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11 Cards in this Set
- Front
- Back
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Define earth's crust.
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earth's outermost layer of rock
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Define sediment.
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small, solid fragments of rock and other materials that are carried and deposited by wind, water, or ice. Examples would be sand, mud, or gravel.
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Define sedimentary rock.
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rock formed when chemical reactions cement sediments together, hardening them
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Define igneous rock.
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rock that forms from molten rock
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Define metamorphic rock.
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igneous or sedimentary rock that has been changed into a new kind of rock as a result of great pressure and temperature
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Consider the three types of rock mentioned in the second section. Which one would be more likely to be found deep in the crust?
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Metamorphic rock is more likely to be found deep in the crust. Remember, metamorphic rock forms because of great pressure. The deeper the rock is in the crust, the more weight presses down on it, so the more pressure it experiences. There are other ways to get a high pressure situation, however, so metamorphic rock does not have to be deep in the crust.
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Define plastic rock.
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rock that behaves like something between a liquid and a solid
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Suppose you had a long, steel rod, and you stood at one end of it while a friend stood at the other end. Consider the following experiment: Your friend hit his end of the rod with a hammer, and you listen for the sound. You then press an ear against the rod, and your friend hits it with the hammer again. In which case would the sound be louder? NOTE: Please don't try this at home!
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The sound would be louder when you put your ear to the rod. Experiment 6.1 showed that sound travels better through a solid (the string) than through air. Since steel is solid, sound will travel better through it.
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Suppose you were able to remove a sample of the plastic rock from the asthenosphere and take it into a laboratory. Would it behave differently than a rock sample you took from earth's crust? Why or why not?
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It would not behave differently than any other rock. Remember, the plastic nature of the rock in the mantle is due to the extreme heat and pressure found there. As soon as you remove the rock from the mantle and take it to the lab, that heat and pressure are gone. It will then behave just like any other rock.
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Would water be subject to pressure freezing? Why or why not?
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No, it would not. Water is one of the few substances in creation that has its molecules closer when it is a liquid compared to when it is a solid. Thus, if I press water molecules closer together they become more liquid. In fact, if you exert pressure on ice it will melt, because you are pushing the molecules closer together, like they are in liquid water. Please note that at extreme pressures, water can become a solid, but that solid is not what you and I would call “ice.”
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Regardless of whether the dynamo theory, the rapid-decay theory, or some as yet unknown theory is correct in explaining the earth's magnetic field, we are reasonably certain that substances in the core of the earth are in motion. Why?
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The earth has a magnetic field that must be caused by the motion of electricity. Thus, something in the core must be moving, or there would be no electrical flow and thus no magnetic field.
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