Wayne Demchak, age 13, of Santa Maria, California, for his question:

Does black light harm the eyes?

What we call black light can be extremely dangerous to eyes, skin and all living cells. Actually it is ultraviolet radiation. Its wavelengths are slightly longer than penetrating X rays, but up to 100 times shorter than the blue violet rays of the visible spectrum. The average sunlamp produces ultraviolet radiation in a quartz or fluorite tube, so that its skin tanning rays can shine through. A pair of very special dark glasses comes with the purchase. They should be worn to protect the eyes, each and every time the lamp is turned on.

Solar radiation pours forth enough ultraviolet radiation to destroy almost everything living on the earth. But our wonderful old planet shields its children with an enormous global umbrella that screens out most of the dangerous rays before they reach the earth. In small doses, ultraviolet light is beneficial to health. It also haw many uses in industry and as a germicide in food preparation.