Part of the show Naked Science Q&A Show
Robert Sullivan asked:
Iíve always wondered, when lightning hits water does it go with a splash? Iíve asked several of my professors and none seem to have the answer.
We answered this along with Bill Gettys' question...
When lightning hits water, it suddenly dumps a huge amount of energy into the bit of water itís hitting Ė so very close to where itís hit it will form steam. When lightning hits sand it releases so much energy it causes sand to melt and turn into glass. It would probably vapourise the water near where itís hit and cause a bubble of steam which probably will cause a splash.