Why Do Volcanoes Sometimes Explode and Sometimes Gently Bubble?

Volcanoes can be like big, sleepy dragons that sometimes snort and sometimes just breathe slowly.

Volcanoes are mountains made from magma, which is hot, melted rock deep inside the Earth. When magma moves up through cracks in the ground, it can come out as lava or gas, that’s what makes a volcano "breathe."

Sometimes volcanoes explode because the pressure builds up too much, like when you squeeze a balloon full of air and then let go, whoosh! The magma inside gets hotter and more bubbly, and all those bubbles can pop at once, sending lava, ash, and rocks flying out.

Other times volcanoes just bubble gently, like a pot on the stove that's only barely boiling. The pressure isn’t as strong, so the magma flows slowly out, making a calm, steady flow of lava, kind of like a quiet, sleepy dragon.

• Gentle bubbles: Not much gas or pressure, lava flows slowly.
• Big explosions: Lots of gas and pressure, everything bursts out at once!

Just like how some pots hiss quietly and others pop loudly, volcanoes can be different too.