Pencils, Rubbers et al

Why does a rubber rub out pencil?

People are so nasty and horrible these days that if you ask a perfectly reasonable question they’ll say, ‘why don’t you google it, asshole.’ (It is possible to make these people look stupid by asking a rhetorical question…)

Back in the day, when I were a lad, I spotted a gap during a chemistry lesson, raised my hand and asked: “Why does a rubber rub out pencil?”

The class erupted in hysterics and I didn’t get a straight answer from the teacher. Later I asked my mate Paul Reid why everyone laughed. “Because only you would think of asking a question like that.”

Nearly four decades later I still don’t understand the physics of pencil erasers, so if anyone knows (serious answers only, no speculation) do leave a comment.

It’s not the only trivial bit of science that baffles me. Inkjet printers. We all take them for granted, hate them when they go wrong, and we know they’re designed to waste ink and therefore waste our money. But have you ever wondered how incredible they are from a technological point of view?

They can deposit a microscopic blob of ink anywhere on a sheet of paper no matter how big. This from a mechanical object. It’s not like a computer screen using algorithms and formulas to calculate which screen pixel to electrify. Printers have to move bits and pieces backwards and forwards, accurately, every time until the cyan cartridge runs out.

We don’t think about brilliance when the brilliance has become the everyday. What we take for granted seems simple, but it seldom is. Live events on television should astound you if you took a moment to think about what’s going on. All those tiny people running around a football pitch in Nice are not actors, it’s not a recording or a computer simulation, they really are there, thousands of miles away kicking a ball nanoseconds before you see it happen.

The technology, the speed of light broadcasting of an electronic signal is related to mobile phone technology. Take a look at that small oblong of plastic. Press the right button and some invisible connection is made to a mast somewhere, miles away. And the invisible connection travels through walls, through people’s heads, that passing bus is no obstacle. Everything between the phone and the mast is a conduit for the signal: electrons in the baby’s pram, the dog’s tail, the back fence, the cake display in Galloways, all vibrating and jumping to the next electron level to carry that mobile signal. No wonder everyone’s going mad with all the electromagnetic stimulation we’re bombarded with every day.

Hundred ton planes flying, thousand ton ships floating. It’s simple physics say the egg heads, but simple is still extraordinary.

I suppose if Aristotle had jumped out of his bath shouting eureka ten minutes earlier we might have had mobile phones forty years earlier and then I could have used mine to find out why rubbers rub out pencil. There’s nothing on the internet. Not even on google.