What makes a volcano erupt?
A plain-English answer for grown-ups of kids aged 6–9, taken from the Yufena lesson that explores this question.
This is a members' lesson. Four other lessons are free to try.
The answer, for parents
Short answer: Gas bubbles in hot magma build up pressure until the volcano erupts.
Deep under the ground, it is very, very hot. It is so hot that rock melts! Melted rock under the ground is called magma. The Earth's outer shell is cracked into giant pieces. These pieces are called plates. Indonesia sits where plates meet. That is why it has so many volcanoes. It is part of the Ring of Fire.
Magma has gas trapped inside it. It is like the bubbles in a fizzy drink. The bubbles push and push. The pressure builds up! When the push gets too strong, the volcano erupts! Magma, gas and ash burst out. Magma that comes out is called lava.
In the lesson, your child puts this cause-and-effect chain in order: Earth's plates move → Rock melts into magma → Gas bubbles build pressure → Magma pushes up → The volcano erupts → Lava and ash come out.
Can volcano ash travel far? Yes! Ash can fly very far on the wind. It can even stop planes from flying.
Is volcano soil useful? Yes! Old ash makes very rich soil. Farms in Java and Bali grow lots of food.
Try it with your child
Let's do a fizzy test with a grown-up! Go outside first. The grown-up gently shakes a small bottle of fizzy drink. The grown-up slowly opens the cap, pointing it away. Whoosh! The gas bubbles push the drink out. Magma gas pushes in the same way.
Safety: Safety first: a grown-up opens it outside, pointing away from people.
Explore it together in the full lesson
Guess, find clues, build the chain and try the experiment. Read it together.