Science Study Guide Chapter 5

What are convection currents and what causes them?

A convection current is the flow that transfers heat within a fluid and is caused by the heating and cooling of the fluid, the changes in the fluids density, and the force of gravity.

How does the temperature change as you go from the surface toward the center of Earth?

At the surface, the surrounding rock is cool, then the temperature increases slowly, but steadily.

______ is heat transfer by direct contact of particles of matter.

Conduction

Explain what force caused the movement of the continents from one supercontinent to their present positions.

Convection currents in the mantle is the force that caused the movement of the plates that carry the continents.

Name all the layers of the Earth, in order.

Crust, Mantle, Outer Core, Inner Core

What causes convection currents in Earth's mantle?

Heat from the core and the mantle itself causes convection currents in the mantle.

What is conduction?

Heat transfer within a material or between materials that are touching

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 old oceanic crust as new molten material rises from the mantle?

Older rock moves outward on both sides of the mid ocean ridge.

State the theory of plate tectonics.

Pieces of Earth's lithosphere are in slow constant motion driven by convection currents in the mantle.

What is sonar used for?

Sonar is used to determine the distance to an object.

What are two forms of radiation?

Sunlight and the heat you feel around a flame or open fire.

Why is the Atlantic Ocean expanding?

The Atlantic Ocean has only a few short trenches. The spreading ocean floor has nowhere to go.

Compare and contrast the asthenosphere with the lithosphere.

The asthenosphere and lithosphere are both part of the mantle, however, the asthenosphere is the soft layer and is bendable just below the lithosphere and the lithosphere is the rigid layer that includes the upper part of the mantle and the crust.

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

The deeper you go, the greater the pressure

What prevents geologists from directly exploring Earth's interior?

The extreme conditions of the heat and pressure of the Earth's interior.

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

The farther away from the ridge the samples are taken the older the rock. the newest rock is always in the center of the ridges.

Was Pangaea the only supercontinent to have existed? Explain your answer.

The movement of Earth's plates has greatly changed Earth's surface. Geologists have evidence that, before Pangaea existed, other supercontinents formed and split apart over billions of years.

What creates Earth's magnetic field?

The movements in the liquid outer core

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

The plate that is less dense.

What is radiation?

The transfer of energy through space by waves

What are two types of evidence geologists use to learn about Earth's interior?

The two types of evidence that geologist use to learn about the Earth's interior are direct evidence from rock samples and indirect evidence from seismic waves.

Describe how a compass needle aligns itself.

With the Earth's magnetic fields

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

Without heat, convection currents eventually stop.

What is an example of conduction?

a spoon in a pot of soup heats up by conduction because the heat from soup transfers to the spoon

name the letter of each sentence that is true about Earth's magnetism. a. At times in the past, a compass needle on Earth would have pointed south. b. Rock that makes up the ocean floor lies in a pattern of magnetized stripes. c. The pattern of stripes is different on both sides of mid-ocean ridges. d. The magnetic memory of rock on the ocean floor changes over time.

a. and b.

name the letter of each sentence that is true about mid-ocean ridges. a. The mid-ocean ridges were mapped using sonar. b. The mid-ocean ridges are found only below the Pacific Ocean. c. The mid-ocean ridges are completely under water. d. The tops of some mid-ocean ridges are split by a steep-sided valley.

a. and d.

Soft layer just below the lithosphere is the ___________.

asthenosphere

soft layer of rock in the mantle

asthenosphere

Circle the letter of the sentence that describes what happens to a fluid when its temperature increases. a. Its particles occupy less space. b. Its density decreases. c. Its particles move more slowly. d. Its particles settle together more closely.

b.

Name letter of each sentence that is true about Earth. a. Indirect evidence of Earth's interior comes from studying rock samples. b. Geologists cannot observe Earth's interior directly. c. It is over 6,000 kilometers from the surface to the center of Earth. d. Geologists learn about Earth's interior by drilling holes.

b. and c.

name the letter of each sentence that is true about convergent boundaries. a. Where two plates carrying oceanic crust meet, subduction does not take place. b. An oceanic plate sinks beneath a continental plate when the two plates collide. c. Where two plates meet, the one that is more dense sinks under the other. d. Mountain ranges form where two plates carrying continental crust collide.

b., c., and d.

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

basalt

a rock that makes up much of the ocean floor

basalt

Name letter of each sentence that is true about Earth's outer core. a. It is under low pressure. b. It is made of solid metal. c. It contains iron and nickel. d. It is a solid.

c.

