Lightning
Even today the phenomenon of lightning is still not fully understood.
It is awesome and frightening to many and because of the mystery that surrounds it,
several cultures have developed different beliefs about it. Some African cultures believe
that when someone is hit by lightning that he/she was cursed even before the event. The
Romans and Greeks believed that the gods were fighting and this was one of their weapons.
Lightning kills and injures many people, starts thousands of forest fires, and causes
millions of dollars in property damage every year.
Lightning is characterized by the discharge of
electricity between rain clouds or between a rain cloud and the earth. It is usually seen
as an arc of extremely bright light which can be many kilometers in length, however, there
are other forms as well. Accompanying the lightning is the giant roar of thunder. The
thunder is caused by the expansion of air that has been heated by the lightning which then
collides with cooler air, creating the sound of an explosion.
Thunderstorms are the most common types of storms, and thunder itself,
although frightening, is not dangerous. It is the lightning that causes the problems.
Lightning and thunder occur together, however we hear the thunder after we see the
lightning. Sound waves travel about one mile in five seconds, while light travels at more
than 186,000 miles per second. Therefore, lightning is seen immediately when it occurs,
and thunder is heard a little later.
The different sounds of thunder (deep roar/loud crash) is caused by the
different types of lightning, for example, the thunder that has the sharp crackle like
sound is caused when the large trunk of lightning forks into many branches.