Download Ch. 4 Plate Tectonics This is a satellite image of the San Francisco

Warm-up: If you journeyed to
the center of the Earth, what do
you think you would observe
along the way?
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Draw an illustration of your journey in your
science journal.
Ch. 7 Plate Tectonics
This is a satellite image of the San Francisco Bay area. The row of lakes below marks the
line of the San Andreas fault, a crack in Earth's crust. (New Theory)
Standard
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S6E5.a – Compare and contrast the
Earth’s crust, mantle, and core including
temperature, density, and composition. (p.
190-193)
Essential Questions
 How do scientists know what’s inside the Earth?
 How do the layers change as you descend into the
Earth?
 Why is there a magnetic field around the Earth?
What You Will Learn
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Identify the layers of the Earth by their
chemical composition & physical
properties.
Explain how scientists know about the
structure of Earth’s interior.
7.1 Inside of the Earth
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Discover Activity
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Canisters with different
items
What is inside?
Guess what is inside
by shaking, rolling, etc
Discuss with your
team and jot
observations on paper.
Do not open until told
to do so.
Finding Indirect Evidence
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Geologists use an
indirect method of
studying Earth’s
interior.
Hanging a picture on
a wall
Geologists use
seismic waves.
Finding Indirect Evidence
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Seismic waves - A
vibration that travels
through Earth carrying
the energy released
during an earthquake.
Seismographs measure
seismic waves which can
tell the distance and
travel times to calculate
the density & thickness of
each physical layer.
A Journey to the Center of the
Earth
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Book written in 1864
Scientists knew
nothing at that time.
Was the Earth hot,
cold, solid, or hollow?
A Journey to the Center of the
Earth
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You would need a vehicle that could travel
through solid rock.
The vehicle would carry scientific
instruments to record changes in
temperature and pressure as you descend
toward the center of Earth.
Temperature
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As you start to tunnel beneath the surface, you
might expect the rock around you to be cool. At
first, the surrounding rock is cool.
At 20 meters…getting warmer
Every 40 meters…goes up 1 degree Celcius.
Pressure
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During your journey to the center of Earth,
your instruments also record an increase
in pressure in the surrounding rock. The
deeper you go, the greater the pressure.
Why do you think this is the case?
Inside the Earth
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Scientists think about the physical layers
in two ways:
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Chemical composition
Physical properties
The Chemical Composition
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Three main layers
make up Earth's
interior: the crust,
the mantle, and the
core.
The Crust
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Outermost layer of the
Earth
5-100 km thick
Less than 1% of Earth’s
mass
Temp – 0-1000 degree
C
Thinnest layer like an
onion
Two types
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Continental crust
Oceanic crust
The Crust
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Both types are
made of:
Oxygen - O
Silicon – Si
Aluminum – Al
The Crust
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The oceanic crust is
denser and has twice
as much:
Iron – Fe
Calcium – Ca
Magnesium - Mg
The Crust
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Oceanic crust is made up
of mostly basalt (A).
Basalt is dark, dense, and
has a fine texture.
Continental crust is
mainly made up of granite
(B). Granite forms
continents, is less dense,
large crystals, light
colored, and coarsegrained.
The Mantle
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Between the crust and
core
Never been visited.
Volcanoes on the surface
and underwater
observations have given
scientists many clues on
the composition.
Some material gets
pushed up to the surface,
allows direct observation
of rock composition
The Mantle
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67%of Earth’s
mass
2900 km thick
Denser than crust
due to magnesium
content
Temperatures1000-3700 degrees
Celsius
The Core
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The Earth’s core
consists of two parts a liquid outer core
and a solid inner core.
Iron and nickel
(metals) make up
both parts of the core.
Makes up 1/3 of
Earth’s mass.
The Core
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Radius of 3,430 km
Temperatures in
the core range
from 3,700-7000
degrees Celsius
It is as hot as the
sun’s surface!
The Physical Structure of the
Earth
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Divided into five
layers
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Lithosphere
Asthenosphere
Mesosphere
Outer Core
Inner Core
Lithosphere
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The outermost,
rigid layer of the
Earth.
Made of two parts
Crust and upper
part of mantle
Divided into tectonic
plates
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Asthenosphere
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Plastic layer of the
mantle on which
pieces of the
lithosphere move.
Made of solid rock
that flows very
slowly.
Mesosphere
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Strong, lower part
of the mantle.
Extends from the
bottom of the
asthenosphere to
the Earth’s core
Outer Core
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The Earth’s core is
divided into two
parts:
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Outer core - liquid
Inner core
Inner Core
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Solid, dense center
of our planet that
extends from the
bottom of the outer
core to the center
of Earth, which is
about 6, 380 km.
Earth’s Magnetic Field
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Currents in the liquid outer
core force the solid inner
core to spin at a slightly
faster rate than the rest of
the planet.
These currents in the outer
core also create Earth's
magnetic field, which
causes the planet to act like
a giant bar magnet.
Earth’s Magnetic Field
Earth’s Magnetic Field
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This concept is important because it is yet
another way scientists gather information
about Earth’s history.
Since the magnetic field is present, it helps
people navigate around the world and find
their way back home.
Later in the unit, we will discuss how the
magnetic field serves as evidence for seafloor spreading.
Show What You’ve Learned
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Review activity, Promethean board.
Work with your partner to complete the
graphic organizer on the
chemical/compositional layers of the earth