RE - Structure of the earth

Question 1

The earth consists if four concentric layers. What are they?

Answer 1

• Inner core
• Outer core
• Mantle
• Crust

Question 2

Describe the inner core

Answer 2

• Located at the centre of the Earth
• Hottest part of the Earth
• It is solid and made up of iron and nickel
• Reaches temperatures of up to 5,500°C

Question 3

Describe the outer core

Answer 3

• Layer surrounding the inner core
• It is a liquid layer, also made up of iron and nickel.
• It is still extremely hot, with temperatures similar to the inner core.

Question 4

Describe the mantle

Answer 4

• Widest section of the Earth
• It has a thickness of approximately 2,900 km.
• Made up of semi-molten rock called magma - In the upper parts of the mantle the rock is hard, but lower down the rock is soft and beginning to melt.

Question 5

Describe the crust

Answer 5

• Outer layer of the earth
• It is a thin layer between 0-60 km thick
• The crust is the solid rock layer upon which we live.

Question 6

What is the crust made up of?

Answer 6

Tectonics plates that are constantly moving

Question 7

What are the two different types of plates?

Answer 7

Continental - which carries land

Oceanic - which carries water

Question 8

Give some facts about Oceanic crust

Answer 8

• Newer - more or less than 200 million years old
• Denser
• Can sink
• Can be renewed and destroyed

Question 9

Give some facts about Continental crust?

Answer 9

• Older - most over 1500 million years old
• Less dense
• Cannot sink
• Cannot be renewed or destroyed

Question 10

What are convection currents?

Answer 10

The circular movement of heat in the mantle generated by radioactive decay in the core

Question 11

What do convection currents cause?

Answer 11

Plate movements (plate tectonics)

Question 14

What do plate tectonics cause?

Answer 14

Earthquakes and volcanos

Question 15

Where do two plates meet? (This is where volcanos and earthquakes are most likely to occur)

Answer 15

Plate boundary

Question 16

What are the three plate boundaries and what happens to the plates?

Answer 16

• Constructive/divergent/tensional boundary the plates move apart.
• Destructive/compressional/convergent boundary the plates move towards each other
• Conservative/ transform boundary the plates slide past each other.

Question 17

Describe in more detail what happens at destructive plate margins wit the ocean and continental plates

Answer 17

Convection currents cause plates to move together. Denser oceanic crust sinks under the lighter continental crust in a process called subduction. Pressure is exerted on oceanic crust and it is destroyed and mets into magma

Question 18

Describe what happens at destructive plate margins with two continental plates

Answer 18

If they meet each other, they collide rather than one sinking beneath the other.

Question 19

Describe in more detail what happens at constructive plate margin

Answer 19

When oceanic plates move apart from each, cracks form between the plates where there is no crust. Magma forces it way through the cracks and the surface forming a volcano. New land is formed as the plates pull away

Question 20

Describe in more detail what happens at conservative plate margin

Answer 20

Plates slide past each other moving in the same direction but at different angles and speeds. As one plate is moving slight faster than the other, it causes them to get stuck. This builds up pressure and eventually it is releases causing an earthquake. Crust is neither destroyed or made