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Volcano

Key Stage 2

A picture of an active volcano.

Meaning

A volcano is a mountain made from lava that has cooled to become rock.

Key Stage 3

Meaning

A volcano is a mountain made from lava that has cooled to become igneous rock.

About Volcanoes

Volcanoes are usually found near the boundaries between tectonic plates.

Once a volcano is formed it goes through 3 stages of existence :

1. Firstly as a volcano is erupting or has recently erupted it is known as an Active Volcano.
2. Secondly when a volcano is not currently erupting but is due to erupt again within a period of ten thousand years since its last eruption it is known as a Dormant Volcano.
3. Finally if a volcano has not erupted in over 10,000 years it is classified as an Extinct Volcano. This means that it will never erupt again.

Key Stage 4

Meaning

A volcano is a mountain made from lava that has cooled to become igneous rock.

About Volcanoes

Volcanoes are usually found near the boundaries between tectonic plates.

How Volcanoes are formed

Volcanoes are formed along 2 different types of tectonic plate margin; Destructive Plate Margins and Constructive Plate Margins.

At Destructive Plate Margins more dense oceanic plate moves under the less dense continental plate. As this happens the oceanic plate is melted and a lot of magma forms in a large pool. This magma then rises towards the surface of the crust through cracks in the crust called vents. As this magma reaches the surface an extremely violent Volcanic Eruption is created due to high pressure that built up as the magma moved through the vents being released. Once this Volcanic Eruption had occurred the lava that was produced cools and forms rock in the form of a mountain. This is a Volcano

At Constructive Plate Margins two Tectonic Plates are moving away from each other and this creates a very large and deep gap. Magma rises up towards the surface of the earths crust through this gap. This then causes the magma to erupt as it reaches the surface of the crust. This is a much less violent eruption as the magma has risen through a much wider gap than the size of the vents at the Destructive Plate Margin and therefore less pressure is built up and the volcanic eruption is less explosive. The lava that has erupted then solidifies into rock and a volcano is formed.

Beyond the Curriculum

References

AQA

Volcano, pages 292-3, 295-7, 315, GCSE Chemistry; Student Book, Collins, AQA
Volcanoes, pages 168, GCSE Combined Science Trilogy 2, Hodder, AQA