STUDY GUIDE: EARTH’S STRUCTURE & COMPOSITION
Vocabulary:
Core
Mantle
Crust
Silicates
Convection Currents
Lithosphere
Asthenosphere
Geology
Ch. 22.1 Earth’s Structure & Composition
1. The three main layers of Earth are the _______________ , _______________ , and
__________.
2. The layers differ in density. List the layers from the DENSEST to LEAST dense.
Densest
____________________
____________________
Least Dense
____________________
3. Explain WHY Earth has three separate layers.
While Earth was still molten …
4. What layer is being described?
Layer: Crust, Mantle, or
Core
A. ____________
Made of heavy metals like iron and nickel
B. ____________
Made of light rock with lots of silicates.
C. ____________
Made of heavy rocks that have iron and magnesium in
addition to silicates.
D. ____________
Thinnest layer.
5. Continental vs. Oceanic Crust. Fill in the chart with correct type of crust.
Continental or Ocean
Description
Crust?
A. ____________
Thicker
B. ____________
Denser; made of iron-rich basalt
C. ____________
Younger; gets recycled – renewed and destroyed.
Mantle: Circle the correct word to complete the sentence.
6. Mantle rocks are (more / less) dense than crustal rocks because they have more iron.
7. The upper mantle is (rigid / liquid / soft) rock that makes up the plates.
8. The lithosphere is made up of the crust and the (upper mantle/ lower mantle/ outer
core).
9. All of the plates on the planet make up the (asthenosphere / lithosphere / mesosphere).
10. Convection currents of hot rock that moves like taffy are found in the (lithosphere /
asthenosphere/ mesosphere).
Core: Circle the correct word to complete the sentence.
11. The outer core is (liquid / solid / gas) iron due to the high temperatures.
12. The inner core is (liquid / solid / gas ) iron due to high pressures.
True or False? If false correct the statement.
13. ______________
core.
14. ______________
We study Earth’s interior by analyzing samples of the mantle and
15. ______________
The crust is the layer under the greatest pressure.
Temperatures increase as you move from crust to core.
Label the layers of Earth in the practice diagram in your notes.
Continental Crust; Oceanic Crust; Asthenosphere; Lithosphere; Outer core; Inner core
Be able to identify what each layer is made of (composition) and any key features (liquid, makes
up plates, has convection currents, etc,)
ocean
Moho
Upper Mantle
Mesosphere = lower mantle
Liquid
Solid
Explaining Convection Currents
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
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Convection currents are loops of moving fluid (rock or gas).
They move because of differences in density (heavy things sink and light things float).
Differences in density are caused by differences in temperature (Warm things are less dense; cooler
things are compact or dense)
Complete the sentence with the correct word in the pair.
1. Rock near core (heats up/cools down) and becomes (less dense/more dense).
2. Hot rock (rises/sinks) to crust.
3. Rock near crust (heat up/cool down)and becomes (less dense/more dense).
4. Cool rock (rises/sinks) back to the core.
Place the number from the list above (#1, #2, #3, and #4) in the location where it is happening
from the picture.