0:00:02 > 0:00:04Scientists have been giving lectures in this theatre
0:00:04 > 0:00:07for nearly 200 years, but 80 years ago, almost to the day,
0:00:07 > 0:00:09something special happened.
0:00:11 > 0:00:15Lecture one, The World Of Captain Gulliver.
0:00:15 > 0:00:19The BBC transmitted a Christmas Lecture
0:00:19 > 0:00:23using a brand-new technology - television.
0:00:23 > 0:00:27- Thank you.- Science TV was born.
0:00:28 > 0:00:32So, to celebrate, we're recreating famous demonstrations
0:00:32 > 0:00:38and inviting Christmas Lecturers past to the stage to help out.
0:00:38 > 0:00:41The subject of these lectures goes back
0:00:41 > 0:00:44to their founder, Michael Faraday.
0:00:44 > 0:00:50It governs everything we do, from the nuclear furnace in the sun...
0:00:52 > 0:00:55..to the daily school run.
0:00:55 > 0:00:58It makes the whole universe tick
0:00:58 > 0:01:02and getting enough of it is one of the biggest challenges
0:01:02 > 0:01:08facing the whole human race. That subject is energy.
0:01:08 > 0:01:12Welcome to the 2016 80th Anniversary Christmas Lectures.
0:01:12 > 0:01:14APPLAUSE
0:01:35 > 0:01:39This lecture theatre consumes a huge amount of energy.
0:01:39 > 0:01:41We've got the lights,
0:01:41 > 0:01:45we've got the cameras and we've got some air conditioning, too.
0:01:45 > 0:01:48They're all energy guzzlers.
0:01:48 > 0:01:51We can see on our giant meter here...
0:01:51 > 0:01:55So this is no ordinary energy meter.
0:01:55 > 0:01:59We wanted to show you units of energy in a slightly different way.
0:01:59 > 0:02:02We're using AA batteries.
0:02:02 > 0:02:05So, how much do we need for this lecture theatre?
0:02:05 > 0:02:09So, running these lecture theatres requires...
0:02:09 > 0:02:1521,567 AA batteries.
0:02:16 > 0:02:19When I pull this lever here,
0:02:19 > 0:02:23all of that will be turned off.
0:02:23 > 0:02:25So tonight's challenge is,
0:02:25 > 0:02:29can we generate enough energy to power this lecture theatre?
0:02:29 > 0:02:35So along the way, I want to show you the amazing thing called energy.
0:02:35 > 0:02:37So, let's do a countdown.
0:02:37 > 0:02:41ALL: Three, two, one.
0:02:47 > 0:02:52So, this small candle is a good place to start.
0:02:52 > 0:02:56One of the greatest scientists, Michael Faraday,
0:02:56 > 0:02:58worked here at the Royal Institution.
0:02:58 > 0:03:03He gave Christmas Lectures on the chemistry of candles in this theatre
0:03:03 > 0:03:09around 150 years ago, and this is one of his favourite demonstrations,
0:03:09 > 0:03:11which I'm going to try and repeat.
0:03:11 > 0:03:15It's basically, can I relight that candle
0:03:15 > 0:03:18when I put it out without touching the wick?
0:03:18 > 0:03:20It's a bit tricky, but I'll try.
0:03:20 > 0:03:22OK. So...
0:03:22 > 0:03:24let's see.
0:03:29 > 0:03:32OK. You might have missed that - that was very quick -
0:03:32 > 0:03:35but fortunately we have that in slow motion.
0:03:35 > 0:03:37So let's see that in slow motion.
0:03:37 > 0:03:41So you can see the vapour there - that's the vapour -
0:03:41 > 0:03:43and it's going to relight...
0:03:45 > 0:03:48And look at that, it's going to relight the flame.
0:03:48 > 0:03:49So, what's happening there?
0:03:49 > 0:03:52Well, when you think of a candle,
0:03:52 > 0:03:56you think that actually it's the wick that's burning.
0:03:56 > 0:03:58That's not quite right.
0:03:58 > 0:04:03What's happening is that the wax vapour comes up off the candle
0:04:03 > 0:04:06and that is the chemical store.
0:04:06 > 0:04:08And if you time it right,
0:04:08 > 0:04:12you can actually relight the candle without touching the wick,
0:04:12 > 0:04:14as you saw in slow motion.
0:04:14 > 0:04:19So, it looks as if the wick is burning, but it's not, it's the wax.
0:04:19 > 0:04:22And the wax, as I said, is a great energy store.
0:04:22 > 0:04:27And this tells us a very important thing, a principle about energy -
0:04:27 > 0:04:31energy can never be created nor destroyed,
0:04:31 > 0:04:35it only converts from one form to another.
0:04:35 > 0:04:38In this case, the candle is converting
0:04:38 > 0:04:45the chemical energy in the wax to light and heat.
0:04:45 > 0:04:47There's another important principle.
0:04:49 > 0:04:54When energy is converted, we can actually use it to do work.
0:04:54 > 0:05:00And a simple example is again using this candle and a fan.
0:05:00 > 0:05:03OK, so...
0:05:07 > 0:05:10So if you see that, you can see that it's turning.
0:05:10 > 0:05:12So what's happening here is that the heat
0:05:12 > 0:05:15from the candle is rotating this fan.
0:05:15 > 0:05:21In fact, one definition of energy is the ability to do work.
0:05:21 > 0:05:25So, let's get back to our energy meter.
0:05:25 > 0:05:28How does the candle score?
0:05:28 > 0:05:32So, remember, to power our lecture theatre, we need to get up here.
0:05:32 > 0:05:34So, what does candle give us?
0:05:34 > 0:05:35OK, so we're going to see.
0:05:35 > 0:05:38It's going to drop down, drop down...
0:05:39 > 0:05:43OK. 31 AA batteries.
0:05:43 > 0:05:45Actually, it's more than I expected.
0:05:45 > 0:05:49We can see it's not going to be enough to power this lecture theatre.
0:05:49 > 0:05:54So we can scale up a candle to make it more powerful.
0:05:54 > 0:05:56OK, so...
0:05:56 > 0:05:58What we're coming on now...
0:05:58 > 0:06:01It's a very special candle.
0:06:01 > 0:06:04It's made of something called guncotton,
0:06:04 > 0:06:07which you can't get in the shops.
