Plate Tectonics

Front 1

True or False:
Earth's surface is constantly changing.

Back 1

True.

Front 2

True or False:
Earth looks different today from the way it did millions of years ago.

Back 2

True.

Front 3

where is the deepest mine in the world and what is the depth of it?

Back 3

a gold mine in South Africa. it reaches a depth of 3.8 kilometers.

Front 4

how far would you have to travel to reach Earth's center?

Back 4

over 6,000 kilometers.

Front 5

what are the two main types of evidence that geologists have used to learn about Earth's interior?

Back 5

1)direct evidence from rock samples
2)indirect evidence from seismic waves

Front 6

rocks from inside Earth give geologists clues about ________.

Back 6

Earth's structure.

Front 7

geologists have drilled holes as much as ____ kilometers into Earth.

Back 7

12.

Front 8

seismic waves-

Back 8

vibrations that travel through Earth carrying the energy released during an earthquake.

Front 9

the speed of seismic waves and the paths they take reveal __________.

Back 9

the structure of the planet.

Front 10

what prevents geologists from directly exploring Earth's interior?

Back 10

the extreme conditions in Earth's interior.

Front 11

how does the pressure change as you go from the surface toward the center of Earth?

Back 11

it increases.

Front 12

the three main layers that make up Earth are the _____, _____, and _____.

Back 12

crust, mantle, and core.

Front 13

crust-

Back 13

a layer of rock that forms Earth's outer skin.

Front 14

True or False:
the crust is thinnest under high mountains.

Back 14

false.

Front 15

the dark-colored rock that makes up most of the oceanic crust is _____.

Back 15

basalt.

Front 16

the light-colored rock that makes up most of the continental crust is _____.

Back 16

granite.

Front 17

lower mantle-

Back 17

solid material beneath the asthenosphere.

Front 18

lithosphere-

Back 18

rigid layer that includes the upper part of the mantle and the crust.

Front 19

asthenosphere-

Back 19

soft layer just below the lithosphere.

Front 20

True or False:
the asthenosphere is not considered solid because it can bend like plastic.

Back 20

false.

Front 21

True or False:
the mantle is nearly 3,000 kilometers thick.

Back 21

true.

Front 22

Earth's outer core contains _____ and _____.

Back 22

iron and nickel.

Front 23

Earth's inner core is ________.

Back 23

under extreme pressure.

Front 24

how does a compass needle align itself?

Back 24

with the lines of force in Earth's magnetic field.

Front 25

what creates Earth's magnetic field?

Back 25

the movements in the liquid outer core.

Front 26

what are three types of heat transfer?

Back 26

radiation, conduction, and convection.

Front 27

the movement of energy from a warmer object to a cooler object is called __________.

Back 27

heat transfer.

Front 28

radiation-

Back 28

the transfer of energy through space.

Front 29

what are two forms of radiation?

Back 29

sunlight and flame.

Front 30

conduction-

Back 30

heat transfer within a material or between materials that are touching.

Front 31

give an example of conduction:

Back 31

a spoon in a pot of soup heats up by conduction.

Front 32

convection-

Back 32

heat transfer by the movement of currents within a fluid.

Front 33

heat transfer by convection is caused by differences of ________ and density within a fluid.

Back 33

temperature.

Front 34

a measure of how much mass there is in a volume of a substance is ________.

Back 34

density.

Front 35

when a fluid's temperature increases, it's density ________.

Back 35

decreases.

Front 36

what three factors set convection currents in motion?

Back 36

heating and cooling of the fluid, changes in the fluid's density, and the force of gravity.

Front 37

what happens to convection currents when the liquid or gas is no longer heated?

Back 37

convection currents eventually stop.

Front 38

relationships among heat, movement, and density in mantle rock . . .

Back 38

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

Front 39

why is this relationship shown as a cycle?

Back 39

because the heating and cooling cycle appears over and over.

Front 40

where would mantle rock be the densest?

Back 40

after it cools.

Front 41

True or False:
the heat source for the convection currents in the mantle is the sun.

Back 41

false.

Front 42

where does the heat come from that drives this convection current in the mantle?

