成人快手

Watch: Volcanoes

Back to top

What are volcanoes?

Cartoon of Mount Vesuvius.

Volcanoes can look like small mountains or hills.

A volcano is an opening in the Earth鈥檚 crust that allows magma, hot ash and gases to escape.

Cartoon of Mount Vesuvius.
Diagram of the inside of a volcano. Magma is inside it and ash is above it.

Magma is molten rock - rock that is so hot it has turned into liquid.

When magma reaches the surface of the Earth, it is called lava. Lava comes out of the volcano as a volcanic eruption, along with gases and ash.

Back to top

Where do you find most volcanic action?

Pieces of the Earth's crust, called tectonic plates, fit together a bit like a jigsaw and move very slowly.

A map of the world showing tectonic plates fitting together like a jigsaw.
Image caption,
A map of the world showing tectonic plates.

Most sites of volcanic activity are along boundaries of tectonic plates.

Map of the world showing sites of volcanic activity around the borders of tectonic plates.
Image caption,
Map of the world showing sites of volcanic activity.
Back to top

Volcanic eruptions

Cartoon of red and orange lava.

Most volcanic eruptions are caused by tectonic plates moving towards each other.

Some volcanoes, like Mauna Loa in Hawaii are caused by hot spots in the Earth鈥檚 crust. These do not erupt violently and lava usually flows slowly out of them.

Eruptions from volcanoes can be very dangerous. They can produce:

  • pyroclastic flows - fast moving clouds of hot ash, gas and rock
  • ash clouds - small pieces of rock and glass that can be carried in the air for many kilometres
  • volcanic bombs - large bits of very hot rock blown out of a volcano
Cartoon of red and orange lava.
A cartoon volcano behind a field of crops.
Back to top

Watch: What do volcanoes look like?

Back to top

Activity: Quiz 鈥 Volcanoes

Back to top

Bitesize Primary games. game

Play fun and educational primary games in science, maths, English, history, geography, art, computing and modern languages.

Bitesize Primary games
Back to top

More on The natural world

Find out more by working through a topic