0:06:07 > 0:06:12OK? We're going to see if it's different from the earlier candle.
0:06:13 > 0:06:16Let's see how it does.
0:06:20 > 0:06:22AUDIENCE GASPS
0:06:26 > 0:06:28APPLAUSE
0:06:35 > 0:06:38Right, fortunately - I'm sure you all saw that -
0:06:38 > 0:06:40but what I love to see is in slow motion.
0:06:40 > 0:06:42OK, so we've got it in slow motion.
0:06:42 > 0:06:44So, let's have a look over here.
0:06:44 > 0:06:49So you can see there's the candle there, there's my long wick,
0:06:49 > 0:06:51and there you go.
0:06:53 > 0:06:57So, you might think that this candle has a lot more energy
0:06:57 > 0:06:59than that small candle over there.
0:06:59 > 0:07:03Actually, the difference isn't that much.
0:07:03 > 0:07:07And the reason is, the main difference is to do with power.
0:07:07 > 0:07:11Scientists are very careful about these two words.
0:07:11 > 0:07:15They want to distinguish the words power and energy.
0:07:15 > 0:07:19While both candles have about the same amount of energy,
0:07:19 > 0:07:22the guncotton candle, the one I just burnt,
0:07:22 > 0:07:24releases that energy all at once.
0:07:24 > 0:07:27It's a lot more powerful.
0:07:27 > 0:07:33So, power is simply how fast energy is transferred.
0:07:33 > 0:07:39So, I've already shown you that a candle stores chemical energy
0:07:39 > 0:07:42and it turns it into light and heat.
0:07:42 > 0:07:48But energy comes in loads of other different and amazing forms,
0:07:48 > 0:07:50and to help me explain this,
0:07:50 > 0:07:56it's a great pleasure to introduce a former Christmas Lecturer -
0:07:56 > 0:07:58Professor Richard Dawkins.
0:07:58 > 0:08:00APPLAUSE
0:08:03 > 0:08:04Hi there, Richard.
0:08:04 > 0:08:06Good to see you.
0:08:13 > 0:08:16Richard, it's a great pleasure and I'm glad you could join us
0:08:16 > 0:08:18for this 80th Anniversary Lecture.
0:08:18 > 0:08:24You did an experiment that I really enjoyed watching about 25 years ago,
0:08:24 > 0:08:28back in 1991, and we've got a clip here.
0:08:28 > 0:08:31I'm going to stand here and I'm going to release it,
0:08:31 > 0:08:34and it's going to come... It's going to go over there,
0:08:34 > 0:08:36and it's going to come roaring back towards me,
0:08:36 > 0:08:40and all my instincts are going to tell me to run for it.
0:08:40 > 0:08:44The whole principle is you can't gain energy,
0:08:44 > 0:08:47so it should swing back roughly to its original position.
0:08:47 > 0:08:49It can't go any further.
0:08:49 > 0:08:52But what do you remember about that experiment
0:08:52 > 0:08:54and why did you want to do it?
0:08:54 > 0:08:57Well, I think you're interested in conservation of energy.
0:08:57 > 0:09:00I was interested in showing my faith in science itself.
0:09:00 > 0:09:04As it were, putting if not my life on the line, my head on the line.
0:09:04 > 0:09:06So we're going to try and recreate it,
0:09:06 > 0:09:08but I have a confession, Richard.
0:09:08 > 0:09:13We have made a bit of a difference to the cannonball.
0:09:14 > 0:09:16We've added spikes.
0:09:16 > 0:09:21So we've put a bit of a target here and we're going to make sure
0:09:21 > 0:09:25it allows you to actually position your head perfectly.
0:09:25 > 0:09:29Right, so, we're going to have a bit of a drumroll this time.
0:09:29 > 0:09:31AUDIENCE DRUMROLLS
0:09:37 > 0:09:39Yes!
0:09:39 > 0:09:41APPLAUSE
0:09:48 > 0:09:51What I said last time was that I felt the wind of it and I did again
0:09:51 > 0:09:55this time, but I was told by Robert May,
0:09:55 > 0:09:58a very distinguished Australian scientist, that in Australia,
0:09:58 > 0:10:00when real men do that demonstration,
0:10:00 > 0:10:04they don't hold the cannonball to their head, they hold it down there.
0:10:04 > 0:10:06LAUGHTER
0:10:06 > 0:10:07- Thank you, Richard.- OK.
0:10:07 > 0:10:10Let's thank Professor Richard Dawkins once again.
0:10:10 > 0:10:13APPLAUSE Thank you, Richard.
0:10:21 > 0:10:27That swinging ball shows that you can't destroy or create energy,
0:10:27 > 0:10:31but you can convert it from one form to another.
0:10:31 > 0:10:35So, energy comes in lots and lots of different forms and I want to give
0:10:35 > 0:10:38you... I didn't want to give you a long, boring list,
0:10:38 > 0:10:42so instead I thought we'd do something a bit more fun
0:10:42 > 0:10:44and this contraption
0:10:44 > 0:10:48right behind me is called a Rube Goldberg machine,
0:10:48 > 0:10:52and it's been painstakingly put together by my Royal Institution
0:10:52 > 0:10:55team over the last month or so.
0:10:55 > 0:11:03And it's a type of energy cascade and carries on outside this theatre.
0:11:03 > 0:11:07So, I need a volunteer from this side over here.
0:11:07 > 0:11:10OK, I'll rush over.
0:11:10 > 0:11:14OK, so, could you come over here?
0:11:14 > 0:11:15So, can I take your name first?
0:11:15 > 0:11:18- Sophie.- Sophie, why don't you come on this side?
0:11:18 > 0:11:20So, let's take a seat there.
0:11:20 > 0:11:23We'll sit together. So, Sophie,
0:11:23 > 0:11:27what you're going to do is you're going to help me set off this
0:11:27 > 0:11:33Rube Goldberg machine by something I prepared earlier - this lovely ball.
0:11:33 > 0:11:37So if you just hold on to that and I'd like you to spot how many times
0:11:37 > 0:11:41energy changes from one form to another, OK?
0:11:41 > 0:11:43So we need a big countdown for this, OK?
0:11:43 > 0:11:45Give me a big countdown.
0:11:45 > 0:11:48ALL: Three, two, one.
0:11:48 > 0:11:51It goes. It's going fast.
