Download Earths layers

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Learning objective: To be able to identify
and describe the layers of the solid Earth
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* The earth is made up of 3 layers:
- Crust – the thinnest layer
- Mantle – the thickest layer
- Core – the most dense* and is about 1/3 of the earth’s
mass. *the amount of matter in a given volume, also known as
mass density. Example of this is the number of objects in a given
volume. Number of jellybeans in a jar.
*Look up how deep each
layer is in kilometers (crust,
mantle, & core).
*What is each layer made up
of?
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* Lithosphere: cool and rigid layer (crust)
* Asthenosphere: solid rock that flows slowly
(like hot asphalt)
* Mesosphere: middle layer
* Outer core: liquid layer
* Inner core: solid, very dense
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* Inner core:
the pressure in there is so great
that iron is a solid despite the high
temperature
* Outer core: Surrounding the inner core is a
zone where temperature and pressure are so
balanced that iron is molten and exists as a
liquid.
* The difference between the inner & outer core
isn’t its composition but in its physical state:
one is solid, the other is liquid.
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* The strength of solid is controlled by both
temperature and pressure.
* When a solid is heated, it loses strength.
* When it is compressed, it gains strength.
* Differences in temperature and pressure divide
the mantle & crust into 3 strength regions.
* In the lowest part of the mantle the rock is so
compressed that it has considerable strength
even the temperature is quite high.
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* This part in within the upper mantle and also known
as the “weak sphere”
* The balance between temperature and pressure is
such that rocks have very little strength.
* Instead of being strong, like the rocks in the
mesosphere, rocks in the asthenosphere are weak
and easily deformed, like butter or warm tar.
* As far as geologists can tell the composition of the
mesosphere & asthenosphere are the same.
* The difference between the two lies in one of the
physical properties: the property changes in
strength.
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* This hard outer region, includes the uppermost
mantle and all of the crust and also known as
the “rock sphere.”
* It is important to remember that despite the
fact that the crust and mantle differ in
composition, it is rock strength, not rock
composition. That is the difference between
the lithosphere & asthenosphere.
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*How does all of this relate to
volcanic and earthquake
activity?
*For homework: answer this
question by writing 300 words.
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