Name: Explaining how a touchscreen works with a sausage | The Secret Genius of Modern Life - BBC
Uploaded: 2025-04-12T21:01:10.000Z
Duration: 4 min 11 s
Description: Thousands of YouTube videos with English-Chinese subtitles! Now you can learn to understand native speakers, expand your vocabulary, and improve your pronunciation...

Okay, I want you to imagine for a moment it's 2010.

And it is one of the coldest winters on record, there's snow everywhere, and everyone, as they have a habit of doing in winter is getting really annoyed about the fact that they can't use their smartphones while they're wearing gloves.

Please excuse typos, I'm writing with a sausage.

I spent eight years at university studying mathematics.

Now, this became so popular that one sausage manufacturer said that they actually had a 40% increase in sales.

Anyway, once you've wiped all the greasy sausage slime off your phone.

You're left with a very handy treat for your way home. Delicious.

What could bangers do that gloves couldn't?

You might imagine that the screen on your smartphone is just a simple sheet of toughened glass.

But actually, hiding inside it is a very fine mesh of something called indium tin oxide.

Now, indium tin oxide has a very special quality, which is that it is able to store charge and conduct electricity.

You can't see it on your phone screen because the mesh is transparent.

So let me explain what it does using something that we can see, a phone case and some polystyrene balls.

In the real phone, you have got a layer of glass, which acts as an insulator, using plastic here.

And then underneath it, that grid of indium tin oxide is charged, which creates an electric field.

And that is something we can mimic using this and a woolly jumper in order to just impart some static electricity magic in there.

It's actually the director's, but she's she dresses like an 80 year old.

So my polystyrene balls are now the stored electric charges in the grid.

But our bodies actually have something in common with indium tin oxide, which is that we too are able to store charge and conduct electricity.

And so, when the charge from my finger comes close to the charge stored in this grid on the phone, it disturbs the electrostatic field.

This is not me pushing these balls around here. It's the interaction between the stored charges of these two conductors, your finger and the grid inside your phone that makes this touchscreen work.

Your phone's processor can detect these field changes and pinpoint the exact location of your touch.

And that essentially means that anything that has that similar property, anything that also can store charge and conduct electricity will be able to make your touchscreen work, so something like a sausage will do very nicely.

Or just get yourself a handy pickle, which will work just as well. My phone is going to stink.

Like the pickle, we are mostly made from salty water, and that's what allows us to store charge and conduct electricity.

But materials that are insulators, something like a fork, for instance, and don't allow electricity to pass through, they won't work.

Not doing anything, and neither does a gloved hand.