Structure of the Earth

Question 1

True or False: the earth’s crust is approx 12km deep

Answer 1

False: it is about 20km deep (the deepest anyone has drilled into the crust is 12km)

Question 2

True or false: the mantle is the layer beneath the crust

Answer 2

True

Question 3

what is the earth’s mantle made up of

Answer 3

rock and molten rock called magma

Question 4

True or false: the earth’s inner core is comprised of liquid iron and nickel

Answer 4

false: the inner core is made of solid iron and nickel

Question 5

what is the name given to rock that originated from erupting volcanoes?

Answer 5

igneous rock

Question 6

draw a diagram of the earth and label the 4 main parts of its structure

Answer 6

inner to outer: inner core, outer core, mantle, crust

Question 7

true or false: the diameter of the earth is approx 6300km

Answer 7

false: diameter is approx 12 700km (distance from earth’s centre to its surface is about 6371km)

Question 8

comment on the structure and properties of the earth’s core (5 marks)

Answer 8

• made up of outer and inner core
• outer core made of liquid iron and nickel
• inner core is solid due to massive pressure exerted on it
• inner core made of solid iron and nickel
• temps in the core approx 5000 to 6000 degrees C

Question 9

what is the difference between oceanic and continental crust

Answer 9

oceanic crust is found under the oceans and is the thinnest part of the earth’s crust (about 10km thick)
continental crust is thicker (up to 35km thick) and forms the continents

Question 10

what causes the movements of tectonic plates

Answer 10

Immense heat from the earth’s core heats magma in the earth’s mantle. Heated magma rises causing convection currents in the magma. These currents move the plates

Question 11

what are tectonic plates

Answer 11

the earth’s crust is broken up into sections called plates

Question 12

how fast do tectonic plates move

Answer 12

1 to 10cm per year

Question 13

when convection currents in the magma diverge near the earth’s crust, then plates move towards each other OR apart from each other?

Answer 13

apart

Question 14

what is a plate boundary

Answer 14

the line along which 2 plates meet

Question 15

define convergent movement and what can happen as a result

Answer 15

when plates move towards one another
2 things can happen:
1) one plate can be pushed under the other (volcanoes are then likely as molten material from the sinking late rises to the surface)
2) the 2 plates can meet and lift forming a mountain range (such as the Himalayas)

Question 16

how are ocean ridges formed

Answer 16

when plates diverge and magma rises to the crust under the oceans

Question 17

what is transform movement

Answer 17

when plates move past each other

Question 18

where is the Nazca plate found

Answer 18

off the wets coast of South America in the Pacific Ocean

Question 19

define plate tectonics

Answer 19

the movement of the earth’s plates and the activity insde the earth