KS3 Science · Earth structure

Inside the Earth, and how igneous rocks form

Explore the layers beneath your feet, then watch how cooling speed decides whether a rock ends up with big crystals or small ones.

The three layers

Tap a layer on the diagram — or step through them in order. The crust really is this thin compared with what’s below it.

CORE MANTLE CRUST

Diagram not to scale — the crust is far thinner in reality.

Pick a layer to reveal what it’s made of.

How igneous rocks form

Igneous rock — rock formed from cooling magma or lava. The big question: how fast did it cool? That decides the crystal size.

Magma · underground 1150 °C

Choose where it cools, then press “Cool the rock” and watch the crystals grow.