What is inside a volcano?

The inside of our planet is very hot. Deep down, some rock gets so hot that it melts into a thick, glowing liquid called magma.

Magma is lighter than the solid rock around it, so it slowly rises, a bit like a bubble in a bottle of fizzy drink.

A volcano is a place where this melted rock finds a way up through a crack in the ground. When it reaches the surface, it gets a new name: lava.

The lava cools and turns back into solid rock. Layer after layer, it builds up a mountain with a hole in the top, called a crater.

Some volcanoes bubble and ooze gently. Many sleep quietly for thousands of years. Scientists called volcanologists watch them closely, so people stay safe.

Whole islands, like Hawaii, were built by volcanoes, one layer of lava at a time.