Download The Layers of the Earth PPT

The Layers of the Earth!
Earth Layers
* The Earth is divided into four main
layers.
*Inner Core
*Outer Core
*Mantle
*Crust
The Crust
* The Earth’s crust is like
the skin of an apple. It
is very thin compared to
the other three layers.
*The crust makes up 1%
of the Earth.
* The crust of the Earth is
broken into many pieces
called plates.
The Crust
* Outer layer
* 5-100 km thick
* 2 types of crust
– Oceanic (very dense,
made of basalt)
– Continental (less dense,
made of granite)
Oceanic and Continental Crust
The Mantle
* The mantle is the
layer below the
crust.
* The mantle is the
largest layer of the
Earth.
* The mantle is
divided into two
regions: the upper
and lower sections.
The Mantle, continued
• The upper mantle is further divided into
2 parts
1) The very top of
the mantle is relatively
cold & is rigid, so it is
included with the crust
and known as the
lithosphere
The Upper Mantle, cont.
• 2) Just below the rigid lithosphere,
there lies a layer of
softer, weaker rock
that is semi-solid—
it flows VERY slowly
• It is known as the
asthenosphere
• This is where the
magma from volcanoes
comes from.
Mantle Magma &
Convection Currents
• The semi-solid rock at
the top of the
asthenosphere cools down,
becomes more dense, &
starts to sink.
• The warmer, less dense
magma rises up.
• Convection currents are
set up.
Mantle Magma &
Convection Currents
• The semi-solid rock at
the top of the
asthenosphere cools down,
becomes more dense, &
starts to sink.
• The warmer, less dense
magma rises up.
• Convection currents are
set up.
Lower Mantle
The lower mantle
The Core
* Made mostly of iron
* 1/3 of the earth’s mass
* Very hot
Outer Core
* The core of the
Earth is like a ball
of very hot metals.
* The outer core is
liquid.
* The outer core is
made up of iron and
is very dense.
Inner Core
* The inner core of
the Earth has
temperatures and
pressures so great
that the metals are
squeezed together
and are not able to
move.
* The inner core is a
solid.
Earth’s Layers
* How are the earth’s
layers similar to an
egg?
* Shell=crust
* Egg white=mantle
* Yolk=core
Physical Structure of the Earth
(5 Layers)
* Lithosphere- rigid outer layer (crust and very top
of mantle); sits on top of asthenosphere
* Asthenosphere- solid rock that flows slowly (like
hot asphalt) in the upper & middle part of the
mantle
* Mesosphere- middle layer – lower mantle rock
that is hotter but harder than asthenosphere
* Outer Core- liquid layer
* Inner Core- solid, very dense
Tectonic Plates
* Earth’s crust is broken into about 19 pieces
* These plates move on top of the
asthenosphere
Review
1) What are the four layers of the Earth?
2) The Earth’s crust is very ______?
3) The mantle is the largest layer of the Earth?
True or False
4) Is the Outer Core a liquid or a solid?
Answers!
1) Crust, Mantle, Outer Core, Inner Core
2) Thin
3) True
4) Liquid