Why do volcanoes erupt?
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If you could peek inside a mountain, what do you think it would look like in there?
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Transcript
Have you ever wondered why volcanoes erupt?
Deep under the ground, rocks get so hot that they melt into a thick glowing liquid. This melted rock is called magma, and it hides far below our feet.
Magma is lighter than the hard rock around it, so it slowly floats upward through cracks. Tiny bubbles of gas inside it grow bigger and bigger as it rises.
When the magma and bubbles reach the top, they burst out as fiery lava, smoke, and ash. That fiery burst is what we call a volcanic eruption.
So that's why volcanoes erupt: hot melted rock and gas push their way up and burst out the top!
For grown-ups: the science
Deep underground, rock gets so hot it melts, and the melted rock and bubbles push up and out of the mountain.
Volcanoes form above places where intense heat in the Earth's mantle melts rock into magma. Magma is lighter than solid rock, so it rises through cracks toward the surface. Dissolved gases in the magma expand as pressure drops, and when the pressure gets too strong, it bursts out as an eruption, releasing lava, ash, and gas.