1: The structure of the Earth

Question 1

What is the structure of the Earth?

Answer 1

• the crust which is rocky and thin compared with the other layers
• the mantle
• the outer core (liquid)
• the inner core (solid) which contains iron and is very hot

Question 2

What is the lithosphere?

Answer 2

the crust and the outer part of the mantle

Question 3

What are tectonic plates?

Answer 3

large pieces of the Earth’s crust that gradually move across the surface of the mantle

Question 4

Why do tectonic plates float above the mantle?

Answer 4

they are less dense than the mantle

Question 5

Why do earthquakes occur?

Answer 5

due to movement of the tectonic plates

friction and seismic waves

Question 6

Why do volcanoes occur?

Answer 6

between plate boundaries (where the plates meet)
molten rock or magma get to the surface through weak areas in the crust.
magma can rise through the crust because it is less dense than the crust.

Question 7

What happens at a destructive plate boundary (oceanic and continental colliding)?

Answer 7

`Convection currents in the mantle push the tectonic plates around.
The oceanic plate is denser so subducts under the continental plate.
The subducted oceanic plate partially melts due to high temps in the mantle and magma rises up to the continental plate causing volcanoes.