When two plates converge, the result is called a(n) _________________.

collision

________ is the transfer of heat by the movement of a heated fluid.

convection

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

convection currents

means to come together toward one point

converge

___________ is 2 plates coming together.

convergent boundary

where two plates come together

convergent boundary

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

crust

outer rind of rock

crust

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

crust, mantle, and core

Name the letter of each sentence that is true about Earth's inner core. a. It consists of molten metal. b. It is a thick liquid. c. It is not very dense. d. It is under extreme pressure.

d.

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

deep ocean trench

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

density

means to move in different directions from a common point

diverge

The place where two plates move apart along the mid-ocean ridges where sea-floor spreading occurs.

divergent boundary

is when 2 plates move apart from from one common point

divergent boundary

Is the following sentence true or false? Earth looks the same today as it did millions of years ago.

false

Is the following sentence true or false? Plates can carry continents or parts of the ocean floor but not both.

false

Is the following sentence true or false? The asthenosphere is not considered solid because it can bend like plastic.

false

Is the following sentence true or false? The crust is thinnest under high mountains.

false

Is the following sentence true or false? The heat source for the convection currents in the mantle is the sun.

false, outer core

Is the following sentence true or false? At deep-ocean trenches, conduction allows oceanic crust to sink back into the mantle.

false, subduction

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

fault

breaks in Earth's crust where rocks have slipped past each other—form along these boundaries

fault

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

granite

a rock that makes up the core of the continents

granite

The movement of energy from a warmer object to a cooler object is called _______.

heat transfer

The movement of energy from a warmer object to a cooler object is called _________________.

heat transfer

Rigid layer that includes the upper part of the mantle and the crust is the __________.

lithosphere

the uppermost part of the mantle

lithosphere

Solid material beneath the asthenosphere is the ________.

lower mantle

Density is a measure of how much _______ there is in a volume of a substance.

mass

Most divergent boundaries occur along ___________________________.

mid ocean ridge

A chain of underwater mountains along which sea-floor spreading occurs is a _________________.

mid-ocean ridge

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

molten material that erupts and cools.

List three types of evidence for sea-floor spreading.

molten material, magnetic stripes, and the ages of the rocks themselves from drilling samples of rocks

the layer made up of liquid iron and nickel

outer core

Line where the edges of Earth's plates meet

plate boundary

pieces of Earth's lithosphere are in slow, constant motion, driven by convection currents in the mantle.

plate tectonics

The lithosphere is broken into separate sections called _________________.

plates

The separate sections or cracks in the lithosphere are called _______.

plates

the force pushing on a surface or area

pressure

The transfer of energy through empty space is called _______.

radiation

List the three types of heat transfer.

radiation, conduction, convection

A deep valley that forms along divergent boundaries.

rift valley

Deep valley that forms where two plates pull apart

rift valley

Geologists use direct evidence from __________ to learn about Earth's interior.

rock samples

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

scientific theory

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

sea floor spreading

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

sea floor spreading

_________________ waves are produced by earthquakes.

seismic

a wave produced by an earthquake

seismic wave

Geologists learn about Earth's interior using indirect evidence from ________________.

seismic waves

A device that bounces sound waves off underwater objects is called _________________.

sonar

A device that scientists use to map the ocean floor is _________________.

sonar

Seismic waves reveal the structure of Earth through their ________________ and ________________.

speed and paths

The process by which the ocean floor sinks into the mantle is called _________________.

subduction

convection currents in the Earth's mantle causes __________.

subduction

What is subduction?

subduction is the process by which ocean floor sinks beneath a deep ocean trench and back into the mantle.

Heat transfer by convection is caused by differences of_______________ and density within a fluid.

temperature

sea floor spreading results in _______________________________________________.

the change of size and shape of the ocean

what happens when oceanic crust collides with a plate carrying continental crust?

the denser oceanic crust is subducted

what happens when two plates carrying oceanic crust collide?

the denser plate sinks below the other one at deep ocean trench

What is convection?

the movement of currents within a fluid

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

they both move horizontal

what happens when two plates carrying continental crust collide?

they squeeze together to form a mountain range

means to change form or appearance

transform

_________ is when 2 plates slip past each other.

transform boundary

is a place where two plates slip past each other, moving in opposite directions.

transform boundary

Is the following sentence true or false? Crust is neither created nor destroyed along a transform boundary.

true

Is the following sentence true or false? The mantle is nearly 3,000 kilometers thick.

true

Is the following sentence true or false? The pieces of the supercontinent Pangaea began to drift apart about 225 million years ago.

true

Is the following sentence true or false? The theory of plate tectonics explains the formation, movement, and subduction of Earth's plates.

true

Is the following statement true or false? The Pacific Ocean is shrinking.

true