Download Earth Guided Reading Notes

Ch. 21 Planet Earth Guided Reading Notes
Name ___________________________
1. Many people call the outermost layer of the Earth the crust. What is the crust called beneath the ocean?
________________________________ What is the crust called that we live on? __________________________
2. The layer beneath the crust is called the mantle. Humans have never drilled down to the mantle, so how do we
know so much about it? _______________________________________________________________________
3. Draw and label Figure 1 on page 729.
4. Caves and mines are both underground, so why is it that caves are cool and mines are hot? _________________
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5. Compare the consistency of the upper mantle versus the lower mantle. ________________________________
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6. Describe the outer core. _______________________________________________________________________
7. Describe the inner core. _______________________________________________________________________
8. Why don’t the metals in the outer core turn to gases? _______________________________________________
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9. Describe how radioactive isotopes/ radioactivity help to make the center of the Earth hot. _________________
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10. What is Alfred Wegener’s hypothesis about the continents? __________________________________________
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11. What did he call the “supercontinent?” ___________________________________
12. Describe the fossil evidence that Wegener used to back up his hypothesis. _______________________________
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13. Wegener’s evidence was good, but many scientists did not believe in this theory that the continents drifted
apart because they could not imagine how such large land masses could have moved. That is, unit the 1960’s
when what type of discoveries were made? ________________________________________________________
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14. How does the alignment of rock support the theory of moving plates? __________________________________
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What does it mean that Earth’s magnetic field has reversed direction? __________________________________
About how often does this occur? ________________________________________________________________
What is the lithosphere? _______________________________________________________________________
What are tectonic plates? ______________________________________________________________________
What is plate tectonics? _______________________________________________________________________
How fast do tectonic plates move? ______________________________________________________________
Do tectonic plate boundaries match up with continental boundaries? ______________
In what directions do plates move? ______________________________________________________________
What is the aesthenosphere? ___________________________________________________________________
How do many scientists THINK the tectonic plates move? _____________________________________________
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Other scientists think that is not enough… what else do they think contributes to the movement of the plates?
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Where do most volcanoes and earthquakes occur? _________________________________________________
What else can occur here?_____________________________________________________________________
DIVERGENT DIVIDE… What happens at divergent boundaries where two plates are moving apart from each
other? ______________________________________________________________________________________
What are mid ocean ridges? ____________________________________________________________________
How are mid-ocean ridges different from mountains on land? _________________________________________
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What feature is found in the center of a mid-ocean ridge? ___________________________________________
Which mid-ocean ridge is the most studied? _________________________________________ Where is it
located? ____________________________________________________________________________________
CONVERGENT COLLIDE… What can occur at convergent plate boundaries where two plates are pushing
together? ___________________________________________________________________________________
Describe subduction. __________________________________________________________________________
What often forms at subduction zones? ___________________________________________________________
Describe HOW islands form. ____________________________________________________________________
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Describe HOW mountains form. _________________________________________________________________
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What causes breaks in the lithosphere? ___________________________________________________________
What is a fault? ______________________________________________________________________________
Where do faults occur? ________________________________________________________________________
What is a transform fault boundary? _____________________________________________________________
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What is likely to occur along these faults? _________________________________________________________