Thompson, age 12, of Seattle, Wash., for her question:

 What is tungsten?

In the world of chemistry it may be called wolfram, and the chemical symbol in its slot on the Periodic Table of Chemical elements is the letter W. In the world of industry and machines it may be called tungsten. Wolfram, alias tungsten, is a rare and durable metal of silvery white.

This sturdy metallic element was discovered by a German scientist in 1783 and given the name wolfram in his honor. In Sweden, however, it was given the name tungsten, meaning the heavy stone. The name wolfram was adopted by the world of science. The name tungsten became popular with the practical people who found uses for the tough element in the manufacturing of metal alloys and electronic equipment, dyes and fireproofing for the textile industry.

In everyday language it is most often called tungsten. In everyday life, as a rule, it is nearest to us inside an ordinary electric light bulb. The fine filament that joins the metal spikes inside a light bulb must be able to hold together and endure under great heat. Most metals soon fall apart under such conditions, but tungsten has just the right quality for the job. Its melting point is 6,170 degrees Fahrenheit. It can stand twice as much heat as iron, and its melting point is higher than any other metal.

Tungsten is also a hard metal, second in hardness only to the diamond. What's more, it shares its hardness when alloyed with other metals. Alloys of tungsten and steel are harder, stronger and more pliable than ordinary steel. Tools of tungsten steel are five times more workable than those of plain steel. Tungsten knives stay sharper and tungsten cutting machines perform at the highest speeds. Tungsten tips are used on those up to date so called painless drills used by the dentist.

Tungsten is one of the heaviest elements, almost twice as heavy as lead. It has great tensile strength and refuses to break under pressure. A rod of tungsten one inch thick can support 250 tons. It remains strong when stretched into fine threads. The filaments Used in light bulbs and vacuum tubes may be six times thinner than a human hair. Hard and durable tungsten also is used to make ammunition and automobile parts. A compound of tungsten and sodium is used for fireproofing textiles. A pasty White substance of lead and tungsten is used as a paint to which may be added an assortment of rainbow pigments.

In nature, tungsten is never found in its pure form, and the rare element makes up less than one thousandth part of 1% of the Earth's crust. Its most common ores are Scheelite and wolframate, and the job of separating the durable element from other minerals in its ores is both difficult and costly. At one time pure tungsten was more costly than gold. Most of the world's tungsten ores are mined in China. The second tungsten producing country is the United States, where the ores are mined in California and Nevada, Idaho and North Carolina.