Why volcanoes erupt
Magma does not blast out because it is hot. It erupts because dissolved gas comes out of solution as it rises, like a shaken bottle.
Why volcanoes eruptMake one like this
Transcript
Heat trapped below
Deep inside Earth, rock stays hot enough to melt.
About sixty-five kilometers down, the temperature reaches 1,200 degrees Celsius.
That melted rock is called magma, and it weighs less than solid rock around it.
Because magma is lighter, it wants to rise toward the surface.
Gas pushes upward
Magma contains dissolved gases: water vapor, carbon dioxide, sulfur dioxide.
As magma rises and pressure drops, those gases bubble out, like fizz escaping soda.
The expanding gas pushes the magma upward faster and faster.
This pressure is the engine that drives an eruption.
Cracks in the crust
Magma follows the weakest path through Earth's crust.
It finds cracks, fractures, and old volcanic pipes where rock already broke.
In the Western Pacific, the Ring of Fire contains about seventy-five percent of Earth's active volcanoes.
Most sit where two tectonic plates meet and create weakness in the ground.
The moment of eruption
When magma reaches a chamber near the surface, pressure builds inside like a sealed bottle.
If the overlying rock cannot hold back the force, it cracks.
Magma, gas, and broken rock blast upward in minutes.
What was hidden pressure suddenly becomes visible: lava, ash, and sound.
Why it stops
An eruption ends when the magma chamber empties or pressure inside drops enough to seal the vent.
Rock cools and hardens, blocking the path.
But the heat below never stops; in weeks, months, or years, pressure builds again.
A volcano is not a one-time event—it is the surface expression of Earth's unending internal heat.
Every sentence above was written before a single picture was drawn, then each object it names was painted for this video alone.
Make your first video free