Why Are Volcanoes So Loud When They Erupt?

Volcanoes are so loud when they erupt because pressure builds up inside them, like a balloon being squeezed too tight.

Imagine you have a big balloon filled with air. If you keep blowing more air into it, eventually it will pop, BOOM! That’s what happens in a volcano. Inside the Earth, there's magma (hot melted rock) that moves around. When it starts to come up through the volcano, it pushes against the rock above it like the balloon being squeezed.

When the pressure gets too high, the rock can’t hold on any longer, CRACK!, and all that built-up energy bursts out in a loud eruption. It’s like when you pop a balloon with your finger, you hear a big noise because the air inside suddenly rushed out.

Sometimes, volcanoes even make loud rumbling sounds before they erupt, just like when you feel a balloon getting ready to pop, it makes a soft whoosh sound as the air starts to escape.