Chapter 3: Forces that Cause Earth Movements

Question 1

What causes convection to occur?

Answer 1

Convection is caused by heating from below and cooling from above.

Question 2

When heated liquid reaches what, it shrinks?

Answer 2

When heated liquid reaches cool surroundings, it shrinks.

Question 3

When rocks are heated what happens?

Answer 3

Rocks expand when they are heated.

Question 4

What is the lithosphere also called?

Answer 4

The lithosphere is also called the rock sphere.

Question 5

All the Earth’s oceans have a continuous what that is called a mid-ocean ridge?

Answer 5

All the Earth’s oceans have a continuous mountain range called a mid-ocean ridge.

Question 6

When magma solidifies at the surface of a mid-ocean ridge it is called what?

Answer 6

When magma solidifies at the surface of a mid-ocean ridge it is called basalt.

Question 7

Basalt forms new what in the oceans?

Answer 7

Basalt forms new crust in the oceans.

Question 8

What is the movement of new oceanic crust away from the ridge and old oceanic crust being recycled in the trenches?

Answer 8

Seafloor spreading is the movement of new oceanic crust away from the ridge and old oceanic crust being recycled in the trenches.

Question 9

What happens when magma is less dense than the surrounding rocks along the mid-ocean ridge?

Answer 9

When magma is less dense than the surrounding rocks, it rises up to form volcanoes along the mid-ocean ridge.

Question 10

(Think about temperature) The outermost part of the Earth (crust) is what than the deeper layers of the Earth?

Answer 10

The outermost part of the Earth (crust) is cooler than the deeper layers of the Earth.

Question 11

What is naturally occurring molten rock material generated within the Earth?

Answer 11

Magma is naturally occurring molten rock material generated within the Earth.

Question 12

What is the rigid, outer portion of the Earth?

Answer 12

The rigid, outer portion of the Earth is the lithosphere.

Question 13

What is the density driven movement of a fluid material?

Answer 13

Convection is the density driven movement of a fluid material

Question 14

A vent in the surface of the Earth through which magma, gases, and ash erupt is what?

Answer 14

A vent in the surface of the Earth through which magma, gases, and ash erupt is a volcano.

Question 15

What is located immediately below the lithosphere?

Answer 15

The asthenosphere is located immediately below the lithosphere.

Question 16

Something’s mass per unit volume is its what?

Answer 16

Something’s mass per unit volume is its density.

Question 17

Name the five differences between the asthenosphere and the lithosphere.

Answer 17

1) Asthenosphere- Acts like a liquid, Lithosphere- Acts like a solid.
2) Asthenosphere- Convects, Lithosphere- Does not convect.
3) Asthenosphere- Very hot, Lithosphere- Cool.
4) Asthenosphere- Thicker, Lithosphere- Thinner.
5) Asthenosphere- One layer (lower mantle), Lithosphere- Two layers (crust and upper mantle).

Question 18

What happens in the asthenosphere?

Answer 18

Convection happens in the asthenosphere.

Question 19

What is seafloor spreading?

Answer 19

Seafloor spreading is when magma rises and cools at the mid-ocean ridge to form new crust, and the spreading apart of the seafloor to bring old crust to the trenches to be recycled into magma that will become new crust.

Question 20

What force is making the seafloor spread apart in this picture (picture of seafloor spreading)?

Answer 20

Convection cells and gravity are making the seafloor spread apart.

Question 21

The process of when old crust goes through a trench and becomes magma that will cool into new crust is what?

Answer 21

The process is called seafloor spreading.

Question 22

How is basalt formed?

Answer 22

Basalt is formed by magma cooling at the mid-ocean ridge.

Question 23

If you could make magma, what would you have to do?

Answer 23

To make magma you would have to melt rock.

Question 24

Why is the lithosphere nicknamed the “rock sphere?”

Answer 24

The lithosphere is nicknamed the “rock sphere” because it’s rigid solid rock that doesn’t convect.

Question 25

Where is the crust the oldest?

Answer 25

The crust is the oldest when it is the furthest away from the mid-ocean ridge at the trenches.

Question 26

How can the mantle convect if it is a solid?

Answer 26

The mantle can convect if it is a solid because it gets melted by the core and there is extreme pressure from the surrounding layers.

Question 27

What is the typical speed of mantle convection?

Answer 27

The typical speed of mantle convection is about as fast as fingernails grow or a few centimeters per year.

Question 28

What is the reason for volcanic activity along mid-ocean ridges?

Answer 28

The reason for volcanic activity along mid-ocean ridges is because the rocks expand when they are heated and the hot mantle rock rises up and the less dense magma rises up to form volcanoes along the ridge.

Question 29

Is the rock that makes up the mid-ocean ridge young or old?

Answer 29

The rock that makes up the mid-ocean ridge is young because new crust comes out of the mid-ocean ridge and old crust goes into the trenches.

Question 30

How does convection in the Earth's mantle help shape the geosphere?

Answer 30

Convection in the Earth's mantle help shape the geosphere by making the new crust, making the lithospheric plates move, and new crust is also formed and old crust is recycled.

Question 31

What is the asthenosphere?

Answer 31

The asthenosphere is a region of the Earth's interior immediately below the lithosphere where mantle rocks are hot enough and under enough pressure to deform, change shape and flow.

Question 32

What is a volcano?

Answer 32

A volcano is a vent in the surface of the Earth through which magma and associated gases and ash erupt.

Question 33

What is the lithosphere?

Answer 33

The lithosphere is a term used in plate tectonics that refers to the rigid outer portion of the Earth. The lithosphere is composed of the crust and the uppermost portion of the mantle.

Question 34

What is a convection cell?

Answer 34

A convection cell is a pattern of fluid movement where at one side material rises, moves laterally, then eventually sinks again to return back to its starting point.

Question 35

What does density mean?

Answer 35

Density means mass per unit volume.

Question 36

What is magma?

Answer 36

Magma is naturally occurring molten rock material, generated within the Earth from which igneous rocks are derived through solidification and related processes.

Question 37

What is the mid-ocean ridge?

Answer 37

The mid-ocean ridge is a continuous median mountain ridge extending through an ocean, which is seismically active and often has a central rift valley and rugged topography. Mid-oceanic ridges are divergent plate boundaries and are the site of sea-floor spreading and the formation of new oceanic crust.

Question 38

What is convection?

Answer 38

Convection is the density-driven movement of a fluid material. Often, convection is driven by either heating from below or cooling from above the fluid.