<http://schema.org/articleBody>
"  (Photo by AP Photo/Joe Berti) For most people, images of a towering mushroom cloud rising over the horizon immediately bring to mind a nuclear weapon detonation. But this iconic shape is produced by large explosions on the ground, courtesy of simple physics\u2014that&amp;#039;s why one appeared after yesterday&amp;#039;s explosion at a fertilizer plant in West, Texas. This cloud appeared after the detonation of a 2000-lb bomb, which PM photographer Chad Hunt witnessed at a Marine Corps training facility in California during our recent visit.  (Photo by Chad Hunt) And here&amp;#039;s the archetypal mushroom cloud, one that appeared after a nuclear bomb test at Frenchman&amp;#039;s Flat in Nevada in April 1951.  (Popperfoto/Getty Images) Each of these blasts produced a pyrocumulus cloud shaped like a mushroom. The physics is the same in each case: The explosion produces hot gas that quickly rises. The air above actually blunts this hot gas as it tries to move upward, literally pushing it downward and forming the distinctive cap.  Ask a physicist about this phenomena and he or she would talk about the Rayleigh-Taylor instability, which describes the interaction between two materials (fluids or gasses) of different densities when they are forced together. In an explosion, the less dense hot air is meeting the more dense cold air and (not to be too technical) smooshing into a mushroom shape. That&amp;#039;s why mushroom clouds aren&amp;#039;t confined to nuclear explosions. In our visit to the Marine Corps training ground, we saw them appear after even 1000- or 500-lb. bomb blasts. "^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.popularmechanics.com/military/weapons/a8900/mushroom-cloud-physics-not-just-for-nukes-15363683/>