0:11:54 > 0:11:58So, that is Jacob's Ladder with sparks.
0:11:58 > 0:12:00We've got the fan going off.
0:12:00 > 0:12:05We've got, hopefully, a little boat moving.
0:12:05 > 0:12:08Now, let's see.
0:12:08 > 0:12:10Amazing!
0:12:10 > 0:12:12OK? Let's see what's going to...
0:12:12 > 0:12:14It's going to go out of the lecture theatre.
0:12:14 > 0:12:17Here it goes. So look out for those conversions.
0:12:19 > 0:12:23OK, it knocks out... There's some kinetic energy.
0:12:23 > 0:12:25Elastic energy.
0:12:25 > 0:12:29Look at that. Down the corridor down there.
0:12:33 > 0:12:37There goes the car.
0:12:37 > 0:12:39Oh, the domino effect.
0:12:39 > 0:12:42This is one of my favourite bits, the wave.
0:12:42 > 0:12:44That's the wave there.
0:12:49 > 0:12:51So, plasma ball.
0:12:54 > 0:12:59This is a chemical reaction producing a fluorescent material.
0:12:59 > 0:13:03If you watch, it's going to go down this...
0:13:03 > 0:13:05circular wire. Look at that.
0:13:09 > 0:13:11And then...
0:13:14 > 0:13:18So, if you see, it's going to turn this bicycle wheel.
0:13:23 > 0:13:26And then it's going to pass that -
0:13:26 > 0:13:29that was a magnetic track.
0:13:34 > 0:13:37OK, let's see what's going to happen next.
0:13:37 > 0:13:40So, you can watch out for another chemical reaction.
0:13:47 > 0:13:49So this is out the side.
0:13:49 > 0:13:51It's going to knock over those balls.
0:13:51 > 0:13:53Hopefully it will set off...
0:13:55 > 0:13:59..that ball. It's going to come back, hopefully, very soon,
0:13:59 > 0:14:01through the corridor, through here.
0:14:01 > 0:14:04Back into here. Watch out for it.
0:14:08 > 0:14:10Yeah!
0:14:10 > 0:14:12APPLAUSE
0:14:19 > 0:14:21Yes...
0:14:21 > 0:14:23HE LAUGHS
0:14:23 > 0:14:27So, I gave you a test, or exam, at the beginning of that,
0:14:27 > 0:14:30in the number of energy conversions.
0:14:30 > 0:14:33So, does anybody have a guess of how many there were?
0:14:33 > 0:14:35Anybody shout out a number?
0:14:35 > 0:14:3815?
0:14:38 > 0:14:4120? So, who's going to go for 15?
0:14:41 > 0:14:43Who's going to go for 20?
0:14:43 > 0:14:45Who's going to go for a lot more?
0:14:45 > 0:14:49Well, the actual answer that we worked out
0:14:49 > 0:14:55was roughly about 111 different energy conversions.
0:14:55 > 0:14:56So...
0:14:56 > 0:15:00When we think about energy in our daily lives,
0:15:00 > 0:15:06we often think about one thing, and that's electricity.
0:15:06 > 0:15:10But we don't often see electricity in the raw,
0:15:10 > 0:15:13so I want to make electricity a bit more visible.
0:15:13 > 0:15:19So, could you please welcome Derek Woodroffe, electricity expert?
0:15:25 > 0:15:28I'll go around that side.
0:15:29 > 0:15:31Nice to see you, Derek.
0:15:31 > 0:15:34I love your contraptions here.
0:15:34 > 0:15:37I know they're two separate Tesla coils.
0:15:37 > 0:15:41They make people here at the Royal Institution a bit nervous.
0:15:41 > 0:15:45The last time they had a Tesla coil here in this lecture theatre,
0:15:45 > 0:15:50it fried all the fuses and it turned all the computer text German.
0:15:50 > 0:15:51LAUGHTER
0:15:51 > 0:15:54But these two Tesla coils are different.
0:15:54 > 0:15:57They've actually learned to play music, German music.
0:15:57 > 0:15:59So, Derek, take us away.
0:15:59 > 0:16:01If you could dim the lights as well.
0:16:01 > 0:16:03MUSIC PLAYS
0:16:09 > 0:16:11APPLAUSE
0:16:18 > 0:16:22Right, so what you've seen there is basically a flow of electrons.
0:16:22 > 0:16:24Electrons carry charge.
0:16:24 > 0:16:29So these Tesla coils build up a huge amount of electrons,
0:16:29 > 0:16:33or negative charge. There's such a big build-up of electrical charge
0:16:33 > 0:16:38it's released in a single burst of electricity, or spark,
0:16:38 > 0:16:41that turns air into a conductor.
0:16:41 > 0:16:44And where else do we see this?
0:16:44 > 0:16:47Well, as you can imagine, it's lightning.
0:16:47 > 0:16:51During pretty violent thunderstorms, you get that big build-up of charge.
0:16:51 > 0:16:54So, why are these ones a bit musical?
0:16:54 > 0:16:58Well, changing the frequency of the sparks means that these Tesla coils
0:16:58 > 0:17:00can play different notes.
0:17:00 > 0:17:04So I think we want to hear one more.
0:17:05 > 0:17:07HIGH-PITCHED MUSIC PLAYS
0:17:16 > 0:17:18LAUGHTER AND APPLAUSE
0:17:23 > 0:17:25Thank you, Derek.
0:17:25 > 0:17:27- Pleasure.- And auf Wiedersehen.
0:17:27 > 0:17:28DEREK LAUGHS
0:17:28 > 0:17:30OK, so let's get back to electricity.
0:17:30 > 0:17:36Electrons always take the fastest route to where they want to go.
0:17:36 > 0:17:41Travelling through the air isn't easy for an electron.
0:17:41 > 0:17:45In contrast, travelling through metal is a lot easier.
0:17:45 > 0:17:49So if you create a metal pathway for the electrons,
0:17:49 > 0:17:51they should always follow it.
0:17:51 > 0:17:53I wanted to test this out,
0:17:53 > 0:17:58so I sent Christmas Lecturer Professor Monica Grady
0:17:58 > 0:18:01to the biggest Tesla coil we could find.
0:18:01 > 0:18:04Hello, Monica, over to you.
0:18:04 > 0:18:08Hi, Saiful, hi, everybody, and look what I've got here.
