A volcano is a mountain that has opening on its tip. The tip is called as the crater. Time will come that a volcano explodes and some gases and rock fragments inside the Earth will vent out into the surface.
The volcano is formed when Magma rises close to the surface. Magma is the melted rocks from the Earth’s crust. At first, magma rises close to the surface and then it may find a crack. As the magma flows, it will grow wider and longer until it will comes into the surface of the Earth. The magma will continue to deposit into the surface through time until the mountain builds up.
Volcanoes are classified according to the shape of their cones. There are the Lava Cones; these cones are having a gentle slopes and broad base. They are usually formed when the lava flows from the center going down to their slopes.
There are the Cinder Cones; cinder cone volcanoes are usually formed from ashes as well as dust materials. These materials are thrown up into the air; they are hardened before they came further down. They have a usual explosive eruption, sometimes violent as well as destructive.
There are also the Strato volcano; strato volcano usually formed by alternate layers of lava. Volcanoes are sometime grouped according to their activities. Some volcanoes are active while others are dormant. Active volcanoes erupt frequently just in a short period of time. Dormant volcanoes on the other hand, are quiet and remain no activity for a long period of time but may soon be again active. Some volcanoes are extinct volcanoes. These volcanoes remain dormant for a long time.