[MUSIC PLAYING]
From the Royal Institution in London, DemoJam.
Featuring designer of particle accelerators, Suzie Sheehy.
Vision researcher and engineering
lecturer, Ben Craven.
Protein crystallographer, Stephen Curry.
The UK's coolest science teacher, Jonny Berliner.
And your host, formerly the UK's coolest teacher, now
stand-up mathematician, Matt Parker.
Are we done?
We're done.
All right.
Now, ever since we had DemoJam, well, this means the
Royal Institution is no longer just for Christmas.
Lectures?
Oh, no.
No, no.
We've invited our favourite scientists from right across
the country to come in, flop their favourite demos out on
the table, amaze us, educate us.
Whatever they're going to do, it's going to be thoroughly
good, geeky fun.
And to start us off, can we please put our hands together
for our very first DemoJammer, Dr. Suzie Sheehy.
You would have seen one of these Van de Graaff generators
when you were at school.
But if your school was anything like mine, then once
a year, the thing got hauled out, switched on, and
absolutely nothing happened.
Now, what's supposed to happen is that the belt peels
electrons off the rollers, and it builds up a positive static
charge on the top of the dome.
I've got a bunch of electrodes which are hooked up
to the Van de Graff.
And when I switch it on, every other electrode will become
positively charged.
And the rest of them will stay at ground, or zero volts.
And my particle today is a ping pong ball which I've
covered with a metallic paint so it can hold a charge.
And when that sits on one of the positive electrodes, it
becomes positively charged itself.
And you should have learned, around about the Van de Graaff
lesson in school, that like charges repel.
So it actually pushes away from the positive electrode.
And then, when it sits on the ground electrode, it loses all
of that charge and becomes neutral again.
But it keeps rolling across to the next positive electrode,
and the cycle repeats again.
And each time this happens, it gains a
little bit of momentum.
So it gets faster and faster and faster, if the Van de
Graaff works.
So, if you'll all do me a favour and just kind of will
it on with all of your will power, I'll just switch it on.
It's all right.
You can breathe again now.
Now, it turns out, you can't roll protons around in a salad
bowl, unfortunately.
You need to actually put them in an ultra-high vacuum and
then use magnetic fields to actually bend
them around in a circle.
Now, it also turns out that a real proton is about 200
trillion times smaller than a ping pong ball.
And it can't change its charge.
So we've made a bit of a cheat here, because we've kept the
electric field constant.
In a real accelerator, you have to change the electric
field to keep accelerating the particle around.
And you have to do it pretty quickly.
Because the protons in the Large Hadron Collider, well,
they're traveling at just a tiny fraction below
the speed of light.
And the speed of light is 299,792,458 meters a second.
So, keeping that in time with increasing speed of the
particles is pretty tricky.
And we're not just talking about one particle.
We actually accelerate billions or even trillions of
them all at the same time.
And they all have the same electric charge, so they all
try and repel against each other.
And trust me, that causes all sorts of other problems.
So, as models go, this one is a little bit simplified.
But there's two things about real accelerators that this
can actually show us.
The first one is looking at the shape of the bowl, the
curved shape, that's actually quite similar to the way we
shape the magnetic field in the type of
accelerator that I work on.
And if you guys want to google it later, it's called a
Nonlinear Non-scaling Fixed-Field Alternating
Gradient Accelerator.
Now the other thing which relates to real particle
accelerators is the power source.
Accelerators based on this Van de Graaff principle were
actually the cornerstone of nuclear physics
research for decades.
And my first publication, which was in nuclear physics,
used a Van de Graaff accelerator.
So to me, the Van de Graaff isn't just an unreliable,
useless classroom demonstration.
It's a reminder of how the development of particle
accelerator technology has fundamentally changed the way
that we understand the world around us.
Ladies and gentlemen, Dr. Suzie Sheehy!
[APPLAUSE]
That's fantastic.
We give you the Small Hadron colander.
Now, if you're at home watching this from the comfort
of your own computer, you might think that DemoJam,
well, you think it's a short, concise, fun evening.
Oh, no.
It's not.
We just edit it to make it look like it's short and fun.
In reality, the show takes lots of long, tedious breaks
while we set up for the next shot.
So to avoid the audience becoming too, well, irate, we
give them some busy work.
We're going to issue everyone with two Styrofoam cups and
some elastic bands, and we'll come back later in the show to
see what they're going to make of them.
Now, however, can we get ready for our next DemoJammer.
Put your hands together for Dr. Ben Craven.
[MUSIC PLAYS]
In a moment, down here, I'm going to show
you a little square.
