Facts about Volcanoes

What is a Volcano?
A volcano is a landform (usually a mountain) where molten rock erupts through the surface of the planet.
In simple terms a volcano is a mountain that opens downward to a pool of molten rock (magma) below the surface of the earth. It is a hole in the Earth from which molten rock and gas erupt.

Did you know?
The name "volcano" has its origin from the name of Vulcan, a god of fire in Roman mythology.
As pressure in the molten rock builds up it needs to escape somewhere. So it forces its way up “fissures” which are narrow cracks in the earths crust. Once the magma erupts through the earth’s surface it’s called lava.

What is the difference between lava and Magma?
Magma is liquid rock inside a volcano.
Lava is liquid rock (magma) that flows out of a volcano. Fresh lava ranges from 1,300° to 2,200° F (700° to 1,200° C) in temperature and glows red hot to white hot as it flows.

How many volcanoes are there in the world?
There are around 1510 'active' volcanoes in the world. We currently know of 80 or more which are under the oceans.

What are the three layers the Earth is made of?
1.Crust
The crust is the outer layer of Earth. It is about 18 miles thick. It is the part we live on.
2.Mantle
The second layer is called the mantle. It is about 1,800 miles thick.
3.Core
The inner layer is called the core.

What causes volcanoes to erupt?
The Earth's crust is made up of huge slabs called plates, which fit together like a jigsaw puzzle. These plates sometimes move.
Between the Earth's crust and the mantle is a substance called magma which is made of rock and gases.
When two plates collide, one section slides on top of the other, the one beneath is pushed down. Magma is squeezed up between two plates.

Did you know?
Volcanoes are like giant safety valves that release the pressure that builds up inside the Earth.

When magma erupts, what is it called?
hen magma erupts through the earth's surface it is called lava

What is the Ring of Fire?
Over half of the world’s volcanoes arise in a belt around the Pacific Ocean called the Ring of Fire.

FUENTE:
http://www.woodlands-junior.kent.sch.uk/Homework/mountains/volcanoes.htm