q The lightning stroke can heat the air through
which it travels to 30,000ºC (54,000ºF), which is 5 times hotter than the surface of sun.
qThis extreme
heating causes the air to expand explosively, thus initiating a shock wave that become a booming sound wave (thunder) to travel outward.
q It takes 3 seconds for thunder to travel 1 km
(5 seconds to
travel 1 mile).