Science Common Sense

19 - Why do volcanoes erupt?

A volcano erupts when there's too much pressure inside the Earth. Here's what happens:

1. Magma (hot, melted rock) builds up deep inside the Earth.
2. The pressure grows as more magma comes in.
3. The pressure gets too strong, and the magma bursts out through a weak spot in the Earth's surface (the volcano).
4. The sudden release of pressure creates an eruption of lava, ash, and gas.

Think of it like a soda bottle that's been shaken up. When you open it, the pressure inside makes the soda spray out really fast. It's kind of like that with volcanoes!