Transcript Layers of the Earth

Layers of the Earth
Sixth Grade Science Unit
Earth’s Beginning
Earth, the largest rocky planet, was formed about 4.5
billion years ago.
 The Earth's interior is divided into four different
layers.
 It is cool on the surface but very hot deep inside the
planet.
 The center, or core, is as hot as 9000 degrees F
which is hotter than the surface of the sun.

Earth’s Interior
The Earth's interior is made of rock and metal.
 It has four main layers:
1) the inner core: a solid metal core
2) the outer core: a liquid molten core
3) the mantle: dense and mostly solid rock
4) the crust: thin rock material

Earth’s Layers

How are the earth’s
layers similar to an egg?
Shell=crust
 Egg white=mantle
 Yolk=core

Lithosphere: where crust and top of mantle meet
Asthenosphere: The asthenosphere is a portion of the
upper mantle just below the lithosphere that is
involved in the plate movements.
Lithosphere
Lithosphere
Asthenosphere
The Earth’s Surface
The Earth's surface is unique from the other planets
because it is the only one with liquid water.
 Water helps to make surface features such as rivers,
lakes and oceans.
 The moving plates of the Earth’s surface form other
surface features such as mountains, earthquakes and
volcanoes.

Interior of the Earth
Many geologists believe that as the Earth cooled the
heavier, denser materials sank to the center and the
lighter materials rose to the top.
 Because of this, the crust is made of the lightest
materials (rock- BASALTS and granites) and the core
consists of heavy metals (nickel and iron).

The Crust
The outermost layer of the Earth is the crust.
 The crust is the layer that YOU live on, and it is the
most widely studied and understood.
 In the oceans, it is about 4 miles thick.
 On the thickest continents, it extends some 40
miles into the Earth.

The Mantle
The region just below the crust and
extending all the way down to the Earth's
core is called the mantle.
 The mantle is much hotter and has the
ability to flow.

The convection current of the mantle is much like the
convection current created in a pot of boiling water.
Lithosphere
Athenosphere
The Core
Beneath the mantle is the Earth's core.
 The Earth's core consists of two layers:

 The outer core
 It flows like a liquid
 Mostly made of iron
 and a solid inner core.
 It is VERY hot!
 It is in a solid state even though it is hot enough
to be melted. This is due to the enormous
amount of pressure on it from the other layers
that lie on top.
The Core (continued)

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The Outer and Inner Cores are hotter still with
pressures so great that you would be squeezed into a
ball smaller than a marble if you were able to go to the
center of the Earth!
Because the outer core contains iron, when it flows it
generates a magnetic field.
This is the source of the Earth's magnetic field.