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79 Cards in this Set

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