Kathleen Samay, age 11, of Hobart, Ind., for her question:
WHAT IS LIGHTNING MADE OF?
A dark storm spreads far and wide and towers high in the sky. Weathery warfare begins with a dazzling flash of lightning, like a crooked fiery dagger. Then comes the thunder, like the roar of distant guns. Actually the thunderstorm is a sort of battlefield. But the opposing armies are airy breezes, warm and cool, damp and dry. The lighting and thunder are caused by electricity.
On a frosty morning, your hair tends to crackle and cling to the brush. This strange event is caused by static electricity. It happens because atoms are surrounded by tiny electrons, and many of them are eager for a chance to leave home. These tiny atomic particles are mini charges of negative electricity. And negative electricity attracts positive electricity. Free electrons in your hair are attracted to positive charges in the brush. When the two meet the charge is neutralized, often with a quiet crackle.
Something like this happens in a dramatic thunderstorm, only on a much grander scale. The cloud is a frantic turmoil of airy breezes, blowing hot and cold, damp and dry, in all directions. In the wild hurly burly, whole armies of electrons are brushed away from airy atoms and molecules.
These tend to gather in a certain part of the storm cloud, where they build up an enormous charge of negative electricity. Meantime, as atoms loose negative charges, they are left with extra positive charges. So opposite charges build up in other parts of the raging storm.
The positive and negative fields attract each other, even across miles of misty cloud. Suddenly this force becomes too strong, and the two opposites meet in a flash of lightning. This is called an electrical discharge because, for the moment the two opposite charges are neutralized.
The moist cloud tries to resist the seething flash of energy. So the lightning zigs and zags to find the easiest path. In a split second, another flash follows along the same crooked path.
In less than a moment, the air around the lightning's path becomes very hot. Hot air expands, but here it is trapped by the cool, moist air around it. So it explodes with a roar of thunder. The lightning is an electrical discharge between two parts of a cloud or between a cloud and the ground. The thunder is heated air, exploding in the path of the lightning.