Thunder
The sound
emitted by rapidly expanding gases along the channel of a lightning
discharge. Over three-quarters of lightning's electrical discharge
is used in heating the gases in the atmosphere in and immediately
around the visible channel. Temperatures can rise to over 10,000
°C in microseconds, resulting in a violent pressure
wave, composed of compression and rarefaction. The rumble of
thunder is created as one's ear catches other parts of the
discharge, the part of the lightning flash nearest registering
first, then the parts further away.