced
when an earthquake happens.
• Seismic waves travel at different speed
depending on the composition and density of
material. Measuring these waves tells us what is
in the Earth’s layers, and how the materials
change.

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22. What do
you know
about these
layers?