Lecture 10

Question 1

What are the layers of the Earth?

Answer 1

• core
• mantle
• crust
  -lithosphere

Question 2

What is density?

Answer 2

-mass/volume
-M/(4/3)pi*r^3 (for a sphere)

Question 3

What is the Earth’s core?

Answer 3

Highest density. Contains nickel and iron

Question 4

What is the Earth’s mantle?

Answer 4

Moderate density. Contains silicon, oxygen etc

Question 5

What is the Earth’s crust?

Answer 5

Lowest density. Contains granite, basalt etc

Question 6

What is differentiation?

Answer 6

• Gravity pulls high-density material to the centre
• Lower-density material rises to the surface
• Material ends up separated by density

Question 7

What is the lithosphere?

Answer 7

The planet’s outer surface- rigid part of the crust and upper layer of the mantle.

Cool, rigid rock that behaves with elasticity over time. It floats on the warmer, softer rock underneath.

Question 8

What are the types of seismic waves?

Answer 8

P waves- longitudinal waves
S waves- transverse waves

Question 9

Which of the waves travel through Earth’s core?

Answer 9

P waves

Question 10

Why is the Earth’s core hot?

Answer 10

Accretion and differentiation was the initial reason- however, this energy was lost over time.

Radioactive decay is the main source of the core’s heat today

Question 11

How does the interior of the planet cool?

Answer 11

-Convection- transports heat as hot material rises and cool material falls

-Conduction- transfers heat from hot material to cool material

-Radiation- sends energy into space

Question 12

How does surface area to volume ration affect the cooling of large planets?

Answer 12

Larger objects have a smaller ratio and cool slower

Question 13

What are the sources of magnetic fields?

Answer 13

Magnetic fields are created by motions of charged particles

Question 14

What are the three requirements for Earth’s magnetic field?

Answer 14

• molten, electrically conducting interior
• convection
• moderately rapid rotation

Question 15

How can the magnetic poles move?

Answer 15

Subduction of the crust material can change the polarity of the magnetic field

Question 16

What are the four main processes for shape surfaces?

Answer 16

• Impact cratering
• Volcanism
• Tectonics
• Erosion

Question 17

What are some key features of impact cratering?

Answer 17

• mainly occurred after the creation of the solar system
• craters are about 10 times wider than the objects that made them
• there are more smaller craters than large ones

Question 18

What is volcanism?

Answer 18

• volcanism occurs when molten rock passes from the lithosphere to the surface
• molten rock=lava at the surface

Question 19

What are the three types of lava and their effects?

Answer 19

1. runny lava=flat lava plains
2. thicker lava=broad shield volcanoes
3. thickest lava=stratovolcanoes

Question 20

What is outgassing

Answer 20

When gasses are released from volcanoes

Question 21

What is tectonics? And what are the effects of tectonic movement?

Answer 21

• convection of the mantle creates stresses in the crust called tectonic forces
• compression of crust creates mountain ranges
• valleys form where the crust pulls apart

Question 22

What is erosion?

Answer 22

Weather driven processes that break down/transport rock

Question 23

What are agents that cause erosion?

Answer 23

-glaciers
-rivers
-wind
-rain

Question 24

What are the three types of craters?

Answer 24

-Standard: bowl shape, sharp rim, ring of ejected debris
-Impact into icy ground: unusual ridges caused by muddy impact debris
-Eroded craters: misshaped due to erosion by rain