Ten years ago mobile phones were the size of bricks, as heavy as a bag of sugar and the property of only the very rich. Now they are everywhere, smaller than a credit card and lighter than a Mars bar. But what shrunk the mobile phone, and how come we all have one? Join Tony as he explores the chemistry that connects people and asks what does the electronic chemistry have in store for us?

Professor Tony Ryan
[Tony enters the lecture theatre and runs to answer a jumbo-size 'set' mobile phone.] Hello, welcome to the third [mobile phone rings]... oh. No! Mum! I'm in the lecture theatre! [Laughter]

These things always ring at the wrong times, don't they!
But have you ever stopped to wonder what goes on when you ring your mates upon your mobile phone to talk about what time you'll meet up?

What drives this modern icon?
So, let's find out.

[Tony proceeds to smash phone with hammer.]

[Tony holds up old 'Motorola' phone followed by modern mobile.] You see, your mobile phone has lots of different parts.
So today we're going to look at the bits and pieces that have made it possible to shrink it from this, which is a mobile phone - to this.

So, what's in here? Well, what was in there?
Right. So there's all sorts of bits and pieces.
There's erm, a screen, right.
There's - somewhere, has it gone flying?

[Tony holds up individual components of phone.] Have I lost it? Oh no, here it is.
There's a battery. There were some buttons, right. And the circuit that drives them.

But most importantly there were these things. These here, these are silicon chips.
They've only been around for forty years, but they've caused a technological revolution.
You see before we had these silicon chips, these are the things that powered TVs and radios.
Does anyone know what they are, these things, what they're called? [Tony points at valves.]

You see when I was a kid, oh, we've a hand up here, what are they? [Vacuum tubes]. Vacuum tubes, more commonly known as valves and these valves powered radios and televisions and the difference between those and these is obvious, it's the size.
But they both need the same thing to work - electricity.

[Lightning flash/sound of thunder.]

[Archive photo of Michael Faraday on screen.] You see, electricity's everywhere. It's all around us, it's in our bodies.
Your thoughts are millions of electrical impulses, firing in your brain - and electricity was first understood in the nineteenth century.
People like Michael Faraday who gave the first Royal Institution Christmas Lectures in 1826 was experimenting with the very stuff in this room.

So, what is this magic called electricity?
It's the flow of energy and the energy is in little packets called electrons.

[Demonstration showing effect of 'arcing'.] You're going to see them - jumping - whoa!
And I don't like to get too close to that.
So electrons are jumping between those two balls. This is a really old machine that's been used in many, many Christmas lectures - thank you Bipin.

[Demonstration continues - a bulb is lit by electrons.] And here is another demonstration of electrons. These are in a plasma and they'll even light this bulb.
Can you see it light, as I come close?

The activity of those electrons makes this part of the bulb light up too.
So, what conducts electricity and what doesn't?

I'm going to need some volunteers to help me find out.
Yeah, so I'd like you to come down now, the volunteers.

[Volunteers make their way down.] So, what's your name? [Sukina].
Sukina, please to meet you Sukina, come here.
Now, this won't hurt, right. [Laughter]

[Children demonstrate conduction using various materials.] So there's a contact and there's a contact, right - and if we have conduction, the lights'll go up.
Do you know what this is? [Copper].
Right, let's have a go.
So I just want you to lean, lean it on.

Oh, and how many lights have gone on? All of 'em! [Yeah].
Wow, so that's a good conductor. You see, some materials are good at conducting electricity and some aren't. Why?
Well, if we look on the screen, you can see why. [Overhead screen shows children using balls to demonstrate copper passing on electrons.]
You see, in the copper, there are lots of electrons and they're floating around, so when a new electron comes in, the copper's happy to pass an electron on, because it knows it's going to get to keep one.

So, thank you very much. [Applause]

No, no, no, you two boys get to stay.
Right, what's your name. [Amari].
Amari, right, well let's take the copper off.
This is carbon. Do you want to put that on? You won't get a shock, I promise.
Oh, only two lights have come on. Do you think that's as good a conductor as the copper? [No].
OK, well thank you very much. [Applause]

This is a piece of polythene.
Right, what's your name? [Peter].
Peter, do you want to put it on, Peter and see what happens?
Are you sure it's on?

