Although I frequently talk about the latest high tech developments, I sometimes write Science Shorts using a very reliable low-tech word processor called a pencil! Far from being made obsolete by the computer, as many as three billion pencils are produced in North America every year. Each is capable of processing around fifty thousand words.

The humble pencil can be precisely tailored to the job we want it to do. Pencils are produced using a twenty point scale, going from 10H at the hard end, to 8B at the soft end.

The black core of the pencil has not been made of lead since the sixteenth century. It’s made by mixing fine particles of carbon in the form of graphite with a kind of clay used for making bone china, and water. The resulting putty-like substance is forced through a small hole to produce a lead of an appropriate diameter. After drying, the graphite-clay mixture is baked in a kiln at high temperature.

The different blackness and hardness of pencils are produced by mixing the graphite and clay in different proportions. The more clay, the higher the H number, so that 6H is harder than 4H. Since graphite has a flaky layered structure, it easily flakes off when pressed against paper, leaving black marks which we form into words.

So next time you have to process words, don’t forget about the inexpensive, reliable pencil.

Bob