Last updated 05 April 2013, created 20 March 2012, viewed 660
Use these pictures from the Encyclopaedia Britannica to learn about volcanoes. A volcano is an opening in Earth's crust. When a volcano erupts, hot gases and melted rock from deep within Earth find their way up to the surface. This material may flow slowly out of a fissure, or crack, in the grou More…nd, or it may explode suddenly into the air. Volcanic eruptions may be very destructive. But they also create new landforms. There are more than 1,500 potentially active volcanoes in the world today.