Yeah, no lights have come on, have they, because this is an insulator, it doesn't like to conduct.
You see, poor conductors, like this polythene, they have no spare electrons and what happens to them is when the electrons come in, they're greedy, they just grab hold of them and they won't let them go.
So that doesn't conduct electricity, so we've seen the difference now between conductors and insulators.

Thank you all very much. [Applause.]

[Tony demonstrates a simple circuit.] So here we have a simple circuit. You see the insulator's useful. It's got copper wire inside.

But it's got an insulator wrapped around the outside, so when I touch this copper wire, I don't get a shock, so you don't want to be touching live wires at all, because they'll give you a shock, so don't do that when you're at home, you have to be careful with electricity.

So in this simple circuit, I've got a source of electrons and when I make the circuit, by making this connection with a switch, the light comes on.
So the light comes on because the electrons are whizzing round this motorway made out of copper.
And then when they get to the light bulb, it's like going from the motorway onto Piccadilly.
They have to slow right down, put their brakes on and give some energy up and when they give their energy up, they give it up in the form of light.

[Tony holds up a mobile phone.] You see, I can use this on/off to send a signal.
My mobile phone is very sophisticated.
This sends signals, but we can use on/off, on/off to send simple signals.

So, let's say I've gone out climbing with my mates and we've got stuck up the mountain.
We don't know where we're going to get to, what's going to happen to us, we're running out of food, it's getting cold.
How can we signal to people that we're lost?
We've no mobile phone.
All we've got is a torch.
What can we do? [Morse code?]

Morse code, brilliant.
[Tony switches light on and off.] So we can go, dot, dot, dot, dash, dash, dash, dot, dot, dot.
And that was the first way of using electricity to send messages.
And now, hopefully, the rest of the lads who are down in the pub will come and rescue us.
So, you see Morse code is the predecessor of binary code.

[Table with 'string' of numbered lights is wheeled in.] So here I've got a string of lights. And each one of them can be on or off.

[Tony demonstrates by switching lights on and off.] And with these eight lights I can encode two hundred and fifty six numbers.
So if I want to encode zero, then I just have a whole string of offs.
If I want to encode one, then I just turn that light on and if I want to encode seventy-two, then I do sixty-four and eight.

Seventy-two in the binary code is zero, one, zero, zero one, zero, zero, zero, right.
And if I want the number four, then I only have this light on. Zero, zero, zero, zero, zero, one, zero, zero.
And if I want to encode two hundred and fifty-five, then, so when all the lights are on it goes one, one, one, one, one, one, one, one and that's the number two five five.

So this method of encoding information is actually very efficient, the binary code.

Professor Tony Ryan
[Tony holds up a valve.] Years ago, when I was a lad, right, electric circuits had their switching done by these big, bulky things.
They're very inefficient, these vacuum tubes that we know as valves. In fact you used to have to wait for the telly to warm up, but forty years ago, things started to change and the transistor was born.

[Black-and-white still picture of the first transistor on overhead screen.] There's a picture of the first transistor, it's a switch with no moving parts and to make a switch like this, you need to be able to change one of those insulators that we saw before into a conductor.

And I'm going to need some volunteers to help me do that. They were given hats on the way in, right, so put your hats on. Hats, hats, hats, there should be ten red hats and some blue hats. [Volunteers file down to the floor wearing blue and red hats.] Down you come, blue hats here, red hats there.
This is where semi-conductors come in.

[The overhead screen shows children demonstrating the process by using balls as electrons.] They don't have enough free electrons to be conductors, but if you start to put electrons in, there's a big enough field, then some of their electrons will be pushed off and they'll start to conduct.
So here they go, they've got a spare electron and they're passing it along.

Notice how slow it is compared to the conductor we saw earlier.
You see, semi-conductors control the flow of electrons through a circuit, so we're going to show you how that works.

[Volunteers are used to demonstrate transistor 'gate'.] Now you're the first electron in this chain, aren't you?
Right, so you're going to be knocking at the door, let me through, let me through.
OK, now we get the first person to come up, that's plenty of knocking, thank you.

I want you to come round this side, this side. Put your hands here.
So you're the first electron to come up to the gate.
Give it a push, can you open? No.

Next one, in you come.
Both of you need to push now.... I like that team, they're good.
Now push, no.
OK, last one.
Good, we've got a nice big electron for the end, right.

Have a quick knock on the door, knock, knock, knock, let me in, can we push?
Right number of electrons, the door opens and all the ones that were queueing up go through.

