Download Inside the Earth

Inside the Earth
As you read pages 96-102 “Note What You Have Learned”
Composition of the Earth
Crust
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Mantle
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Outermost layer
5-100 km thick
Thinnest layer
Two types
o Continental
 Similar to granite
 About 30 km thick
o Oceanic
 Similar to basalt
 5-8 km thick
 Denser than continental
crust
Layer between the crust and core
Extremely thick compared to the
crust
o 2,900 km thick
Contains most of the Earth’s mass
Similar to the mineral olivine
o Large amounts of iron and
magnesium
Core
Made mostly of iron
Small amounts of nickel
Maybe sulfur and oxygen
Extends from the bottom of the
mantle to the center of earth
 6,856 km in diameter
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If you could burrow to the center of the Earth, what
would you expect to happen to the pressure, the
temperature and the solidity of matter? Each
successive layer will
A. become hotter, have higher pressure and become
more liquid
B. become cooler, have higher pressure and become
hard
C. become hotter, have lower pressure and become
more liquid
D. become hotter and have higher pressure; the
solidity of layers will depend on temperature and
pressure
The Structure of the Earth
 Divided into 5 main physical layers
Lithosphere
 “rock
sphere”
Asthenosphere
 “weak sphere”
Mesosphere
 “middle
sphere”
Outer core
Inner Core
 Outermost, rigid layer
 Two parts
o The crust
o The rigid upper part of the
mantle
 Divided into pieces called
tectonic/lithospheric
plates
 Soft layer of the mantle
 Pieces of the lithosphere move
on it
 Made of solid rock that flows
slowly
 Strong, lower part of the mantle
 Extends down to the Earth’s
core
Liquid layer
Lies beneath the mantle
Surrounds the inner core
Solid, dense center
Extends to the center of the
Earth
 Hotter than the surface of the
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Sun
Sketch the Structure of the Earth
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Name each layer
Identify each layer as solid, liquid or viscous (having
relatively high resistance to flow- think of pancake
syrup that has been chilled in the refrigerator)
As you move from the outside in, what pattern do
you notice?
Explain why the inner core is not liquid.
Tectonic Plates = Lithospheric Plates
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Lithosphere is a giant jigsaw puzzle
10 plates cover the Earth
Not all are the same
Mountain ranges on continental crust have very deep roots
Continental crust stands higher than oceanic crust because it is both thicker and less dense
Mapping the Earth’s Interior
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We know so much about the mantle and core because of earthquakes.
Seismic waves are vibrations that travel through the Earth.
Seismic waves travel at different speeds depending on the material they travel through.
Seismographs record the different arrival times of seismic waves.
Scientists use these measurements to calculate the density and thickness of each physical
layer of the Earth.
QAR each section review question. Complete sentences are necessary for credit. You goal is to
provide complete responses the follow standard conventions of writing.
1. Oceanic crust is thin and dense compared with continental crust. Continental crust and granite
have similar compositions, and oceanic crust and basalt have similar compositions.
2. The lithosphere is rigid and is divided in tectonic lithospheric plates. The asthenosphere is a
layer of soft mantle material that flows very slowly.
3. Scientists measure different speeds at which seismic waves travel through different parts of
the Earth. This indicates the density and thickness of each layer the wave passes through.
4. The crust and lithosphere are the outer most layers of the Earth, but the lithosphere includes
the crust and the rigid, uppermost part of the mantle.
http://www.pbs.org/wgbh/aso/tryit/tectonics/#
World Map – identify volcanoes and earthquakes
Volcanoes
earthquakes
http://www.pbs.org/wgbh/aso/tryit/tectonics/#
World Map – identify volcanoes and earthquakes
Volcanoes
earthquakes