When you hear volcano, you might think of a mountain with hot ash and fire spewing from the top. But not all volcanoes are mountains. A volcano is any place on the surface of the planet where melted rock, gases and fiery debris erupt and ooze through Earth’s crust. Some are domes, some are shields, some are mountains—but they all start in the same place.
Earth’s surface is called the crust, and it is made of solid rock. Below the crust is the Earth’s mantle. The mantle is very hot. Sometimes the heat melts the rock in the Earth’s crust.
Volcanoes form when melted rock reaches the Earth’s surface. We call the melted rock lava. Volcanoes erupt, pouring out hot lava, gases and ash. Sometimes the eruption is a big blast. Other volcanoes simply ooze lava for a long time.
Activity: You can make a model volcano erupt in the safety of your own home.
2 tsp. baking soda
2/3 cup vinegar
4 tsp. red-colored gelation powder
8 oz. plastic cup
1 plate or large dish
1 tablespoon (optional)