Now this revolutionised the radio industry, because transistor radios were born and they relied on a transistor to be an amplifier and we've just amplified three electrons into one, two, three, four, five, six, seven, eight, nine, ten, eleven electrons, or is it ten?
OK, it's ten - [laughter] - using this transistor.
Thank you all very much, thank you.[Applause.]

At the heart of your mobile phone there are these silicon chips and these are basically circuits connecting millions of transistors and these gates, just like the gate we saw control the flow of electrons.
In each bashed-up mobile phone there were ten million transistors.
That's as many as there are people in London.
[Shot of original transistor on overhead screen.] So how have we managed to go from this giant transistor, which is bigger than this mobile phone to something that's so small, we can't even see the transistors with the naked eye?

Well over here, this instrument is called an atomic force microscope. The transistors are so small that we can't see them with the naked eye. [Shot of transistors as seen through a microscope on overhead screen.] And this works like a blind man. So the way the microscope works is you put the transistors underneath and there's a tip that taps up and down and the sample, the silicon chip is moved underneath, so you can see the wafer being scanned in here and it's moving backwards and forwards and the tip's tapping up and down.[Tony taps stick on board to demonstrate tip tapping.]

[Close-up shot of the tip of the stick on the overhead screen.] Now the edge of the tip is an atom.
It's that pointy, you can't get pointier than an atom, right.
So as the wafer comes past, you see any differences in height, yeah, and effectively we image by the change in noise.

So here we can see an image.
This line is because the microscope's currently scanning.
It's taking this image live in the theatre. And this distance across here is the thickness of a human hair.
So there's all of this detail crammed on to the silicon chip.
So how do we process all of those tracks into something that's this complicated?

On here are the chips for a multitude of mobile phones and I'll show you how they do it.

[Tony demonstrates process using stencil and spray paint.] So, what you have to do is make a pattern.And then through that pattern change the silicon in the wafer from being an insulator into being a conductor.

So you have your pattern and your - spray.
Now industrially they have to develop the pattern and the pattern's written in a polymer.
So then what happens is you use that track and blast in new elements.
And those elements are often phosphorus and nitrogen.

So we can make a circuit just by doing printing.
You see we push elements into the silicon and lay down a path and that path can conduct electricity.
Electrons can flow. A real chip has millions of these tracks which make up the circuits.

So let's try it now. We've made the circuit and the lights come on, conducting through the track we made. Thank you Bipin. [Applause.]

[Series of graphics on overhead screen showing miniaturisation process.] At the moment, silicon chips are halving in size every eighteen months and the reason for this miniaturisation is our ability to make the gaps between the tracks smaller and smaller.

But there's a problem, we can't make the track any smaller than a single polymer molecule we use to make the pattern and at the current rate of progress, we'll hit that limit in about fifteen years time.

So for now we've seen the heart of the mobile phone and shortly we'll see all those parts come together to make it work. [Applause.]

[Tony rides into lecture theatre on battery-powered scooter.] So, we've looked at the heart of the mobile phone and how electricity's used to store and transmit information and in this part we're going to look at the source of this power.

Whoa-oh!
So, how many times have you been caught with the flashing low battery warning on your phone?
You're right in the middle of making a hot date and suddenly the power shuts off.

The hot date part doesn't happen to me very often.

But the phone going dead does, and it's not fair to blame the technology.
You see, today's modern phone battery is a miniaturised high tech piece of kit.
But it's basically the same as the first one and this is it, the world's first battery.

[Battery is wheeled in on table.] So, Bipin's going to help me by putting it together. [Close-up shot showing archive black-and-white drawing of Volta.] And it was made by an Italian, Alessandro Volta and it's a series of plates with something in between that's soaked in a liquid and - can you hear it start to fizz?

I can, and it smells shocking!
Right.
[Tony holds up £20 note showing Faraday on the face of the note.] You see, this man, Michael Faraday, he never made a great deal of money out of these phones, but he certainly got famous enough to be on our money for quite some time.

So, we're almost ready now. The last one goes on.

[Lecture theatre lights dim.] And the connection gets made.

[Battery light glows.] Stacks of different metals and a liquid, yeah. And Volta's batteries don't last very long.[Laughter.]

Thank you Bipin. [Applause.]

