Transcript PHYS111_23 - MrLaFazia.com

Conceptual Physics
THURSDAY November 11th, 2010
LESSON GOALS:
• Go over “Quiz” (Homework) after collecting
• Respond to Alfred Wegener WebQuest questions
• Take notes on some evidence for plate tectonics
• Take notes on what happens at plate boundaries
• (TIME PERMITTING) Complete exploration lab using GoogleMaps and other
online resources
• If we do not get to this exploration lab, today, then we will roll it over
to the next class.
• Recite poem Continental Drift
http://mrlafazia.com/PHYS111/lessons/201011Fall/PHYS111_23.ppt
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Review: Uni. Grav. Quiz/HMWK
(Collect quiz/homework for grading).
“The mass of a certain planet is 2x1020 kg. The
planet has a diameter of 6x105 m. How much
does a person weigh on the surface of this
planet if they have a mass of 75 kg”?
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WebQuest: Alfred Wegener
Answer the questions on the following slide in your
groups. While it may prove useful for each
individual to write down group responses, I only
want 1 paper turned into me (make sure all names
are on this paper).
You exploration throughout this WebQuest will allow
you to uncover many important facts regarding
Plate Tectonics and the Theory of Continental Drift!
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WebQuest: Alfred Wegener
1) Who was Alfred Wegener?
2) What prompted him to consider the hypothesis of continental drift?
3) What was his hypothesis of continental drift?
4) About how long ago did Pangaea exist?
5) What evidence did he use to support his ideas? You should be able to find 4 or 5 different
evidences that he used.
6) What was the reaction when he presented his hypothesis to the scientific community?
7) What was the aspect of the Continental Drift Hypothesis that Wegener couldn’t explain? (This
thing that couldn’t be explained lead other scientists to disbelieve Wegener’s hypothesis).
8) When and how did Wegener die? When did the Theory of Plate Tectonics become an assumed
truth?
9) What new evidence was discovered in the 1950’s that lead scientists to re-think Wegener’s
hypothesis, and eventually accept his ideas? (Hint: the ideas weren’t accepted until the 60’s).
10) What was the technology that lead to this discovery? (Hint: think Navy).
11) What is now the accepted theory for the “thing” that Wegener couldn’t explain?
12) Was Pangaea the “beginning” of the continents on our planet? (Hint: supercontinent cycle).
13) What is paleomagnetism, and how does it help support the idea of sea floor spreading?
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Notes: Evidence for Plate Tectonics
Here is some of the evidence in support of Plate Tectonics:
1.
2.
Puzzle-Piece globe (especially with continental shelves considered)
Species and fossils on different continents that match where “puzzlepiece globe” would have lined up
3. Rocks (by age and type) appearing on would-be-paired continents
4. Mineral deposits (e.g., coal or salt mines) cut along continent edges
5. Ancient mountain chains on different continents (once together)
6. Glacial “etching” along different continents as if they were once
together
7. Glacial deposits along equator (too hot for glaciers!)
8. Coral reefs in Antarctica (too cold for that type of ecosystem!)
9. Earth has a magnetic field (hints at convection to drive tectonics)
10. Multiple types of “boundary phenomena” (earthquakes, volcanoes, &tc)
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Discussion/Notes: Plate Boundaries
• I will draw out the major types of plate boundaries, below, that
occur between the different sections of the lithosphere (both
oceanic crust and continental crust).
• I am assigning a powerpoint online as “homework” to review,
since it provides much better pictures than the ones I will draw.
(Just go to the “studentaccess” folder on mrlafazia.com instead
of writing this all down!)
http://mrlafazia.com/studentaccess/Plate_Tectonics_UofBristol_LaFaziaModified.ppt
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Exploration Lab: GoogleMaps
•
As with the WebQuest, you may all want to have this in your notes somewhere, but I only
want 1 paper with all group members’ names turned in for grading, please.
• Go to maps.google.com and choose the “satellite” view. Using
your internet resources as references, find where the Hawaiian hot
spot is, where the San Andreas fault line is, and where the MidAtlantic midocean ridge is. (In the process, you will need to define
those 3 terms and include them in your report).
– Discussion Questions:
• “In which direction is the tectonic plate on which Hawaii is
situated likely moving”?
• “Of what significance is the San Andreas fault line”?
• “How far South and North does the Mid-Atlantic Ridge
extend”?
• “What is the Ring of Fire”?
• “If new crust is forming at the Mid-Atlantic Ridge, why isn’t
the Earth getting bigger”?
• “What is meant by the Super-Continent Cycle”?
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Poem:
Continental Drift, by D. LaFazia
The continents move all the time,
And are never truly still.
We feel and see their movement all the time,
When earthquakes rage and higher grows hill,
And the old volcanoes blow their tops,
And the cracks of doom pour forth their smoke,
And the Earth does crack and groan.
Continental Drift reveals the rift,
Between land and land,
And sea and land,
And even sea and sea.
When land plates converge,
There will emerge,
A mountain of some form.
The thick plates rise up,
And push and bend,
And fold upon themselves,
Upended, lifted; glorified struggle.
At times land plates will diverge,
But don't sing a dirge,
For new land is being formed there.
Where land and ocean meet,
They do compete,
If they are coming back together.
The ocean loses when they lock horns.
The crust subducts and melts;
Volcanoes are formed.
At times we see that land crust
Butts up against its denser cousin.
Oceanic crust and land may transform the coastline,
By moving past (it's a blast) very fast;
In a short time, then locking in again.
Stresses cause a slip-strike to release,
It's pent-up elastic potential energy,
As King Kinetic causes destruction and confusion.
Ah, that California coastline (to name one).
Another common tectonic play,
Shows two ocean plates running away
From each other, diverging slowly,
Where mid-ocean ridges are formed and growing.
This story really has no end,
And the beginning is not always clear.
But one thing's for sure, tho' we won't live to see,
Pangaea isn't the first and won't be the last
Supercontinent formed on this Earth...another's yet
to be.
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Looking Ahead:
• Next class we will take a “deeper” AND “far-reaching”
look at Earth Science (oh yes, there is a double pun
there—think Mag-Field!)
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