Transcript Earths Layers

Earth on the Move
Earth, Inside & Out
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1.
2.
3.
The Earth is divided
into three layers
Crust
Mantle
Core
A. Crust
1.
2.
3.
4.
5.
This is the outermost layer of
the Earth and it is the layer we
walk on.
Cool, rocky skin
Temperature runs from 0-700
oC.
Average thickness is 6-70 km
If we think of the Earth as an
egg, the crust would be like
the shell on an egg.
And what type of crust would
you like with your Earth?
6. There are two
types of crust
a. Continental Crust:
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1. Makes up the
continents
2. Contains light
colored rocks such as
granite.
3. Floats high on the
mantle
b. Oceanic Crust
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1.
Makes up the
ocean floor
2. Contains the
dense rocks such as
basalt
Thinner than the
continental crust
B. Mantle
Hotter (800-4400 oC)
and denser 2900 km thick)
than the crust because the
deeper you go inside the
earth, the temperature
& pressure increases.
1.
2. Made of solid rock.
3. The Mantle is made of two zones: the
lithosphere and the asthenosphere
Mantle Zones
a. Lithosphere
 The greek prefix “litho”
means “stone” or “rock”
 Cool , rigid and connected to
the crust
 Floats on the athenosphere
(lower mantle), and slides
around very slowly.
 The upper part of the
lithosphere melts rocks,
forming a substance called
magma (remember this?).
 Broken into large and small
slabs of rock called tectonic
plates
Magma (remember this is
melted rock)
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Magma moves like hot
oatmeal.
Uneven heating causes
material in the mantle to
constantly and slowly rise &
fall in convection currents.
Convection Current:
process by which hot fluid
rises to the surface, and
then sinks again, like soup
being heated in a saucepan
b. Asthenosphere
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Greek “asthenes”
means “weak”
directly under the
lithosphere
Hotter, softer rock
that flows at a very
slow rate like tar
– The hot molten rock
rise like hot air, cools
and falls again
creating motion called
convection currents
3. Core
Deep within the Earth
is the core
 The core is made
mostly of nickel &
iron
 Twice as dense as the
mantle.
 Main source of heat
that triggers the
convection currents
 Made of two layers

The core is made of two
layers
a.
Outer core:
–
–
–
b.
molten metal
responsible for the
Earth’s magnetic field.
2300 km thick
4400-6100 oC.
Inner core:
–
–
–
solid due to pressure
2400 km in diameter
7000-8000 oC.