| | Volcano articles and news from Start Learning Now (Site not responding. Last check: 2007-11-05) |
 | | A volcano is a landformgeological landform (usually a mountain) where magma (rock of the Earth's interior made molten or liquid by extremely high temperatures along with a reduction in pressure and/or the introduction of water or other volatiles) erupts through the surface of the planet. |
 | | Eventually, magma in the chamber is forced upwards and flows out across the planet surface as lava, or the rising magma can heat water in the surrounding landform and cause explosive discharges of steam; either this or escaping gases from the magma can produce forceful ejections of rocks, cinders, obsidianvolcanic glass, and/or volcanic ash. |
 | | Society of JesusJesuit Athanasius Kircher (1602-1680), witnessed eruptions of Aetna and Stromboli, then visited the crater of Vesuvius and published his view of an Earth with a central fire connected to numerous others caused by the burning of sulfur, bitumen and coal. |
| www.startlearningnow.com /volcanic.htm (3648 words) |