PUT YOUR HANDS IN THE AIR FOR THE LAYERS OF THE EARTH
(only need to know 'core' not the inner and outer bits)
Describe the basic shape and structure of the Earth
1. Almost spherical
2. Has a layered structure
Describe the crust
1. Very thin (5-50km)
2. Surrounded by the atmosphere
Describe the mantle
1. Below crust
2. Has all the properties of a solid except that it can flow very slowly
What happens within the mantle?
What does this do?
Produces lots of heat, which causes the mantle to flow in convection currents
Describe the core
1. At the centre of the Earth
2. Made of iron and nickle (we think)
Which 2 metals do we think the core is made of?
Iron and nickle
Define 'tectonic plates'
The large pieces that the crust and upper-mantle are cracked into
What causes the tectonic plates to drift?
The convection currents in the mantel
What speed are most plates moving at?
A few cm per year
(relative to each other)
What causes an earthquake?
The tectonic plates moving very suddenly
Where do earthquakes and volcanoes often occur?
At the boundaries between two tectonic plates
Can scientists predict when earthquakes and volcanic eruptions will occur?
No - it is impossible to predict when tectonic plates will move
Give an example of a 'clue' that scientists are looking for in order to predict when tectonic movement is likely to happen
Strain in underground rocks
Name a flaw with using clues to predict sudden tectonic movement
They will only be able to predict when an earthquake is likely to happen, not the exact time
Name a clue that could indicate an imminent volcanic eruption
Before an erruption, molten rock rises up into the chambers near the surface, causing the ground surface to bulge slightly.
This causes mini-earthquakes near the volcano
Name a flaw with using mini-earthquakes near a volcano to predict eruptions
Sometimes molten rock cools down instead of erupting, so mini-earthquakes can be a false alarm