[Tony demonstrates 'lemon' batteries being used to a power calculator.] This calculator is powered by a battery made from a series of lemons.
Can you see the numbers? It works.
And I'm going to show you how it works now.

So, to make a battery, you need two different metals and they're called the electrodes.
And you put them in a liquid that conducts electricity.
That's called an electrolyte.
And on comes the clock.

Right, off it goes. I put the different metal in, on it comes.

This battery works the same way.
It has two different electrodes and something that conducts electricity.
And the problem with these is that they literally run out of juice. [Tony squeezes lemon.]

I like that joke! [Laughter]

OK, Bipin - now he came running in to stop me spoiling the floor, because this is Faraday's lecture theatre and the words 'electrolyte' and 'electrode' were invented in this building.
[Tony holds battery.] But these batteries tend to run out, because everything gets used up, they run out of juice.

So what we need is a way of making a battery that we can recharge.
So here I hope, is something that'll show us how we do a recharging.
And I'm going to need someone to come down and help me.

[Tony demonstrates system of recharging batteries.] So, this young man here. OK, what's your name? [Robert].
Robert, can you stand over there, Robert.Pleased to meet you.
Are you all right? Now you don't need to do anything yet.

So we have a yellow liquid and a blue liquid.
We're going to open the valve like it's a battery and they react and the wheel goes round and they become, after they've reacted, a green liquid.

So these batteries are very heavy, generally, like the scooter I came in on, seventy per cent of its weight is the battery.
It's like a milk float, it'll only do about five miles an hour.

So we'll close the valve now, right, and so you've gone home, this is like your mobile phone, you've plugged it in to recharge it and energy comes out of the plug in the form of electricity.

And that's what this pump is.
So let's pump the liquids back up. [Robert pumps liquids.] It needs a vigorous pumping action, yeah, and there they go, the green liquid disappears and the yellow and the blue reservoirs get refilled.
Thank you very much indeed.

Does your phone gurgle as much as that when you recharge it? [No].
Good, thank you. [Applause.]

Professor Tony Ryan
So what I'd like you all to do now is take out your mobile phone, if you've brought one and have a look inside at what the battery is.

This one, let me just read it. It's a rechargeable nickel metal hydride battery.
Who's got one of those? Right.
You've not got very good phones then, I'm afraid, right.
How about someone with a lithium iron battery?

Yeah, you've got a lithium iron battery, OK, you're going up market a bit, so are you.
And how about someone with a lithium polymer battery?

Wow!!
Lots of you, you've got better phones than me, they're the top of the tree and the power that they contain is because the technology's changed.
The liquid that conducts is no longer a liquid, it's a polymer and that allows us to cram a lot more power into a smaller space.

So don't put them away yet, but you can put the batteries back in.

So we've seen now how circuitry and batteries have become smaller and smaller.
So your mobile phone's shrinking in size.
But all of this technology would be absolutely useless if you couldn't interact with it - if you didn't have one of these screens.

So we need a display for the information. And it has to be small, it has to be light, so - this is heavy.
[Tony holds up a cathode ray TV tube.] Something like this which is the guts of a TV wouldn't be any good.

What we need is a liquid crystal display. And here's an example.
Now, to help me do this I need a short volunteer.

[Small girl volunteer squats down behind large LCD screen.] Oh, you look like you'll be a great volunteer for this one, right. What we need to do is bend down, so you can see this milky thing here.
Now you're not going to pull any faces, are you?!

You're not even going to stick your tongue out? [OK]. [Volunteer sticks tongue out.]

What a rude girl!

Right, what happened?
When I pressed this button, you can see through the screen and when I turn it off, you can't see through the screen.

Thank you very much for helping me. [Applause.]

You see the screen has something inside that sometimes is opaque and sometimes is clear and it's a liquid crystal molecule. [Tony catches ball which has been thrown from above.] And they are shaped like a rugby ball and they're sandwiched in between the two pieces of glass. You see, sometimes these liquids that are shaped like rugby balls are arranged at random and sometimes they all point in the same direction.

You see, we can line them up, using electricity.
And that's what happened when that screen switched on and off and to show you how this happens I need four more volunteers.

So we'll have you and you and you and you, thank you. [Laughter.] [Applause.]

You see, you guys, you're going to become the liquid crystal molecules. I'd like you to come over here, right.

If you stand just here and you come the other side of her - there you go, I want you to hold that, this is going to help you be a liquid crystal.
Right, you come here, hold that, I want you to hold them tight into your body and just move together.

