What causes volcanoes to erupt and what are the different types?

Volcanoes erupt when pressure builds up inside Earth and then suddenly lets out like a shaken bottle of soda.

Imagine you have a big jar filled with beans, and there’s a lid on top. If you shake it hard enough, the beans push against the lid until BOOM!, they all come flying out. That's kind of what happens in a volcano!

Inside Earth is molten rock (called lava), which is hot and moves around like soup in a pot. When this molten rock gets trapped below the ground, it starts to build up pressure. Over time, that pressure can be so strong that it cracks through the ground, POOF!, eruption!

Some volcanoes are big and sleepy, erupting every few years. Others are like fireworks, BAM!, they explode in a big show, then go quiet for a while.

There’s also a type that looks like a mountain with a hole on top, called shield volcanoes. They’re shaped like giant shields because lava flows out slowly and smoothly.

And there are fissure volcanoes, which look like long cracks in the ground, lava comes out of them like a river from a broken dam!

Volcanoes are like Earth’s way of saying, “Hey, I'm full of hot stuff!”