Pam Dorsey, age 11, of Florence, S.C., for her question:

HOW IS GUNPOWDER MADE?

Gunpowder, or black    powder, is an explosive made offinely ground potassium nitrate, sulfur and charcoal. oldest of all explosives, it was used by the ancient Chinese and Arabs. Exact directions for making it did not reach the Western world until about 1242 when Roger Bacon of Oxford University wrote a book dealing with the subject. Today, there are many better explosives than gunpowder, but it is still manufactured, and the basic recipe remains pretty much the same.

The proper portions of potassium nitrate, sulfur and charcoal are mixed together and ground in a mill. When the particles reach the right size they are passed along to another machine that presses them together to form a solid cake. The cake is then broken into grains of a desired size. At one time making explosives was a very dangerous occupation. Today, thanks to modern safety measures, the explosives industry has one of the best safety records in the United States.