Now, sometimes you point in one direction and then we put the electric field on and you turn that way and you become clear.
Now we can see the writing in between these liquid crystal molecules.

And then when we turn the field off, you turn back again. Marvellous!

I'll take these off you and say thank you very much indeed - [applause] - and you can go back to your seats.

But that display I showed you wasn't actually all that useful.
It went from being clear to being milky white.
And what you need in a liquid crystal display is something that goes from being transparent and appearing, let's say, white and opaque and appearing dark or black.

And the way that's done, in your phones is with something called a twisted nematic display.
It's a right mouthful, but they work really well.

[Tony puts on Polaroid sunglasses.] And they rely on polarisers, just like these, right.
So, we take something that we know from sunglasses, called a polariser.
So here's one here, right, it's a polariser - I'm just looking round, because I need someone to help and I need someone with a light coloured garment on, so actually this young lady here'll work fine, OK.

[Volunteer wearing white top is used as screen.] So I just need you to act as a screen, so if you turn this way, OK - so here's a polariser and here's another polariser and you can see through them.

If I rotate them, then they become opaque.
And now I have to put something in, no, you stay there, you're doing just fine - I have to put something in that messes with the polarisation of the light and this is it, so when we twist with an electric field, we can change the polarisation of the light by twisting and untwisting the liquid crystals.

So, thank you very much, we saw that quite clearly, I think. [Applause.]

So we've seen the technology that drives your mobile phone and we've literally changed the world of communication and in the next part, we'll look into the future.

So what will the communication of the future look like?

Professor Tony Ryan
As we've seen, there's little doubt that mobile phones have revolutionised our lives, but are they the end point of communication?
You've probably heard of 3G mobile phones, that you can watch videos and films on.
And this is one such phone, with a picture of a baby.

You see, we can have pictures like this on our current handsets, but we couldn't watch things that stream.
So now we need to explore the future of the communications technology.

You see, in silicon, we're approaching the limit.
Single polymer molecules define how wide we can write the tracks and maybe we need a more efficient way of processing and sending information.
And the answer to this is staring us in the face, it's light.

[Light fills the lecture theatre.]

You see, electricity isn't the fastest thing on the planet, light travels much more quickly, so why don't we use that instead?
If you wanted to phone George W. and say, can we talk about global warming or something, you'd use optics and under the ocean would be a cable like this, so this has rather than copper carrying the messages, it has these optical fibres.

[Close-up shot of optical fibres.] And these optical fibres are just like these.

When you make that phone call from your house, the first part of the message goes down copper and then at the exchange it's turned into light and it travels all the way to the USA, not as electrical pulses, but as light pulses and I'm going to show you how.

So here we have a wave guide and that's what the copper does, so here's your phone call as it goes down the cable.

... You can see it's a series of flashes - noughts and ones.
You see, on that journey ninety-nine per cent of the time is taken in the copper to go from your house to the exchange and less than one per cent of the time is taken in the optical cable going under the sea.

So how is it done?
Well Bipin's going to help me show you.
So all the messages and we showed you a red message, fire into the exchange, so they're all different colours and then they get mixed together and sent down the cable and they become white, because we've mixed all of the colours together. [Overhead screen shows 'white effect'.]

And then when we get to the other end, the colours are separated and they zoom under the sea at three hundred thousand kilometres a second and when they get there that light's converted back into electrical energy.
Thank you, Bipin.

And the same technology allows us to turn an image into electricity.
So here comes Jon with his digital camera for the ... picture, right.
[John takes picture of Tony standing in front of the jumbo mobile phone.]
So in there, in that optical train is a piece of electronics, a semi-conductor, that has pixels and those pixels convert the image into electrical signals.

Now we all know that light's a mixture of colours and each colour we perceive is a distinct wavelength, or frequency, a segment of the whole spectrum.

To carry the information around the world, the optical cables rely on light being split into more than just its basic seven colours.

Did you learn this at school? 'Richard of York gave battle in vain.' Yeah?
So that's for red, orange, yellow, green, blue, indigo, violet.

And they're the words we use to describe the colours, but if you have optics that are very good, you can break white light down into many, many more colours than that and that depends on their wave length.

