The Structure of the Earth
Science: KS3, topic 2.5.2
The Structure of the Earth
There are four layers of the Earth.
The crust
- The outermost layer of the Earth is the crust.
- This is the section we stand on.
- It is made of rock and so is a solid.
- The thickness of the crust ranges from around 6km to 40km.
- It is less thick at the bottom of the oceans.
- The crust is broken into different pieces which we call tectonic plates.
The mantle
- The mantle is the thickest section of the Earth.
- The mantle is nearly 3000 km thick.
- It is made of molten rock.
- This solid rock has unusual properties as the molten rock can flow.
- It can flow as the heat from Earth’s core produces convection currents.
- Convection currents move the tectonic plates which may lead to Earthquakes.
Outer core
- The Outer Core is a liquid.
- It is made of iron and nickel.
- The Outer Core is responsible for and drives the Earth’s magnetic field.
Inner core
- The inner core is solid.
- Like the outer core, it is made of iron and nickel.
- In recent years, scientists have come to think that silicon makes up part of the inner core.
- It is thought temperatures in the inner core are around 6000°C. This is about as hot as the surface of the sun.
Test yourself on The Structure of the Earth
The Earth's inner core reaches about 6000°C. Which object has a surface at about the same temperature?
Why can the solid rock in the Earth's mantle flow?
How does the thickness of the mantle compare with the thickness of the crust?