0:18:08 > 0:18:12It's a Tesla coil and it's much more powerful
0:18:12 > 0:18:15than the one you've seen operating already.
0:18:15 > 0:18:20I am going to get into this Faraday cage here.
0:18:20 > 0:18:23Now, a Faraday cage is named after Michael Faraday
0:18:23 > 0:18:25of Royal Institution fame.
0:18:25 > 0:18:29How it works is the current passes across the wire
0:18:29 > 0:18:33and it doesn't go into the cage.
0:18:33 > 0:18:37So I will be quite safe sitting in there,
0:18:37 > 0:18:40but I'm still going to wear my wellingtons when I get inside,
0:18:40 > 0:18:42just in case.
0:18:49 > 0:18:52Right, well, I'm going to be locked in in a minute.
0:18:52 > 0:18:55It does feel a bit bizarre.
0:18:55 > 0:18:57But what I've got here is I've got a safety pad,
0:18:57 > 0:18:59and that goes under my foot.
0:19:00 > 0:19:05And while my foot is on it, the discharge will work.
0:19:05 > 0:19:08As soon as I take my foot off, everything stops.
0:19:08 > 0:19:11That's part of the safety apparatus.
0:19:11 > 0:19:13I've been instructed not
0:19:13 > 0:19:16to try to put my finger through any of the holes,
0:19:16 > 0:19:20definitely not to touch the wire and, just for once in my life,
0:19:20 > 0:19:23I'm going to be very, very, very obedient.
0:19:27 > 0:19:29Don't like this.
0:19:29 > 0:19:32I think it's better if we get it over with soon.
0:19:36 > 0:19:39So, take it away, Colin.
0:20:21 > 0:20:24Wow, that was stupendous!
0:20:24 > 0:20:26It's one of the really bizarrest
0:20:26 > 0:20:29experiences I've ever had.
0:20:29 > 0:20:31It was just really, really strange.
0:20:31 > 0:20:33And I never felt a thing!
0:20:34 > 0:20:36APPLAUSE
0:20:40 > 0:20:43I have to thank Monica - rather her than me!
0:20:43 > 0:20:45If you don't know about the science,
0:20:45 > 0:20:48you might think that this was very dangerous.
0:20:48 > 0:20:53I can safely predict that you've all been inside a Faraday cage.
0:20:53 > 0:20:55All the metal cars
0:20:55 > 0:21:00that you've driven in or been in, they are Faraday cages.
0:21:00 > 0:21:04That's good to know if you've ever been in thunderstorms.
0:21:04 > 0:21:07So, these Tesla coils have been great,
0:21:07 > 0:21:10but the electricity they produce is just an uncontrolled burst,
0:21:10 > 0:21:12an uncontrolled spark.
0:21:12 > 0:21:17So what we need is a smooth, steady flow of electrons,
0:21:17 > 0:21:21so we're going to have to find another way to power our theatre.
0:21:21 > 0:21:24We need an electrical generator.
0:21:24 > 0:21:28So, this brings us back to Michael Faraday,
0:21:28 > 0:21:31the founder of the Christmas Lectures, and, actually,
0:21:31 > 0:21:34he's one of my scientific heroes.
0:21:34 > 0:21:38He came from very humble beginnings rather than the wealthy elite,
0:21:38 > 0:21:40but he went on to discover a huge amount
0:21:40 > 0:21:43about the fundamental nature of electricity.
0:21:45 > 0:21:51So, one of his inventions was this strange contraption coming in here.
0:21:51 > 0:21:56It may look a bit like a burnt sausage...
0:21:57 > 0:22:02..but actually, this is one of the treasures of the Royal Institution.
0:22:02 > 0:22:05And our curator, Charlotte - thank you, Charlotte, for coming in -
0:22:05 > 0:22:06is going to hold it for me.
0:22:06 > 0:22:11I'm not allowed to touch it. So, believe it or not, this thing here,
0:22:11 > 0:22:16this tiny machine, totally transformed the way we live.
0:22:16 > 0:22:19It was the spark that ignited the electric revolution
0:22:19 > 0:22:23and it's really the first electrical generator.
0:22:23 > 0:22:25So, how does it work?
0:22:25 > 0:22:29Well, what it's made up of is it's got this metal, magnetic rod,
0:22:29 > 0:22:33as you can see there, and it's actually covered
0:22:33 > 0:22:35by these copper wires.
0:22:35 > 0:22:40And as you move the metal rod in and out through there...
0:22:41 > 0:22:47..that magnetic energy and that movement generates electricity.
0:22:47 > 0:22:49So it's an energy conversion.
0:22:49 > 0:22:55So machines based on this simple contraption power the modern world.
0:22:55 > 0:22:57So, thank you, Charlotte.
0:22:58 > 0:23:01So, how does a modern electrical generator work?
0:23:01 > 0:23:04So let me show you
0:23:04 > 0:23:07through this contraption here.
0:23:07 > 0:23:10So, before, that... The one that Charlotte brought in
0:23:10 > 0:23:14was a static ring where the metal rod went in and out.
0:23:14 > 0:23:18Here, and if the cameras can get close,
0:23:18 > 0:23:22you can see now we've got these copper wires again,
0:23:22 > 0:23:26but this time the magnet is rotating.
0:23:26 > 0:23:28I'll show you it slowly first.
0:23:28 > 0:23:30You can see the red and the greys.
0:23:30 > 0:23:33So let's rotate. But if you spin it fast...
0:23:36 > 0:23:41..you can actually begin to generate electricity by that magnetic energy
0:23:41 > 0:23:44and that movement. And since it's moving continuously,
0:23:44 > 0:23:47it's much faster, it's much more powerful.
0:23:47 > 0:23:52So, this is the basis of almost all modern electricity generation.
0:23:52 > 0:23:57But I'm not muscular enough to actually turn this, so I need
0:23:57 > 0:23:59somebody a bit more muscular.
0:23:59 > 0:24:02I need a volunteer.
0:24:02 > 0:24:03So, the one in green.
0:24:03 > 0:24:05Yes. Come on down.
0:24:05 > 0:24:07APPLAUSE
0:24:07 > 0:24:10Hello, there. Can I take your name first?
0:24:10 > 0:24:13- Daniel.- Daniel. Well, thanks for coming down.
0:24:13 > 0:24:18What I'm going to try and get you to do is that we've got some lights
0:24:18 > 0:24:19here, so don't start yet.
