what is volcano and what is the reason behind it?
Answers
Volcanoes are just a natural way that the Earth and other planets have of cooling off and releasing internal heat and pressure.
Volcanoes erupt because of density and pressure. The lower density of the magma relative to the surrounding rocks causes it to rise (like air bubbles in syrup). It will rise to the surface or to a depth that is determined by the density of the magma and the weight of the rocks above it. As the magma rises, bubbles start to form from the gas dissolved in the magma. The gas bubbles exert tremendous pressure. This pressure helps to bring the magma to the surface and forces it in the air, sometimes to great heights.
here is ur answer
it is an opening on the surface of the planet that allows material warmer then it's surroundings to escape from it's interior.
the reason behind it is when magma rises to the surface of the earth ,which cause bubbles to gas to appear in it.