Back 42

from the core and mantle.

Front 43

a device that bounces sound waves off underwater objects is called _______.

Back 43

sonar.

Front 44

what is sonar used for?

Back 44

to find distance to an object.

Front 45

the process that continually adds new material to the ocean floor is called ___________.

Back 45

sea-floor spreading.

Front 46

in sea-floor spreading, where does new crust come from?

Back 46

molten material pushed up through the mid-ocean ridge.

Front 47

three types of evidence for sea-floor spreading:

Back 47

magnetic stripes, drilling samples, and evidence from molten material.

Front 48

a long, narrow and very deep canyon where the ocean floor bends down toward the mantle is called a _________________.

Back 48

deep-ocean trench.

Front 49

subduction-

Back 49

the process by which oceanic crust sinks beneath a deep-ocean trench and back into the mantle at a convergent plate boundary.

Front 50

what process in Earth's interior causes subduction and sea-floor spreading?

Back 50

convection currents.

Front 51

True or False:
the Pacific Ocean is shrinking.

Back 51

true.

Front 52

divergent-

Back 52

plates move apart at the mid ocean ridge due to new lava pushing up. (constructive boundries).

Front 53

convergent-

Back 53

when two plates come together at the trenches and are destroyed. (destructive boundries).

Front 54

transform-

Back 54

two plates slip past each other, moving opposite directions nothing created or destroyed. (strike-slip).

Front 55

True or False:
mid-ocean ridges were mapped using sonar.

Back 55

true.

Front 56

True or False:
the tops of some mid-ocean ridges are spilt by a steep-sided valley.

Back 56

true.

Front 57

how did drilling samples show that sea-floor spreading really has taken place?

Back 57

newer rock is closer to mid-ocean ridges, older rock is farther away.

Front 58

True or False:
at times in the past, a compass needle on Earth would have pointed south.

Back 58

true.

Front 59

what effect do subduction and sea-floor spreading have on Earth's surface?

Back 59

the size and shape of the ocean.

Front 60

True or False:
rock that makes up the ocean floor lies in a pattern of magnetized stripes.

Back 60

true.

Front 61

True or False:
at deep-ocean trenches, conduction allows oceanic crust to sink back into the mantle.

Back 61

false.

Front 62

why is the atlantic ocean expanding?

Back 62

sea-floor spreading and only a few short trenches in Atlantic.

Front 63

the lithosphere is broken into separate sections called ______.

Back 63

plates.

Front 64

True or False:
plates can carry continents or parts of the ocean floor but not both.

Back 64

false.

Front 65

what is a scientific theory?

Back 65

a well tested concept that explains a wide range of observations.

Front 66

True or False.
the theory of plate tectonics explains the formation, movement, and subduction of Earth's plates.

Back 66

true.

Front 67

plate boundary-

Back 67

line where the edges of Earth's plates meet.

Front 68

fault-

Back 68

break in Earth's crust where rocks have slipped past each other.

Front 69

rift valley-

Back 69

deep valley that forms where two plates pull apart.

Front 70

how are the movement of plates at divergent boundaries and at transform boundaries similar?

Back 70

both move horizontally.

Front 71

True or False:
crust is neither created nor destroyed along a transform boundary.

Back 71

true.

Front 72

most divergent boundaries occur along __________.

Back 72

mid-ocean ridges.

Front 73

when two plates converge, the result is called a ________.

Back 73

collision.

Front 74

when two plates collide, what determines which plate comes out on top?

Back 74

the density.

Front 75

True or False:
a continental plate sinks beneath an oceanic plate when the two plates collide.

Back 75

false.

Front 76

True or False:
where two plates meet, the one that is more dense sinks under the other.

Back 76

true.

Front 77

True or False:
valleys form where two plates carrying continental crust collide.

Back 77

false.

Front 78

was Pangaea the only supercontinent to have existed?

Back 78

no, because there might have been supercontinents or other formations before and after Pangaea.

Front 79

True or False:
the pieces of the supercontinent Pangaea began to drift apart about 225 million years ago.

Back 79

true.