0:24:19 > 0:24:24We've got some lights here and by turning on each one,
0:24:24 > 0:24:27it kind of increases what's called the load,
0:24:27 > 0:24:29it kind of gets more difficult.
0:24:29 > 0:24:32So if you turn it now, you find it's quite easy, isn't it?
0:24:32 > 0:24:35It's not too bad. So let's see if you can do the bottom one.
0:24:35 > 0:24:38Let's do that one. And then the other ones.
0:24:38 > 0:24:41You've got that one.
0:24:42 > 0:24:45Just a bit faster. I think you can do it.
0:24:46 > 0:24:48That's it, you've got them.
0:24:48 > 0:24:50Right, great. Well done.
0:24:50 > 0:24:51APPLAUSE
0:24:51 > 0:24:54Thank you, Daniel. Go back up there, thank you.
0:25:00 > 0:25:05So, Daniel there converted his muscular energy into kinetic energy
0:25:05 > 0:25:08and into electrical energy. So, let's go to our...
0:25:08 > 0:25:13This energy meter again, the kind of scores on the doors.
0:25:13 > 0:25:15So, this is our target.
0:25:15 > 0:25:19How much has that hand-cranked generator given us?
0:25:20 > 0:25:25Unfortunately, a measly 12 AA batteries, OK?
0:25:25 > 0:25:29So, even if Daniel was at that for a long, long time,
0:25:29 > 0:25:33he wouldn't really generate enough to power this lecture theatre.
0:25:33 > 0:25:39But can we use this principle to get us closer to our target?
0:25:39 > 0:25:43And here I need two more volunteers.
0:25:43 > 0:25:47OK, the one at the end there, and if you wanted to come down.
0:25:47 > 0:25:49OK? If you want to come down.
0:25:49 > 0:25:50APPLAUSE
0:25:50 > 0:25:53- Can I take your name? - I'm Dan.- Dan?- Alex.- Alex.
0:25:53 > 0:25:57OK, so, we're going to send you on a bit of a journey.
0:25:57 > 0:26:01Not too far, it's just a journey within the Royal Institution.
0:26:01 > 0:26:06So if we could have a couple of our production team to take you away.
0:26:06 > 0:26:08OK, Dan and Alex, thank you.
0:26:10 > 0:26:14So, over the past few weeks,
0:26:14 > 0:26:20my team here has rigged the Royal Institution with lots of different
0:26:20 > 0:26:24types of energy generators
0:26:24 > 0:26:27and thrown in some newer technologies, as well.
0:26:27 > 0:26:30So, as you came into the building -
0:26:30 > 0:26:34I don't know if you noticed - you went over a very special floor.
0:26:34 > 0:26:38It generates electricity out of your footsteps
0:26:38 > 0:26:41and it works a lot like a Faraday's generator.
0:26:41 > 0:26:44So I think we've got some footage. So there - that's the one.
0:26:44 > 0:26:50You see, those steps were pushing magnets into copper coils,
0:26:50 > 0:26:53so it's a bit like the electrical generators I showed you as a display
0:26:53 > 0:26:57and that rod, and it generates a small electric current.
0:26:57 > 0:27:00So, how much energy or electricity did it generate?
0:27:00 > 0:27:02So, let's go back to our energy meter.
0:27:02 > 0:27:05So, it was just for over a week.
0:27:05 > 0:27:07If it comes down...
0:27:09 > 0:27:12Erm... Yes.
0:27:12 > 0:27:15Just one AA battery. We didn't cover a large area -
0:27:15 > 0:27:18obviously a large area would have done a lot better.
0:27:18 > 0:27:21So, up on the roof, you may not believe it,
0:27:21 > 0:27:25but we've actually got a fully functional wind machine
0:27:25 > 0:27:29and wind turbine attached. And that is a live shot right now,
0:27:29 > 0:27:32and you can see it's been raining. I don't know if some of you noticed.
0:27:32 > 0:27:35So that is a live shot of that wind turbine.
0:27:35 > 0:27:37So, is it Alex or Dan up there?
0:27:37 > 0:27:40All right, great, we can see Alex coming.
0:27:40 > 0:27:42- Careful.- OK, she's coming up the ladder.
0:27:42 > 0:27:46- And, Alex, can you hear me? - Yeah.- Oh, great.
0:27:46 > 0:27:48So, we've got that wind turbine up there.
0:27:48 > 0:27:52Can you go and see if you can find out what the reading is from the wind turbine, OK?
0:27:52 > 0:27:56- Four kilowatt-hours. - Four kilowatt-hours?
0:27:56 > 0:27:58OK, well, thank you, Alex.
0:27:58 > 0:28:01If you want to make your way down, OK? Thank you.
0:28:01 > 0:28:03APPLAUSE
0:28:08 > 0:28:10OK, she said four kilowatt-hours.
0:28:10 > 0:28:13We can actually try and convert that into our energy meter,
0:28:13 > 0:28:15which means we want to do that in AA batteries, OK?
0:28:15 > 0:28:19So let's see what that value is. So, this is our target.
0:28:19 > 0:28:22It's coming down. This is our wind turbine.
0:28:22 > 0:28:281,569 AA batteries.
0:28:28 > 0:28:32So not too bad, and it wasn't up there for too long.
0:28:32 > 0:28:38We've, finally, sent Dan to the men's toilet.
0:28:38 > 0:28:41Last week we installed a special cell
0:28:41 > 0:28:44that converts wee into electricity.
0:28:44 > 0:28:46So it's wee power.
0:28:46 > 0:28:48So you can see that time-lapse,
0:28:48 > 0:28:52you can see it being installed in one of the toilets upstairs here
0:28:52 > 0:28:55at the Royal Institution. So, we've got Dan here.
0:28:55 > 0:28:59So, Dan, again we've got a reading for how much energy
0:28:59 > 0:29:03that produced from that microbial fuel cell.
0:29:03 > 0:29:08- OK.- Tell us.- So, we've got 3.78 at the moment.
0:29:08 > 0:29:113.78. OK, thank you. Why don't you make your way back here?
0:29:11 > 0:29:14OK, thank you, Dan. APPLAUSE
0:29:22 > 0:29:25So, I want to say a bit more about that fuel cell.
0:29:25 > 0:29:27It's called up microbial fuel cell.
