In the film 'Sweet Home Alabama' it is implied that when lightning strikes sand, the quarz in the sa

In the film 'Sweet Home Alabama' it is implied that when lightning strikes sand, the quarz in the sand turns into a glass sculpture similar to a plant root. In one scene, someone is ramming steel rods into the sand, presumably to provoke such a strike. Is this fact or fiction?

Christian Kuepers, Croydon Surrey

• Lightning stikes do indeed fuse sand into cone- or root-like structures, but the phenomenon is rare. These objects have been termed 'fulgerites' meaning 'thuderbolt stones'.

  Paul Barrett, London UK

• http://plaza.ufl.edu/rakov/Gas.html

  Adrian, Bedford, UK

• Fulgurites are real, but aren’t quite the exotic, clear sculptures shown in the movie.

  Billy, Georgia, US

• Fiction.

  Randy, Houston, USA