1.7 Earth's Structure

Question 1

State all the layers of the earth.

Answer 1

Crust (lithosphere)
Asthenosphere (upper mantle)
Lower mantle
Outer core
Inner core

Question 2

What is another name for the crust?

Answer 2

Lithosphere

Question 3

What are the properties of the lithosphere?

Answer 3

• The lithosphere is split into tectonic plates which move very slowly (2-5cm a year).
• The lithosphere is 5-70km thick.

Question 4

What are the properties of continental crust?

Answer 4

• It is 30-50 km thick.
• Not very dense.
• Mostly made of granite.

Question 5

What are the properties of oceanic crust?

Answer 5

• 6-8km thick.
• Light but dense.
• It is made of basalt.

Question 6

What are the properties of the asthenosphere?

Answer 6

• This is the top layer of the mantle
• It is slightly more solid than the lower mantle
• Temperature = 1000-3700 degrees celsius.

Question 7

What are the properties of the lower mantle?

Answer 7

• The mantle is the largest part of the earth’s layers
• It is semi-molten
• Temperature = 1000-3700 degrees celsius

Question 8

What are the properties of the outer core?

Answer 8

• This is the less dense layer of the core
• It is made up of iron and nickel - creates our magnetic field
• It is liquid

Question 9

What are the properties of the inner core?

Answer 9

• Very dense layer and it is solid because of the intense pressure.
• It is composed of iron and nickel-creating our magnetic field
• Temperature = 4400-6000 degree celsius

Question 10

Where do convection currents occur?

Answer 10

In the mantle

Question 11

What do convection currents move and how do they do it?

Answer 11

Convection currents move tectonic plates by radioactive decay causing the mantle to heat up and move in a circular motion.

Question 12

What is radioactive decay?

Answer 12

This is natural occurring radioactive chemicals such as uranium or thorium

Question 13

What is residual heat?

Answer 13

This is the heat leftover from the earth’s formation.