How does a volcano erupt??

We have heard about many different volcanoes. Some are in an active state and some are dormant. The million dollar question is that "How does a volcano erupt?"

Well here comes the explanation to this question..

Volcanoes usually erupt because of lot of intensity and pressure beneath the earth surface. Density also comes into picture when we think of a volcano eruption. The lower density of magma usually causes the magma to rise in level. This magma then rises to the surface or to the depth which is determined by the density of the magma and also the weight of the rocks above it. When the magma begins to rise, bubbles starts forming from the gas dissolved in the magma. These gas bubbles start exerting a lot of pressure which helps in bringing the magma to the surface. Sometimes this pressure is so high that the magma level may rise to greater heights thus forcing it into the air.