Denise Sykes, age 12, of Gadsden, Ala., for her question:
HOW ARE LEAD PENCILS MADE?
Although they are called lead pencils, they really contain no lead. The marking material inside the so called lead pencil is a mixture of the mineral graphite and fine clay combined with certain chemicals and wax.
When graphite was first used in pencils, people thought it contained lead. Therefore, they called it a lead pencil then and many people still call them lead pencils.
To make the writing material, workers blend clay and graphite with water in high speed mixers. The mixture is then placed in machines and squeezed out of narrow openings as one long black string of writing material. The string is cut into pieces about seven and a quarter inches long. The pieces are then hardened in firing ovens. Finally, the pieces are treated with wax so they will write smoothly.
The wood cases for most pencils are made of incense cedar. This wood has a soft, straight grain or pattern that permits easy sharpening without splitting or splintering.
Workers saw the cedar logs into slats or narrow strips seven and a quarter inches long, a quarter of an inch thick and two and three quarters of an inch wide. The slats are heated in an oven to remove moisture. Then workers cut nine parallel grooves in each slat.
Strips of the hardened graphite and clay mixture are laid in the grooves and another slat is glued on top, making a sort of sandwich. The sandwich is then dried and cut into nine pieces, each in the shape of a pencil.
Workers use machines to sand the pencils until they are smooth. Then they apply several coats of varnish to give the pencils a shiny finish. A machine then stamps the pencils with the name of the maker.
Another machine cuts a small shoulder or rim at one end of the pencil. Workers place a ferrule or brass ring on the shoulder, put an eraser in the ferrule, and clamp the eraser in place.
Colored pencils are made in much the same way as lead pencils. They also contain clay and wax, but the clay and wax are mixed with coloring materials called pigments and dyes, rather than with graphite. Colored leads are made from dyes and widely used because their marks can be removed with soap and water.
Mechanical pencils usually have a metal or plastic case. The leads used in mechanical pencils are similar to those used in wood cased pencils. Mechanical pencils are convenient because they donut require sharpening.
Pencils are the most widely used tool for writing and drawing. The number of pencils sold each year is about double that of all other writing tools combined. More than two billion pencils are sold each year in the United States alone. This comes out to about 10 pencils for each person in the country.
The word pencil comes from the Latin penicilius, which means "little tail" or "little brush." The ancient Greeks and Romans first used pieces of lead as pencils before the birth of Christ.
The English made the first graphite pencils, in the mid 1500s. The Germans were the first to enclose graphite in a wood case, about 1650. In 1795 a Frenchman named Nicolas Conte developed a pencil making process that is still used today: he bound graphite with fine clay.