A volcano is a hole in the Earth.
Melted rock and gas can come out.
Melted rock under the ground is magma.
Out on top, it is lava.
Lava cools. It turns to solid rock.
Some volcanoes are cone mountains built in layers.
Many have a crater, a round dip at the top.
Ash is tiny bits of rock. Wind can carry it miles.
Volcanoes can build chains of islands, like Hawaii.
Words to know
- crater: a round dip
- lava: melted rock out
- ash: tiny rock bits
