How Does a ‘Volcano’ Erupt and What Causes It to Sleep?

Imagine a volcano like a giant bottle of soda that's been shaken up. When it erupts, it’s like the soda suddenly fizzing out all over the place. But when it goes to sleep, it’s like the soda stops bubbling for a while. This happens because inside the Earth, hot rock called magma is moving around. If the pressure builds up enough, the volcano erupts, but if there's not enough pressure or magma left, it can go to sleep for years.