James Moon, Age 12, Of Huntsvi11e, Ala.., for his question:

What causes a whirlwind?

A dizzy little whirlwind is born on the ground and spins its merry dance up and over the roof tops. It may be born out on the wide prairies and waltz along a weaving path from side to side. We do not actually see the whirling air, but we know it is there because we see the dust, scraps of paper and other light debris it lifts and swirls aloft.

A whirlwind occurs when the sun warms a patch of air near the ground. The warm air expands and rises. Cooler air from all sides flows in to fill up the column of thinner air. The currents of air spiral around. As they flow inward and. Whisk aloft. The whirlwind dies down when the warm and the cool air are evenly mixed together.