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79 Cards in this Set
- Front
- Back
True or False:
Earth's surface is constantly changing. |
True.
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True or False:
Earth looks different today from the way it did millions of years ago. |
True.
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where is the deepest mine in the world and what is the depth of it?
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a gold mine in South Africa. it reaches a depth of 3.8 kilometers.
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how far would you have to travel to reach Earth's center?
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over 6,000 kilometers.
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what are the two main types of evidence that geologists have used to learn about Earth's interior?
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1)direct evidence from rock samples
2)indirect evidence from seismic waves |
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rocks from inside Earth give geologists clues about ________.
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Earth's structure.
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geologists have drilled holes as much as ____ kilometers into Earth.
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12.
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seismic waves-
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vibrations that travel through Earth carrying the energy released during an earthquake.
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the speed of seismic waves and the paths they take reveal __________.
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the structure of the planet.
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what prevents geologists from directly exploring Earth's interior?
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the extreme conditions in Earth's interior.
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how does the pressure change as you go from the surface toward the center of Earth?
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it increases.
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the three main layers that make up Earth are the _____, _____, and _____.
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crust, mantle, and core.
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crust-
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a layer of rock that forms Earth's outer skin.
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True or False:
the crust is thinnest under high mountains. |
false.
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the dark-colored rock that makes up most of the oceanic crust is _____.
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basalt.
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the light-colored rock that makes up most of the continental crust is _____.
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granite.
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lower mantle-
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solid material beneath the asthenosphere.
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lithosphere-
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rigid layer that includes the upper part of the mantle and the crust.
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asthenosphere-
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soft layer just below the lithosphere.
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True or False:
the asthenosphere is not considered solid because it can bend like plastic. |
false.
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True or False:
the mantle is nearly 3,000 kilometers thick. |
true.
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Earth's outer core contains _____ and _____.
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iron and nickel.
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Earth's inner core is ________.
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under extreme pressure.
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how does a compass needle align itself?
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with the lines of force in Earth's magnetic field.
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what creates Earth's magnetic field?
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the movements in the liquid outer core.
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what are three types of heat transfer?
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radiation, conduction, and convection.
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the movement of energy from a warmer object to a cooler object is called __________.
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heat transfer.
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radiation-
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the transfer of energy through space.
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what are two forms of radiation?
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sunlight and flame.
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conduction-
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heat transfer within a material or between materials that are touching.
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give an example of conduction:
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a spoon in a pot of soup heats up by conduction.
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convection-
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heat transfer by the movement of currents within a fluid.
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heat transfer by convection is caused by differences of ________ and density within a fluid.
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temperature.
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a measure of how much mass there is in a volume of a substance is ________.
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density.
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when a fluid's temperature increases, it's density ________.
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decreases.
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what three factors set convection currents in motion?
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heating and cooling of the fluid, changes in the fluid's density, and the force of gravity.
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what happens to convection currents when the liquid or gas is no longer heated?
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convection currents eventually stop.
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relationships among heat, movement, and density in mantle rock . . .
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mantle rock cools, particles move slower, particles occupy less space/density increases, mantle rock sinks back to the mantle, mantle rock is heated, particles move faster, particles occupy more space/density decreases, mantle rock rises
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why is this relationship shown as a cycle?
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because the heating and cooling cycle appears over and over.
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where would mantle rock be the densest?
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after it cools.
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True or False:
the heat source for the convection currents in the mantle is the sun. |
false.
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where does the heat come from that drives this convection current in the mantle?
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from the core and mantle.
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a device that bounces sound waves off underwater objects is called _______.
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sonar.
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what is sonar used for?
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to find distance to an object.
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the process that continually adds new material to the ocean floor is called ___________.
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sea-floor spreading.
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in sea-floor spreading, where does new crust come from?
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molten material pushed up through the mid-ocean ridge.
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three types of evidence for sea-floor spreading:
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magnetic stripes, drilling samples, and evidence from molten material.
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a long, narrow and very deep canyon where the ocean floor bends down toward the mantle is called a _________________.
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deep-ocean trench.
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subduction-
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the process by which oceanic crust sinks beneath a deep-ocean trench and back into the mantle at a convergent plate boundary.
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what process in Earth's interior causes subduction and sea-floor spreading?
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convection currents.
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True or False:
the Pacific Ocean is shrinking. |
true.
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divergent-
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plates move apart at the mid ocean ridge due to new lava pushing up. (constructive boundries).
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convergent-
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when two plates come together at the trenches and are destroyed. (destructive boundries).
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transform-
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two plates slip past each other, moving opposite directions nothing created or destroyed. (strike-slip).
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True or False:
mid-ocean ridges were mapped using sonar. |
true.
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True or False:
the tops of some mid-ocean ridges are spilt by a steep-sided valley. |
true.
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how did drilling samples show that sea-floor spreading really has taken place?
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newer rock is closer to mid-ocean ridges, older rock is farther away.
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True or False:
at times in the past, a compass needle on Earth would have pointed south. |
true.
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what effect do subduction and sea-floor spreading have on Earth's surface?
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the size and shape of the ocean.
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True or False:
rock that makes up the ocean floor lies in a pattern of magnetized stripes. |
true.
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True or False:
at deep-ocean trenches, conduction allows oceanic crust to sink back into the mantle. |
false.
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why is the atlantic ocean expanding?
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sea-floor spreading and only a few short trenches in Atlantic.
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the lithosphere is broken into separate sections called ______.
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plates.
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True or False:
plates can carry continents or parts of the ocean floor but not both. |
false.
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what is a scientific theory?
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a well tested concept that explains a wide range of observations.
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True or False.
the theory of plate tectonics explains the formation, movement, and subduction of Earth's plates. |
true.
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plate boundary-
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line where the edges of Earth's plates meet.
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fault-
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break in Earth's crust where rocks have slipped past each other.
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rift valley-
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deep valley that forms where two plates pull apart.
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how are the movement of plates at divergent boundaries and at transform boundaries similar?
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both move horizontally.
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True or False:
crust is neither created nor destroyed along a transform boundary. |
true.
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most divergent boundaries occur along __________.
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mid-ocean ridges.
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when two plates converge, the result is called a ________.
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collision.
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when two plates collide, what determines which plate comes out on top?
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the density.
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True or False:
a continental plate sinks beneath an oceanic plate when the two plates collide. |
false.
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True or False:
where two plates meet, the one that is more dense sinks under the other. |
true.
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True or False:
valleys form where two plates carrying continental crust collide. |
false.
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was Pangaea the only supercontinent to have existed?
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no, because there might have been supercontinents or other formations before and after Pangaea.
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True or False:
the pieces of the supercontinent Pangaea began to drift apart about 225 million years ago. |
true.
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