0:29:27 > 0:29:33What it does is it uses bacteria to convert wee into electricity.
0:29:33 > 0:29:36So, all the guys at the Royal Institution
0:29:36 > 0:29:38have been told to use that urinal.
0:29:38 > 0:29:43So, how much energy have we generated from using pee power?
0:29:43 > 0:29:46So let's go back to the meter.
0:29:46 > 0:29:50As usual, the target, and it goes down to...
0:29:52 > 0:29:54..two.
0:29:54 > 0:29:55A wee amount, yes.
0:29:55 > 0:29:57LAUGHTER
0:29:57 > 0:30:00So, that's just two AA batteries.
0:30:00 > 0:30:02So, many of these methods of generating electricity -
0:30:02 > 0:30:07particularly things like wind power - are what we call renewable,
0:30:07 > 0:30:10and that means that the energy is supplied from sources
0:30:10 > 0:30:12that are naturally replenished.
0:30:12 > 0:30:15At the moment, they just aren't
0:30:15 > 0:30:18giving us enough energy by themselves.
0:30:18 > 0:30:20That's true for the lecture theatre
0:30:20 > 0:30:23and it's true for the whole of the UK.
0:30:23 > 0:30:27So that means we still get about 50% of our energy
0:30:27 > 0:30:30or electricity from fossil fuels.
0:30:30 > 0:30:33So these are fossil fuels such as...
0:30:34 > 0:30:37Such as coal and oil.
0:30:38 > 0:30:41This is a bit of a dodgy oil - it tells pretty rude jokes.
0:30:41 > 0:30:43It's called crude oil.
0:30:45 > 0:30:49But also, another fossil fuel is methane.
0:30:50 > 0:30:53So, why do we use fossil fuels?
0:30:53 > 0:30:55Well, two main reasons.
0:30:55 > 0:30:58First, they contain a lot of energy.
0:31:02 > 0:31:04Ooh, that was great.
0:31:10 > 0:31:12So, let's see that in slow motion.
0:31:12 > 0:31:16So you can see, there's the balloon, there's the flame.
0:31:16 > 0:31:20And what's interesting is you see the plastic balloon going off first,
0:31:20 > 0:31:24before you see any ignition of the methane,
0:31:24 > 0:31:27but it'll happen in a minute. There it goes. There it goes.
0:31:32 > 0:31:34So that's what I call a real flame.
0:31:34 > 0:31:38There's another reason behind why we use fossil fuel -
0:31:38 > 0:31:43is that it's buried under our feet, so we can actually get to it.
0:31:43 > 0:31:47But how do we turn that fossil fuel into electricity?
0:31:47 > 0:31:50Well, there's something I've prepared earlier to help me explain.
0:31:51 > 0:31:57It might not look like it, but this is a fossil-fuel power station.
0:31:59 > 0:32:02OK? Well, what we've got here is
0:32:02 > 0:32:05we've got water in this pan and underneath
0:32:05 > 0:32:09we've got the burning fossil fuel - in this case, natural gas.
0:32:09 > 0:32:14And what it's going to do is, that steam from the water
0:32:14 > 0:32:18is going to turn this fan here,
0:32:18 > 0:32:22and that fan is very close to the electrical generator.
0:32:22 > 0:32:25So you can see the coils here.
0:32:25 > 0:32:27It's a bit like the generator we saw earlier.
0:32:27 > 0:32:31And hopefully it will... Just by steam...
0:32:33 > 0:32:35..it will light up these lights here.
0:32:35 > 0:32:38Yes, so you can see there, lights going on.
0:32:39 > 0:32:43And that's just from steam.
0:32:44 > 0:32:49So, in a sense, all power stations can be viewed as giant kettles.
0:32:49 > 0:32:55The only difference is how we boil the water - either coal or gas.
0:32:55 > 0:32:58And in nuclear power stations,
0:32:58 > 0:33:03the heat is from splitting up atoms - usually uranium.
0:33:03 > 0:33:09So, massive power stations like these generate electricity for
0:33:09 > 0:33:11the majority of the world's population.
0:33:11 > 0:33:14I would call them masterpieces of engineering,
0:33:14 > 0:33:16but we rarely see inside them.
0:33:16 > 0:33:17In a way, we take them for granted
0:33:17 > 0:33:19because they generate our electricity.
0:33:19 > 0:33:23So I asked another Christmas lecturer, Professor Tony Ryan,
0:33:23 > 0:33:27to go behind the scenes at Britain's biggest power station.
0:33:28 > 0:33:31Hello, Saiful. Hello, kids in the audience.
0:33:31 > 0:33:34I'm here at Britain's biggest power station.
0:33:34 > 0:33:37It's called Drax and it's enormous.
0:33:37 > 0:33:41I want to show you how it works and how it scales up from the model you
0:33:41 > 0:33:43have in front of you in the theatre.
0:33:49 > 0:33:52The noise in here is incredible.
0:33:52 > 0:33:56There are six generators, each with five turbines.
0:33:56 > 0:34:00They generate enough power for a million households.
0:34:00 > 0:34:05That's the most energy generated anywhere in the UK.
0:34:05 > 0:34:09And the turbines work just like you've seen in the lecture theatre -
0:34:09 > 0:34:13energy gets converted into heat, heat into motion,
0:34:13 > 0:34:15motion into electricity.
0:34:15 > 0:34:17You can't see the turbines themselves
0:34:17 > 0:34:20cos they have to keep running so the lights stay on,
0:34:20 > 0:34:24but we will go look in one that's been taken apart.
0:34:32 > 0:34:34Wow! This is enormous!
0:34:35 > 0:34:38So, this is Steve Austin, the chief turbine engineer.
0:34:38 > 0:34:42So, Steve, how fast does this go round?
0:34:42 > 0:34:46This will spin at 3,000 rpm, or 50 times a second.
0:34:46 > 0:34:50The blade tips, they will spin at 1,250 mph,
0:34:50 > 0:34:52which is 1.6 times the speed of sound.
0:34:52 > 0:34:56And how often do you have to look inside them to make sure everything's OK?
0:34:56 > 0:34:59Well, we run for eight years in between inspections,
0:34:59 > 0:35:02but this turbine in particular has run for 34 years,
0:35:02 > 0:35:05which is about 270,000 hours in service.
