Freedman, David H. Bolts From the Blue. Discover Magazine. Vol. 11 No.
12. December, 1990.
Abstract: This article explains the physics of lightning. In detail,
the article explains how separated positive and negative charges in clouds
result in lightning flashes. The article also explains the different types
of lightning. A single lightning flash usually consists of several lightning
flashes and each one takes about one fiftieth of a second. Another type
of lightning has continuous currents that can last one full second. This
type of lightning is very dangerous and is usually responsible for starting
forest fires. Scientists do not know much about lightning, especially why
it occurs. There are conflicting theories, none of which have been proven
correct. One theory credits precipitation as the cause of lightning. The
other popular theory states that convective updrafts and downdrafts are
responsible for the electrical outbursts. The other important question scientists
are struggling to answer is how lightning chooses its targets. Experiments
are currently underway to explain this mystery.