Inside the Earth

The idea

Earth's layers — crust, upper mantle, lower mantle, outer core and inner core — increase in density towards the centre, as rising pressure and temperature make the materials heavier and more compact; the crust is lightest.

Digging down

The Earth is made of layers, from the crust to the centre.

What happens to the density as we go towards the centre?

• It increases
• It decreases
• It stays the same

Go to the centre

Press Next step.

Heavier inside

Each layer has its own range of density. Going deeper, both pressure and temperature rise significantly. This makes the materials heavier and more compact.

Earth's layers: crust, upper mantle, lower mantle, outer core, inner core. Density increases towards the centre. The crust is the lightest.

Notes

Density increases towards the centre of the Earth; the crust is lightest.

Check yourself

Which layer of the Earth is the lightest?

Going towards the centre of the Earth, the density …

Deeper inside the Earth, the pressure and temperature …

Which list is in the correct order, outermost to innermost?

• The inner core. The inner core is the densest.
• The crust — correct. Yes!
• The outer core. The crust is the outermost and lightest layer.
• decreases. It increases.
• stays the same. It increases.
• increases — correct. Yes!
• rise a lot — correct. Yes!
• fall. They rise significantly.
• stay the same. They rise significantly.
• Inner core, outer core, lower mantle, upper mantle, crust. That is innermost to outermost.
• Crust, upper mantle, lower mantle, outer core, inner core — correct. Yes!
• Crust, outer core, upper mantle, inner core, lower mantle. That is not the right order.