And what I want you to do is to tell me, in one word, your
first impression, what colour that square is.
So here goes.
Call it out.
White.
OK.
So you think that one's white.
Well how about this one?
White.
Even whiter.
So maybe the first one is not as white as
you thought it was.
Well, if that second one is white, look at that one.
Okay.
That's really white.
And so white that we're having to adjust the camera to take
account of it.
So, do you think that third one is definitely white?
Yes.
Are you absolutely certain it's white?
Well, look.
There's the white one.
Now, see this first one you were looking at.
What color do you think that is now?
Grey.
It's grey, right?
Let's take the lights up and see what it really is.
What colour is it?
Black.
Now, a couple of minutes ago, you were telling me
that that was white.
Now you're telling me that it's black.
So let's see what's going on.
Let's have the lights back, please.
I was actually giving your brain a very, very difficult
task to do here.
This square is emitting a certain amount of
light into your eye.
Now you're in a dark room, and this is probably the brightest
thing you can see.
And so, your brain made the perfectly reasonable guess
that this was a light thing in a dark place.
But what the visual part of your brain didn't know about
was the very bright light inside the box.
And what it was actually looking at was a piece of wood
painted black in a very bright place.
I'm going to do a little survey now.
Has anybody seen this effect before, this demonstration?
A handful of people have. Most of you haven't.
Well I'm sorry to say that most of you are completely
wrong, because you've seen it hundreds of times before.
When you look up at the moon in the sky, it feels like
you're looking at a light object, a
light-coloured object.
We make jokes about the moon being made of cheese.
In fact, if I had a piece of moon rock
here, it would be dark.
It would be something like the surface of a road or a piece
of dark slate.
When you look at the moon, you're not looking at a light
object in a dark place.
You're looking at a dark object in a very bright place.
Because the sun is shining very brightly on the moon.
So next time you look up at the moon in the sky, I want
you to try and convince yourself that you really are
looking at a dark object in a bright place.
I've been trying for years, and I've never succeeded.
So I hope you'll have better luck than I do.
Thank you.
[APPLAUSE]
[MUSIC PLAYS]
Wow, that really is mind boggling.
And, actually, do you mind if we have a look?
if you come in here, right, you can see.
It really is that there's a bathroom light and then just
some poorly painted bits of wood.
That is absolutely brilliant.
And thankfully, because of this bit of equipment, we now
finally have scientific proof of the Jackson conjecture,
which states, it don't matter if you're black or white or
some kind of intermediate stage.
Anyway.
Now DemoJam would like to welcome along Professor
Stephen Curry for a little fireside chat.
[APPLAUSE]
[MUSIC PLAYS]
For which I need to be over there.
And now I'm over here.
I'm joined by Professor Stephen Curry, who is a
structural biologist. And you work on the somewhat dangerous
foot and mouth virus.
Yes.
That's right.
And that does sound very dangerous.
Do you actually get to use the virus?
No, I work in a laboratory in London.
We are not allowed, by law, to use the virus because it's so
contagious.
And we only work on small fragments from the virus.
So you get, like, a little bit?
We do, yes.
Like, just the foot?
Not quite the foot, but we work on proteins that the
virus makes inside the cell during
the course of infection.
OK, OK.
So you get a safe bit to look at.
It's entirely safe.
You've brought in a virus.
And we couldn't bring in foot and mouth, I'm afraid.
But here we have, now, who is this guy?
Well, this is actually a kissing cousin of foot and
mouth disease virus.
This is actually the human rhino virus, which causes the
common cold.
That's the common cold.
Right.
Now, how accurate is this model?
Well, this is a child's toy.
So it's not entirely accurate.
The real virus has no eyes, is not covered in soft blue fur.
It's nowhere near as adorable.
I'm afraid not.
But it is still an educational aid to some extent, right?
It is.
There is one feature which is quite anatomically correct.
And that you can see on this end of the virus, which is
that it has a five-fold symmetry axis, which means
that if we rotate it 1/5 of a turn, then the
virus looks the same.
How do we actually know any of that?
I mean, how do we know it's shaped like an icosahedron?
Well, that's a good question.
Because this toy is actually quite a bit bigger than the
real thing.
In fact, it's about 3 million times larger than
a real rhino virus.
That's not bad.
That's better than the proton we had.
Indeed.
But even so, it's too small to see by eye, and it's too small
even to see with our very best light microscopes.
You can get a fuzzy image with an electron microscope, but if
you really want to see the atomic details, which is what
I'm interested in, then you have to use a technique called
X-ray crystallography.
And for X-ray crystallography, you need X-rays
and you need a crystal.
