There are some inventions that look completely pointless to the untrained eye: who would ever need a motorized garbage can, an electric pencil sharpener or a battery-powered eraser? Quite often ...

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 ...

This tiny snail is not much bigger than a pencil eraser. Its body—most of it a muscular foot—is bumpy and brown, and its antenna-like eyes are almost translucent. A gland in the snail’s foot ...

The eraser was then added in 1858 by Hymen Lipman who patented the idea. Creating different hardness' to pencils was discovered by Nicholas Jacques Conté. Mixing powdered graphite with clay and ...