So if we're going to move information around quickly on a phone network, why not apply the same principle when we build computers?
So if we do that, we need materials that'll allow us to manage the light in the same way that we made materials that'll allow us to manage electrons.

So if we're going to replace the silicon chip with a much faster optical chip, then we can literally process information at the speed of light, so there's a challenge in making materials that nature gets there first, every time.

[Tony holds up a frame with mounted blue butterfly.] So this beautiful butterfly appears to be blue.
Well actually we turn as we tilt the butterfly the colours start to change. It gets a deeper blue.
This butterfly's actually brown and it has a surface that's mottled such that it produces diffraction and you only see the blue.

So we need to be able to make materials that can control light and here's an example from Sheffield.

[Close-up shot of blue liquid in container.] So this is a brightly coloured liquid, right, you can see it's a liquid, because it's flowing and the colour comes from, not the fact that the molecules are coloured, but that it's manipulating the light.

So if we put a spoon of the liquid in the base here and squeeze down the top, we get something that's actually bright green.

Can you see the green colour?
That green colour came from that goopy looking liquid, because the liquid has layers in and those layers only reflect the green light.
You see, the future of communications technology is like this - managing light.
We could use this liquid to make tracks by printing, but this isn't the only technological breakthrough in mobile communications.

You see, when you got your mobile phone out and it had an LCD display, that's why the battery runs out, it consumes a lot of power and it consumes power in the back light, the thing that makes it - come on.

You see, what we need to do is use light emitting devices, light emitting diodes.
And we see them everywhere.
What they do is they convert electricity into pulses of light, just like this.

The first LED's were red, like this one and they were made from a compound of gallium and arsenic, called gallium arsenide.
Then came yellow LED's and eventually blue LED's and we need blue LED's and they're made from gallium nitride to make white and that's what held LED technology back.

When you mix the colours, red, blue and green, you can make white, just like we see in the middle of the screen now.

These LED's are much more efficient at transforming electricity into light than a bulb.

[Tony stands by set.] The future of displays and lighting is here. The power consumption's so low. Look over here at the set. Here is an array of LED's. There's lots of them and their power consumption, the amount of electricity needed to drive them is less than a bulb.

If we could convert every traffic light in the UK to work in an LED's we'd save enough electricity to power a large city and we'd have to put far less carbon dioxide into the atmosphere.

So LED's are the future, but really the future is LED's made from plastic, because it's cheap and disposable.
So these are actually light emitting polymers and they work in exactly the same way as the transistor.

So they emit light and the UK's a world leader in this technology and the roll-up TV is just around the corner. So what about things that take light and convert them into electricity?

[A large solar panel is carried into lecture theatre.] This solar panel is the current state of the art. And what this is, is a big LED running backwards, but you don't get that much power out of them and they're big and heavy, that's what it needs these two big lads!

Whereas, this device that's running this clock, this is a polymer LED.
It's made from plastic, so it's light.

And it's much, much better at converting the light into electricity.
If you're a cricket fan, you'll like this, if we could cover the area of Australia with photo voltaic cells with solar cells, then we could provide all of the world's energy needs, just from the sun.

And we'd never need to get beaten at cricket again! [Laughter.]

So - Annie's going to come on and put something into this oven.
You see, this phone has a digital camera inside.
It contains what's effectively a very complicated solar panel. It takes a light image and converts it into a stream of electrical noughts and ones.
The picture is made up of pixels and each of these pixels is a semi-conductor and they give out a different voltage depending on the light that hits them.

So, what we did earlier was we can transfer this digital image to make ourselves some mementos of this immensely successful lecture!

[Tony holds up T-shirt with picture taken earlier standing by jumbo mobile phone.] You see, I'm going to get a new T-shirt which has the picture we took earlier. And Annie's going to come and recover her mobile phone, which has had printed on it - yeah, the same picture. [Applause.]

Thanks Annie.
So these serve two purposes. Not only will they remind Annie and I of the lecture, but they also encapsulate all the things I've been talking about today.

To get this picture of me on this T-shirt and mobile phone cover, we've had to convert light into electrons and then those electrons into a binary code.

We've used that to make an image with dyes and then we've transferred those dyes onto this T-shirt and onto the phone back.
And they're transferred by diffusion, which is the way we made the tracks in the silicon trips and now your eyes are converting the light you receive from this image into electricity and your brain says 'he's holding up a T-shirt.'
Thank you.

[Applause/music/credits roll.]