Fazale Rana, age 13, of Spencer, W. Va., for the question:

WHAT IS FIBERGLASS?

Glass, as we all know, allows us to see outdoors when we are indoors. We also eat off it, drink out of it and cook in it. In its many forms it is a perfectly marvelous substance, but who on earth would have believed it could be used to make cloth, automobile bodies and boat hulls?

Fiberglass is exactly what its name says  fibers ofglass. The fibers may be thinner than a human hair, but they are strong, flexible and resistant to moisture, oil and extreme temperatures. In addition they will not burn, stretch, rot or fade. With impressive credentials like these, it is no wonder that many industries have found countless uses for fiberglass.

The raw materials for fiberglass are the same as for glass  a large amount of sand plus smaller amounts of lime and soda. Other ingredients may be added depending on the desired qualities of the finished fiberglass strands.

Silken strands of fiberglass are produced in a number of ways. In one method the raw materials are melted together and formed into small glass balls. After cooling, the balls are inspected for impurities. Those that make the grade are placed in special electric furnaces that remelt them. When the molten glass reaches the proper temperature, it is poured through tiny holes where it forms into threads.

Steam or pressure may be used to force the hot liquid glass through the holes. In this case the size of the holes and the amount of pressure determines the thickness of the individual strands. The fibers are then wound on spools. Another method uses a spinning drum to catch the hot fibers as they emerge from the holes. Since the drum spins faster than the glass flows, tension pulls the fibers, making them even finer.

The spinning drums which wind the fibers can pull out about 176 feet of fibers in one second. Each strand is so thin that it would take a bundle of 20 fibers to be as thick as a human hair. The fibers may be twisted together in yarns that can later be woven into fabrics.

Cloth made from fiberglass is superior, in some respects, to other fabrics. It does not wrinkle or soil easily, and generally needs little ironing after washing. Because of these and other qualities it is widely used for curtains, draperies and tablecloths. When fiberglass is combined with other materials it can be pressed into sheets or molded into various forms. Boat hulls and automobile bodies can be pressed out on huge hydraulic presses.

Fiberglass, in different forms, can be used for insulation of electric wires or spread in the attic and walls of a house to keep it cool in the summer and warm in the winter. Since its development in the 1930s fiberglass has grown into a multimillion dollar industry.