Volcanoes

Deep down, rock sometimes melts into magma. Being lighter than the solid rock around it, magma rises and gathers in a magma chamber; when the pressure of its gases is high enough it erupts up the vent and out of the crater, building a cone of cooled lava and ash. On the surface it is called lava. A volcano gives out solids (rock and ash), liquid (lava) and gases, mostly steam and carbon dioxide. Volcanoes are dangerous, but they also give fertile soil, light rocks like pumice, hot springs and new islands. A volcano may be active, dormant or extinct; Damavand, Iran's highest mountain, is a volcano that still lets out gas.