I happen to have a crystal -
It's all there in the title...
- here.
Oh, yes.
So, this is a crystal of quartz.
So it's not a crystal of rhino virus.
You are all perfectly safe.
And what's interesting about a crystal is that inside the
crystal, all the atoms are lined up in orderly rows.
But the virus is not a cuddly toy, but it's not a crystal
either, is it?
No, it's not.
But if we grow up a few milligrams of rhino virus,
there are techniques which will allow us to induce them
to stick together in an orderly form that makes a
crystal of rhino viruses.
Right, so you get crystallized virus.
Yep.
And then the fun begins.
Yes.
So, a crystallized rhino virus would actually be an awful lot
smaller than this.
But the interesting thing about the crystalline form of
matter is that if you shine X-rays through it, then it
diffracts that X-ray off in hundreds of different
directions.
So you put X-rays through the lattice.
They get diffracted.
And you get your diffraction pattern, over
on a screen or something.
That's right.
And then, that's not a picture of the structure, but you can
work back, I believe, mathematically, from the
structure that you see here to the atoms that must have
caused that.
Yes, that's right.
So, we get spots on a detector.
But in those spots is all the information we need, thanks to
Fourier's transform, to reconstruct -
I'm a big fan.
- To reconstruct the structure of the virus.
And what's interesting about that is that Fourier was a
French mathematician from the nineteenth century.
He died, unfortunately, before the X-ray was even discovered,
before the virus was even discovered.
Why was he doing it?
Because he was interested in the transport of heat.
He was interested in how fast does it take heat to get from
one end of a hot poker to the other?
Hot poker research.
Right, now.
You do all this.
You do the X-ray diffraction.
You work back.
You get the structure.
Now, I assume we're using that to somehow
combat these viruses.
Yes.
So, if we can see the detail structure, so the results we
get are much more detailed than this.
We can see where every atom is in the virus, and that gives
us a really detailed understanding of how the virus
interacts with the cell, how it uncoats, and the things
that it does inside a cell to cause infection.
So if you understand how the virus works, then it gives you
a way to develop drugs in order to stop it.
So why have we not got a cure to the common cold?
Well, the common cold, fortunately for us, isn't a
terribly serious disease -
It is for me.
- By the time you develop symptoms, you're more or less
halfway on the way to a cure.
So you're going to get better anyway.
That's right, yes.
So all we get from knowing the structure of the common cold
viruses is we can make slightly accurate toys.
So if I -
You could say that, yes.
If you get ill, you can curl up in bed and cuddle the virus
that is currently infecting you.
That's just great.
Anyway, all the best with foot and mouth,
which is a great sentence.
Can we have a final round of applause for Stephen Curry?
[APPLAUSE]
Right.
Now that we're pretty much at the end of DemoJam, we should
check back in with our audience to see what they did
with those cups.
So they all have made Bernoulli cups out of them.
So let's see how this goes.
Spectacular, it turns out.
If you're wondering how to make your own Bernoulli cup at
home, then beneath me somewhere is an information
box which you've already clicked.
You can find out how to build your own, successfully.
However, given that this is the scientific process, we
need to end properly with a conclusion.
And because we are the Royal Institution here, we should do
it in an orthodox,
scientifically accurate method.
Which is, of course, through song.
Ladies and gentleman, Jonny Berliner.
[MUSIC BEGINS]
When I look at the world, it's all black and white.
Like the black of the sky and the white
of the moon at night.
But it's more than the wavelength of the ray that
gives me sight.
It's the way that my brain interprets the light.
But the colour of the moon's not black or white.
It's in between.
And it's a matter of psychology why
it couldn't be seen.
It couldn't be seen.
No, the colour of the moon, it couldn't be seen.
I got a cold.
It hurt a lot.
I wanted to see the rhino virus that
was causing the snot.
Looked under a microscope.
Nothing to see.
So I tried my hand at crystallography.
Got a pattern of dots.
Didn't know what they mean without Fourier analysis, the
icosahedron couldn't be seen.
It couldn't be seen.
No, the icosahedral structure of the rhino virus, it
couldn't be seen.
[MUSIC PLAYS]
Now Mr. Van de Graaff would be overjoyed to see his machine
spin a ping pong ball around a custom blown
acrylic oblate spheroid.
He'd be even happier that his technology can generate the
protons for the LHC.
That we accelerate and collide with energy and find
fundamental particles that couldn't be seen.
They couldn't be seen.
No, the fundamental particles, they couldn't be seen.
They couldn't be seen.
Jonny Berliner!
And that, ladies and gentlemen, is DemoJam.