Bell work 9/17/15
1. Get out your Earth
Layers foldable and
sheet of notebook
paper.
2. On the sheet of
notebook paper
answer the question.
What are the differences
between the three layers
of the earth?
Inside the Earth….Textbook page 393
The Core
• made of nickle and iron
• Outer core - liquid layer
• Inner core - solid
The Mantle:
• Thickest layer between 6580%.
• Takes up most of the
Earth's mass @ 80%
• 3 parts of the Mantle
Lithosphere - Upper part of
the mantle and the crust
Asthenosphere - soft plastic
like layer which tectonic
plates move on.
Mesosphere - lowest part of
the mantle and is the densest
The crust
textbook page 392
Outer most and thinnest layer
2 types
• Oceanic and Continental
Oceanic crust - more dense
Continental crust - less dense
The Physical structure of Earth
textbook pages 394-395
How do we know the Earth’s interior
consistency????
Textbook page 398
seismic waves – vibrations
caused by earthquakes
Seismologists use readings
from seismographs to
calculate the density and
thickness of each layer of
the Earth.
Intro. to Earthquakes by
Frank Gregario
tectonic plates – pieces of
the lithosphere that move
around on top of the
asthenosphere
Textbook page 396
• continental drift –
hypothesis that the
continents once formed
a single landmass,
broke up, and drifted to
their present locations.
•
Textbook page 401
Textbook page 402
magnetic reversals and
sea-floor spreading
textbook page 403
sea-floor spreading – process by which
new oceanic lithosphere forms as
magma rises toward the surface and
solidifies
molten rock contains magnetic
materials.
magnetic materials align with the
magnetic field of the Earth.
molten rock cools and these materials
are set in their direction.
Earth’s magnetic field reverses
magnetic materials align with the
magnetic field of the Earth
molten rock cools and these materials
are set in this new direction.
The Theory of Plate Tectonics
textbook pages 404-405
plate tectonics – the theory that the Earth’s
lithosphere is divided into tectonic plates that move
around on top of the asthenosphere
3 possible causes of Plate tectonics
textbook page 406
• What causes changes in density in the
asthenosphere?
– the circulation of thermal energy… as rock is
heated, it expands, becomes less dense, and
rises… as rock cools, it contracts, becomes denser,
and sinks.
How do the forces of plate
tectonics cause rock
deformation?????
• compression
• Tension
compression can cause rocks to be pushed into mountain
ranges as tectonic plates collide at convergent
boundaries.
tension can pull rocks apart as tectonic plates separate at
divergent boundaries.
folding
textbook page 409
Faulting
Strike-Slip
How mountains are formed…..
http://travel.nationalgeographic.com/travel/nationalparks/great-smoky-mountains-app/
How are mountains
formed????
when tectonic plates undergo
compression or tension
• Folded mountains – rock layers
are squeezed together and
pushed upward
• Fault-block – tension causes
large blocks of the Earth’s crust
to drop down relative to other
blocks
• Volcanic – rock that is melted in
subduction zones forms
magma then rises to the Earth’s
surface and erupts.
• uplift
• subsidence
• rift zone
All photos and information for this power point was taken from the
teacher’s edition of Holt Science & Technology, Tennessee grade 7.
Except where noted……