Kristin Keen, age 12, of Champaign, Ill., for her question:

WHEN WAS COAL FIRST USED?

There is historical evidence that coal was first used 3,000 to 4,000 years ago, in the Bronze Age. At that time, the people of southeastern Wales used coal for funeral pyres to burn their dead.

King Solomon was probably familiar with coal deposits of Syria because coal is mentioned in the Bible. The Greeks also used coal several hundred years before the birth of Christ. But then hundreds of years passed before coal had any great and lasting influence on the course of civilization.

During the Middle Ages in England, coal was commonly thought to be a curse. People thought it filled the air with dangerous poisons. In 1306, King Edward I of England issued a proclamation that declared the use of coal punishable by death.

The word "coal" in the English language comes from the Anglo Saxon "col," which originally referred to charcoal. The spelling "cole" was used until about 300 years ago, when the present spelling of the word, "coal," was adopted.

In the early days, the methods of burning coal were so inefficient that smoke and bad odor filled the air. But the English eventually solved these problems. The industrial revolution, which dates from the 1700s, was largely dependent on coal as the chief source of power to drive steam engines.

Coal was used by white settlers in North America in the late 1600s. Some of the Indian tribes knew about coal long before this. The Pueblo Indians of the Southwest, as an example, used coal in their pottery making at an early age in America.

With the growing industrialization after 1850, coal was increasingly used in the United States. The growth of railroads gave the coal industry one of its largest customers and also stimulated the iron and steel industry, another large user of coal.

In the late 1890s, the development of steam driven electric generators sparked the growth of the electric power industry, the modern coal industry's largest customer.

Coal supplies the fuel used to generate over half the electric power in the U.S. today. Coal is burned under boilers containing water and steam from the boiling water spins turbines that turn generators to produce electricity.

One ounce of coal can make as much electricity as 100 tons of water falling one foot.

The electric utility industry uses about 300 million tons of bituminous coal a year. The aluminum industry, which consumes large quantities of electricity, is building plants in coal regions. This puts the plants close to low cost sources of electric energy.

Steel is not usually made in large amounts without coke, which is bituminous coal with the tar and gases baked out.

Coal is also used to produce chemicals from which thousands of useful items are made. Included are synthetic fibers, drugs, plastics, detergents, fertilizers, explosives, roofing materials, food preservatives, synthetic vitamins and a wide variety of pharmaceuticals.