Name__Greg Engel___
Date_Chicks_____
Hour_Anytime___
Prerequisites;
L2.p5A
P5.p1A
P3.p8A
Earth Science
objectives
E2.3
Earth’s outer most layer, is the crust, and the uppermost part of the next layer,
the mantle, make up the earth’s “lithosphere.” (Litho=rock, sphere=round) The
lithosphere is broken up into sixteen large plates that cover the Earth’s surface.
These plates are floating and moving on a section of
the mantle called the asthenosphere. The
asthenosphere is an area in the upper mantle of the
earth's interior that demonstrates a semi plastic (or
partially molten) property called “plasticity.” This
semi plastic part of the asthenosphere is believed to
be the zone upon which the Earth’s lithospheric plates move about. The asthenosphere is
thought to be located between 45–155 miles (72–250 km)
beneath the Earth's surface.
The Athenosphere allows tectonic plates to “float”
and the
crust to
rise and
fall like
the
surface of
a giant
water bed
as mass
moves around on it. This plastic like
behavior also allows the crust to glacial
rebound when glacier ice melts.
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Open each of the following links, and prepare for the test:
http://www.pbs.org/wgbh/aso/tryit/tectonics/divergent.html
http://www.pbs.org/wgbh/aso/tryit/tectonics/convergent.html
http://www.pbs.org/wgbh/aso/tryit/tectonics/crush.html
http://www.geo.cornell.edu/hawaii/220/PRI/PRI_PT_contdrift.html
http://www.pbs.org/wgbh/aso/tryit/tectonics/transform.html
http://earthquake.usgs.gov/learn/kids/
http://www.wwnorton.com/college/geo/egeo2/content/animations/2_6.htm
http://earthquake.usgs.gov/learn/kids/become.php
http://earthquake.usgs.gov/learn/animations/
http://www.quia.com/jg/262313.html
Pick two to help you review! -http://www.quia.com/jg/262313.html
Problem:
How can the reverse plasticity of the Earth’s mantle be simulated? (As you go
down through the asthenosphere, the density increases and plasticity decreases)
Materials:
20 g cornstarch, 1 small plastic cup or
beaker and one small Erlenmeyer flask,
50 ml cold water, medicine dropper,
wooden stick.
Procedure:
1. Place a small plastic cup on the
scale and “zero” the scale. Add 20
grams of cornstarch to the beaker
or cup. Into the flask, pour 50 ml of
cold water.
2. Use the medicine dropper to
gradually add ONE DROPPERFUL
Glacial rebound of the
plastic-like Athenosphere!
of water to the cornstarch. Stir the
mixture. Do not break the stir rod.
3. Continue to add the water, ONE
DROPPERFUL at a time. Stir the
mixture after each addition. Stop adding the water when the mixture becomes slightly liquid
in appearance and difficult to stir.
4. Try to pour the mixture into your hand. Try to roll the mixture into a ball and press it.
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5. Gently push your finger through the liquid in your hand. Now poke the liquid with the same
finger very quickly (and hard). What do you observe?
___The liquid becomes very stiff when poked.____________
More observations:
1. Before the addition of water, is the corn starch a solid, liquid, or gas? __Solid____
Is the water a solid, liquid, or gas? __Liquid________
2. When you try to pour the mixture into your hand, does the mixture behave like a solid, liquid,
or gas? ___liquid_______
3. When you try to roll
the mixture into a
ball and apply
pressure, does the
mixture act like a
solid, liquid, or gas?
____Solid____
Analysis and
Conclusion:
1. How is the mixture of cornstarch and water similar to the Earth’s mantle?
Near the surface of the “crust” the asthenosphere is more liquid, as it is under more and more
pressure it turns into more solid material.
2. How might the plasticity of the mantle influence the movement of the Earth’s lithospheric
plates?
The asthenosphere allow the plates to “flow” on the
convection currents of the mantle.
3. Propose another model you could use to show how
the plasticity of the mantle allows the Earth’s
lithospheric plates to move.
The density of the plates drags them around as the
plates descend into the core.
Conclusions: This lab's purpose was to show you that a
substance can demonstrate more than one property
when physical conditions change. The asthenosphere
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is a solid that behaves like a liquid. Your model here was a liquid that could demonstrate solid
properties when put under pressure.
Honors Science Students only need to do questions and reading from this point on
http://www.sciencedaily.com/videos/2006/0803-liquid_body_armor.htm
Optional Honors Science Further reading on Plate Tectonicshttp://www.tectonic-forces.org/simplified.htm
Further exploration of plate movements;
For more information on Plate tectonics:
http://www.ucmp.berkeley.edu/geology/tectonics.html
Type in search terms: Earth crust movementhttp://www.open-video.org/results.php
http://www.geo.cornell.edu/hawaii/220/PRI/PRI_PT_contdrift.htm
l
http://earthquake.usgs.gov/learn/animations/
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