0:35:08 > 0:35:12For most of its life, Drax burned coal.
0:35:12 > 0:35:14But we're going to stop using coal
0:35:14 > 0:35:17for power in the UK over the next ten years.
0:35:17 > 0:35:22So Drax has switched to using these - compressed biomass pellets -
0:35:22 > 0:35:25and they're stored in these massive domes
0:35:25 > 0:35:27that are bigger than the Albert Hall.
0:35:27 > 0:35:29Up and down the country,
0:35:29 > 0:35:33huge power stations like this are keeping the lights on,
0:35:33 > 0:35:36the ovens cooking, the homes heated,
0:35:36 > 0:35:41all operating on the same principles identified by Michael Faraday
0:35:41 > 0:35:42over 200 years ago.
0:35:51 > 0:35:53OK, thank you, Tony, for that.
0:35:53 > 0:35:59As we know, burning fossil fuels is a major problem in terms of
0:35:59 > 0:36:04releasing carbon dioxide, which contributes to global warming.
0:36:04 > 0:36:06But right now, fossil fuels are
0:36:06 > 0:36:08still a very useful source of energy.
0:36:08 > 0:36:11So, where do fossil fuels get their energy from?
0:36:11 > 0:36:14Millions of years ago,
0:36:14 > 0:36:17coal, oil and gas
0:36:17 > 0:36:21used to be living things - plants and animals.
0:36:21 > 0:36:26And these plants and animals got their energy from the sun.
0:36:26 > 0:36:30So in the very long term, fossil fuels are essentially...
0:36:31 > 0:36:35..solar-powered. And this begs the question -
0:36:35 > 0:36:38where does the sun get its energy from?
0:36:38 > 0:36:40Right at the start of the lecture,
0:36:40 > 0:36:44we defined energy as the ability to do work.
0:36:44 > 0:36:46But there's another way to define energy,
0:36:46 > 0:36:50through the most famous equation of all time.
0:36:50 > 0:36:53Anyone know what that equation is?
0:36:53 > 0:36:56- AUDIENCE:- E=mc squared.
0:36:56 > 0:37:00E=mc squared. There we have it there.
0:37:01 > 0:37:06E is for energy, m is for mass
0:37:06 > 0:37:09and c is a huge number -
0:37:09 > 0:37:11the speed of light.
0:37:11 > 0:37:15This was formulated over a century ago by one of the most famous
0:37:15 > 0:37:18scientists of all time, Albert Einstein.
0:37:19 > 0:37:25This famous equation tells us a very important fact -
0:37:25 > 0:37:29mass, the stuff that makes up the whole world, makes us up,
0:37:29 > 0:37:31is equivalent to energy.
0:37:32 > 0:37:35They are interchangeable - just different forms.
0:37:35 > 0:37:39This tells us a tiny amount of mass contains
0:37:39 > 0:37:41a colossal amount of energy.
0:37:44 > 0:37:49So I was racking my brain, trying to find a good way of visualising this,
0:37:49 > 0:37:52and we've done some very complicated calculations.
0:37:52 > 0:37:55We've come up with the most sophisticated example.
0:37:57 > 0:37:58My pants.
0:38:00 > 0:38:06You'd be amazed at how much energy there is in these pants.
0:38:06 > 0:38:10According to that famous equation we just said - E=mc squared -
0:38:10 > 0:38:14they contain enough energy to power the city of Birmingham.
0:38:16 > 0:38:19Lucky Birmingham! So, er, let's put it there.
0:38:19 > 0:38:22So let's put it to the test.
0:38:22 > 0:38:27We're going to burn those pants and there is a scientific term for it -
0:38:27 > 0:38:30it's called burn, pants, burn.
0:38:32 > 0:38:35And let's see, OK?
0:38:35 > 0:38:37Right. We're going to...
0:38:37 > 0:38:41Just to speed up the reaction, we're going to use some liquid oxygen...
0:38:43 > 0:38:47..and just to see the effects. So let me get this going.
0:39:03 > 0:39:06Yeah, I never liked those pants, actually, so...
0:39:08 > 0:39:12So, is that enough energy, do you think, to power Birmingham?
0:39:14 > 0:39:15I don't think so.
0:39:15 > 0:39:19So, in scientific terms, we call that liar, liar, pants on fire.
0:39:21 > 0:39:25And that's because the energy in those pants is hard to get at.
0:39:26 > 0:39:29My pants are hard to get at, as well!
0:39:29 > 0:39:31Simply setting them on fire...
0:39:33 > 0:39:38..only releases the energy of the bonds holding the atoms together.
0:39:38 > 0:39:41So if you really want to power Birmingham,
0:39:41 > 0:39:46the atoms need to undergo a series of nuclear reactions,
0:39:46 > 0:39:49either to split them or fuse them together.
0:39:50 > 0:39:56It's only then that the mass releases that vast amount of energy
0:39:56 > 0:39:59we saw from our equation, E=mc squared.
0:39:59 > 0:40:04So, this helps us understand why the sun is so powerful.
0:40:05 > 0:40:07It's converting
0:40:07 > 0:40:12enormous amounts of mass all the time - mostly hydrogen -
0:40:12 > 0:40:16into vast amounts of raw energy in the form of heat and light.
0:40:17 > 0:40:22It's actually the biggest energy converter in the whole solar system.
0:40:23 > 0:40:27So, can we do the same thing here on Earth?
0:40:27 > 0:40:30And the simple answer is, yes, we can.
0:40:30 > 0:40:32What we're seeing here...
0:40:34 > 0:40:36..works on the same principle.
0:40:36 > 0:40:41It's basically converting the mass of hydrogen directly into energy.
0:40:41 > 0:40:44It's a hydrogen bomb,
0:40:44 > 0:40:47the most destructive weapon in the world.
0:40:48 > 0:40:52But there is hope that we can carry out a more controlled version of
0:40:52 > 0:40:56this reaction we've just seen, and it's called nuclear fusion.
0:40:57 > 0:40:58So, what is nuclear fusion?
0:41:00 > 0:41:02To help me answer that question, I'd like you to welcome,
0:41:02 > 0:41:05from the UK Atomic Energy Authority, Professor Ian Chapman.
0:41:10 > 0:41:12- Hello, Ian. - Hi, Saiful, how are you?
0:41:14 > 0:41:17Thank you for joining us, Ian.
