8.3.5 - Inside our Planet

Question 1

How far below the Earth’s surface is the Earth’s centre?

Answer 1

6370 km.

Question 2

Is the inner core liquid or solid?

Answer 2

Solid.

Question 3

Is the outer core liquid or solid?

Answer 3

Liquid.

Question 4

Is the mantle liquid or solid?

Answer 4

Solid but it can flow.

Question 5

Is the crust liquid or solid?

Answer 5

Solid, it is what we live on.

Question 6

What do earthquakes produce?

Answer 6

Seismic waves.

Question 7

How have scientists been detecting seismic waves since the 1850s?

Answer 7

Seismometers.

Question 8

What does a seismogram record?

Answer 8

The arrival and intensity of two types of seismic waves.

Question 9

What are the two types of waves that seismograms record?

Answer 9

1. P-waves.

2. S-waves.

Question 10

Where can you detect S-waves and P-waves?

Answer 10

Near the earthquakes centre.

Question 11

What are the zones called in which you cannot detect S-waves or P-waves, or neither?

Answer 11

Shadow zones.

Question 12

Which type of wave can travel through Earth?

Answer 12

P-waves.

Question 13

Which type of wave cannot travel through Earth?

Answer 13

S-waves.

Question 14

Why can P-waves travel through liquids and solids like sound?

Answer 14

They are longitudinal.

Question 15

Why can’t S-waves travel through liquids?

Answer 15

They are transverse.

Question 16

What about the structure of the Earth did Inge Lehmann work out by using P-waves?

Answer 16

That the centre of the Earth (inner core) is solid.