Hazards: 5.2 The Structure of the Earth

Question 1

Define Magma

Answer 1

Molten Rock (or lava at surface)

Question 2

Define Igneous Rock

Answer 2

Rocks formed by the cooling of molten magma (intrusive or extrusive)

Question 3

Define Intrusive

Answer 3

Magma that cools slowly before the surface (forms coarse-grained igneous rock e.g; granite)

Question 4

Define Extrusive

Answer 4

Lava in contact with the air or sea

Question 5

Define Sima

Answer 5

Oceanic crust made of mainly basalt (made of silica and magnesium)

Question 6

Define Sial

Answer 6

Continental Crust made of mainly granite rocks (made of silica and aluminium)

Question 7

Define Lithosphere

Answer 7

Crust and upper mantle - tectonic plate location

Question 8

Define Asthenosphere

Answer 8

Solid layer just below lithosphere

Question 9

Outline the 2 types of crust in the Earth

Answer 9

Oceanic Crust - made of sima - younger and thinner
Continental Crust - made of sial - older and thicker

Question 10

Outline the length of the Mantle

Answer 10

2,900 km thick - widest section

Question 11

Outline the state of the Mantle

Answer 11

Great heat and pressure = silicate rocks are a thick liquid that’s denser a you get deeper

Question 12

Outline the state of rocks in the Upper Mantle

Answer 12

Solid on top of asthenosphere - plastic like

Question 13

What does the Asthenosphere do to the lithosphere

Answer 13

Carries it on top of it as it moves slowly

Question 14

Outline the temperature in the Core

Answer 14

Hottest part of the Earth - can be 5000 degrees celsius

Question 15

Outline the composition of the Core

Answer 15

Outer Core - semi-liquid, mainly iron
Inner-Core - solid, iron-nickel alloy

Question 16

Outline how the Earth has a magnetic field

Answer 16

As the Earth spins + the liquid outer core spins = Magnetic Field