How does a pencil work?

A pencil writes because gray dust rubs off. The hard tip touches paper. It leaves dark lines. The wood helps you hold it.

A pencil has a soft, dark stick inside the wood. When you push it on paper, tiny bits rub off and stay on the paper. That makes the line you see. It is like rubbing a crayon on paper, but the pencil mark is thinner. The wood helps you hold it and keeps the dark stick from breaking.

A pencil’s “lead” is not really lead. It is graphite, a soft, dark material, mixed with clay to make it stronger. When you drag the tip across paper, tiny flakes of graphite scrape off and get caught on the paper’s rough surface. That makes the gray line you see. More clay makes a harder, lighter pencil; more graphite makes a softer, darker one. Fun fact: one pencil can draw a line many miles long before it is used up.