Layers of the Earth

Question 1

Asthenosphere

Answer 1

Liquid, made of rock, convection currents, heated by the outer core through conduction. Convection currents cause the movement of tectonic plates.

Question 2

Crust

Answer 2

Top layer. Thinnest, coolest, made of rock. Part of lithosphere.

Question 3

Inner Core

Answer 3

Most inner layer. Most pressure, hottest, made of iron and nickel.

Question 4

Lithosphere

Answer 4

Most rigid, solid layer. It is the crust and the upper mantle, which Mr. Martin may refer to as the “top of mantle,” so be prepared for that.

Question 5

Mantle

Answer 5

Thickest layer. Top part and bottom part are solid, but the middle part is liquid-ish, at least enough for convection currents to happen. Made of rock and heated by outer core, which is heated by the inner core.

Question 6

Outer core

Answer 6

Only completely liquid layer, although it goes through a lot of pressure. Its flow over the inner core may cause Earth’s magnetic field.

Question 7

Oceanic Crust vs. Continental Crust

Answer 7

Oceanic Crust:

Basalt
More Dense
Younger
Thinner

Continental Crust:

Granite
Less Dense
Older
Thicker

Both:

Part of plates

Question 8

Convection currents in mantle - D to A

Answer 8

Heating

Question 9

A to B

Answer 9

Less dense, rock rises

Question 10

B

Answer 10

Heated rock, less dense

Question 11

B to C

Answer 11

Rock cooling, moving tectonic plates

Question 12

C

Answer 12

Cooled rock, density increases

Question 13

C to D

Answer 13

Sinking rock

Question 14

D

Answer 14

Cool, dense rock

Question 15

Law of superposition

Answer 15

Oldest layer on bottom, newest on top

Question 16

Index fossils

Answer 16

Fossils geologists and paleontologists use to find the relative age of rock layers. They must be widespread.

Question 17

How old is Earth?

Answer 17

4.54 byo. Around 4.6 billion years ago.

Question 18

Intrusive vs. Extrusive

Answer 18

Intrusive:

Molten material seeps through but does not emerge on top of the crust. It forms a new, younger rock layer among much older rock layers.

Extrusive:

Molten material emerges on top of the crust. It continues to form new, young rock layers on top of the crust.

Question 19

What happens when you go to the center of the earth?

Answer 19

As you go to the center of the Earth, temperature, density, and pressure increases.