Ready, Set, Erupt!

A volcano is a mountain. It has a hole at the top. Some volcanoes have hot melted rock inside. Learn more about volcanoes below.
Volcanoes can erupt
erupt
PETER CADE—GETTY IMAGES
to burst out; to explode
(verb)
The audience erupts with laughter.
.

Ash
ash
PAUL SOUDERS—GETTY IMAGES
the soft powder that remains after something has burned
(noun)
The volcano pushed clouds of ash into the air.
and lava
lava
WESTEND61—GETTY IMAGES
hot semiliquid rock that flows from a volcano
(noun)
Lava burst out of the mountain.
shoot out of a volcano. Lava is hot. It flows down the volcano.
Volcanoes can be quiet.

Not all volcanoes are active. Some are dormant. This means that they have not erupted in a long time.
People study volcanoes.

Volcanologists are scientists. They study volcanoes. They check to see if volcanoes are active
active
JOHANN K JOHANNSSON—GETTY IMAGES
capable of producing action or movement; likely to erupt
(adjective)
Most of the island's volcanoes are active.
. They warn people if one will erupt soon. This saves lives.
Volcanoes can form land.

Lava cools into rock. This forms new land. Hawaii was formed by volcanoes. Diamond Head volcano is in Hawaii. It is not active.
Did You Know?

Magma is hot liquid rock. It is deep inside the volcanic mountain. When it erupts out of the mountain, it is known as lava.