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Earth the Biography: Volcanoes SOLUTION
Answer the following questions while watching the video.
1. In what country is Dr. Iain Stewart visiting that he needs body guards for? Why is he there?
He is in Ethopia, he has body guards because it is bandit country, to observe Mt. Erta Ale (alley)
2. What is Iain observing at “Smoking Mountain”? Give details of his observation.
The permanent lake of molten lava. He watches the process of lava pooling up, cooling on the
surface, then “flowing” across the surface and sinking back down. Earth’s surface in miniature.
3. Give a detailed explanation of Iain’s theory on why there is so much heat in the center of our
planet? It began when the Earth was created (4.5 billion years ago). Heat was created by the
collision of rocks (asteroids and meteors) and underground radioactive decay. When the surface
cooled, the heat was trapped underground in a hot molten core.
4. What is Iceland’s geography like? What causes it to be like this? Give specific details.
Iceland is very volcanically active, with bubbling hot springs over 100F. There is a lava plume
under Iceland only 12 miles below the surface. It is 370 miles deep 100 miles wide.
5. What is the significance of the huge crack that runs through Iceland. What is it evidence of?
It is where two tectonic plates meet runing unbroken under the Atlantic Ocean across the US to
California, The North American Plate. Tectonic plates and the movement of land masses.
6. Because of plate tectonics what will eventually happen to the world we know today?
The continents will move and possibly reform into one super continent.
7. What has the collisions of continental plates created?
Mountain ranges are created, like the Southern Alps in New Zealand 300 miles long. Created by
the collision of the Pacific and Australian Plates, which began 10s of millions years ago
8. How do earth quakes occur? Give details. What forces are at work?
Earth quakes are the “growing pains” of the collisions of tectonic plates. Plates push against
each other, get stuck, pressure builds up and when it is released, land “snaps” back into place.
9. What forces tear down the mountains that have been created by geologic forces?
Water in the form of rain from oreographic lift. Rivers erode the rock.
10. What happens to the sediment that is washed off of the worlds mountains?
It flows into rivers and streams, then into the oceans.
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11. What two forces are working to build up and tear down the surface of our planet?
Water and wind tear down the Earth’s surface. Volcanoes push molten rock back onto the
surface and the collision of tectonic plates creates mountains. Otherwise - water world.
12. Based on the theory of evolution, what theories are given to explain the roll of volcanoes in
the forming of life on Earth? Explain the processes in detail. Volcanic activity created the
chemicals and thermal pools that may have provided “stuff” that resulted in the creation of life
on our planet. Also, hydro thermal vents in the ocean, produce the heat and chemicals.
13. Compare the planets of Venus and Mars to Earth.
Venus is hot, VERY HOT 100s of degrees hot – Too much CO2 (greenhouse gasses)
Mars is a cold dry rock – lacks CO2 (greenhouse gasses)
14. What crisis did our planet face about 700 million years ago? What is its nickname?
The Earth was completely frozen over in what is nicknamed “Snowball Earth”.
15. What were the conditions like?
Temperatures were -50c, blizzards, whole planet frozen over.
16. How did volcanoes change the temperature of snow ball earth to help able to support life?
Volcanoes pumped out CO2 (carbon dioxide) and the green house gas helped to thaw Earth.
17. Where does Iain go to see some of the oldest fossils on earth? What were these early
complex life forms called and what were they like?
He goes to Australia to find Stromatolites. Very small multi celled creatures. Their remains fell
to the bottom of the ocean, along with plankton etc. provided carbon for CO2
18. Where does carbon dioxide come from and what role does it play in keeping earth fit to
sustain life? Remains of sea animals falls to the bottom of the ocean and then is pushed back
down into the magma through subduction. The CO2 released by volcanoes keeps Earth warm.
19. Describe the process of subduction.
When one tectonic plate is pushed down and under another tectonic plate.
20. What famous volcano is an example of a subduction volcano? Why is it famous?
Mt. St. Helens. It blew up violently in 1980 destroying everything for miles.
21. Describe the characteristic that volcanoes have that makes them so explosive and how that
characteristic is part of the regulation of the temperature of the planet?
CO2 gas builds up in subduction volcanoes, and sometimes the “throat” of the volcano can get
clogged up. Pressure builds up until it is released with explosive consequesnces.