The pencil “lead” is actually a mixture of graphite and clay. More clay in the mixture makes the lead harder. A harder lead has a higher number. Pencils are numbered from 1-3 but most people use a ...

No.2 pencils are widely used, but you may not know what the number actually refers to. This video explains how pencils developed into their modern form and the significance of the labeled numbers.

Pencils, erasers, ballpoint pens - it was ... of paper), or a wax layer on a piece of wood. Some styluses were made of lead, which became popular - but as the centuries rolled on, graphite found ...