0:41:17 > 0:41:19This is a very interesting contraption.
0:41:19 > 0:41:20I know it's related to nuclear fusion.
0:41:20 > 0:41:22Tell us a bit more.
0:41:22 > 0:41:25So, to get nuclear fusion to happen here on earth
0:41:25 > 0:41:27we have to get the fuel incredibly hot,
0:41:27 > 0:41:31sort of "ten times hotter than the centre of the sun" hot.
0:41:31 > 0:41:33So this... Obviously, we're not doing that here,
0:41:33 > 0:41:37but this is a demonstration of what happens when we do do that.
0:41:37 > 0:41:41So when we put the fuel under these incredibly intense temperatures,
0:41:41 > 0:41:45you make the fuel very energetic and when you do that,
0:41:45 > 0:41:48the ions and electrons which are inside the gas separate.
0:41:48 > 0:41:50So you separate those charged particles
0:41:50 > 0:41:52and that gives you a plasma,
0:41:52 > 0:41:55and that's what you can see inside this cage in here.
0:41:55 > 0:41:58So this sort of beautiful cloud, this ball of light, is a plasma.
0:41:58 > 0:42:01OK, you've mentioned the word "plasma". So, what is plasma?
0:42:01 > 0:42:03So, plasma is the fourth state of matter.
0:42:03 > 0:42:07So you have solid, then a liquid, then a gas, and then a plasma.
0:42:07 > 0:42:10And a plasma is essentially a very energetic gas, where you've
0:42:10 > 0:42:12heated up the gas to extreme energies
0:42:12 > 0:42:14and the ions and the electrons have separated,
0:42:14 > 0:42:17so you have a charged ball of ionised gas.
0:42:17 > 0:42:21You've brought us another interesting contraption here.
0:42:21 > 0:42:25I understand that plasma isn't easy to control,
0:42:25 > 0:42:26so how do you control plasma?
0:42:26 > 0:42:29That's exactly the difficulty with having fusion reactors,
0:42:29 > 0:42:31is controlling the plasma. So again,
0:42:31 > 0:42:35we're going to spark a current through this tube and once again
0:42:35 > 0:42:36we have this plasma.
0:42:36 > 0:42:40But because the plasma is charged, so you have ions and electrons here,
0:42:40 > 0:42:42it will feel a magnetic field. So I have a simple magnet.
0:42:42 > 0:42:44If I put the magnet near it,
0:42:44 > 0:42:47you can see how the plasma is reacting to the magnet -
0:42:47 > 0:42:50it moves because the magnetic field is near it.
0:42:50 > 0:42:53So let me have a go at that. It looks really good. So, basically,
0:42:53 > 0:42:58you're just using the fact that it's charged to control it with this kind
0:42:58 > 0:43:00of magnetic field, or a strong magnet.
0:43:00 > 0:43:03Exactly, and that's how you would go about building a fusion reactor,
0:43:03 > 0:43:06because, as I said, you have a fuel which is incredibly hot,
0:43:06 > 0:43:09so you need to keep it away from the wall of the reactor.
0:43:09 > 0:43:11And we do that by creating a sort of magnetic cage,
0:43:11 > 0:43:14a magnetic bottle to hold the fuel in.
0:43:14 > 0:43:19OK. Will we see a nuclear fusion reactor very soon?
0:43:19 > 0:43:20That's what we're hoping for.
0:43:20 > 0:43:23So we're building a machine in the south of France right now.
0:43:23 > 0:43:25That will be a proof of principle.
0:43:25 > 0:43:28It will get ten times the amount of energy out that we put in to get
0:43:28 > 0:43:30the reaction going in the first place,
0:43:30 > 0:43:32on a sort of 500-megawatt scale,
0:43:32 > 0:43:34and soon thereafter we hope to be building reactors.
0:43:34 > 0:43:37- Great. Well, thank you, Ian Chapman. - Thank you.
0:43:37 > 0:43:39APPLAUSE
0:43:43 > 0:43:47So, fusion works on a large scale.
0:43:47 > 0:43:52It could mean unlimited quantities of electricity with hardly any
0:43:52 > 0:43:54carbon emissions. Obviously,
0:43:54 > 0:43:58this is a scientific challenge and it will take years to crack.
0:43:58 > 0:44:03So let me return to that giant nuclear furnace in the sky, the sun,
0:44:03 > 0:44:05the light that never goes out.
0:44:07 > 0:44:10So, did you know that in just two hours,
0:44:10 > 0:44:16enough energy from the sun hits the Earth to power human activity
0:44:16 > 0:44:18for a whole year?
0:44:18 > 0:44:21We can already convert the sun's energy
0:44:21 > 0:44:23directly into electricity using...
0:44:24 > 0:44:26..solar panels.
0:44:26 > 0:44:28And this is something I'm really excited about -
0:44:28 > 0:44:30it's one of my research areas.
0:44:30 > 0:44:34So for this next bit, I need a volunteer,
0:44:34 > 0:44:37and somebody who is not scared of heights.
0:44:37 > 0:44:39OK, I should come over to this side. I haven't been over there.
0:44:39 > 0:44:42So, yeah, do you want to come through? Come on.
0:44:47 > 0:44:48Hello. Hello, there.
0:44:48 > 0:44:50- Can I take your name?- Natasha.
0:44:50 > 0:44:52Natasha. This is Natasha.
0:44:52 > 0:44:54So, Natasha, I asked about scared of heights
0:44:54 > 0:44:57because you're going on a journey, as well.
0:44:57 > 0:45:00So, one of the production team is going to take you off
0:45:00 > 0:45:02to look at some interesting technology, OK?
0:45:02 > 0:45:04So, back to our big challenge.
0:45:04 > 0:45:09Can we power this lecture theatre?
0:45:09 > 0:45:13I've covered the roof of the Royal Institution with solar panels.
0:45:13 > 0:45:17So this is actually a live shot. And it is live, you can tell -
0:45:17 > 0:45:22it's raining, covered in water - and they've been plugged into a battery.
0:45:22 > 0:45:26So there's the battery, and that's the live shot, looking very wet.
0:45:26 > 0:45:28And that line there...
0:45:29 > 0:45:33..has gone down and it's come into this lecture theatre.
0:45:33 > 0:45:35And that is the line.
0:45:35 > 0:45:37So we're going to try and test it out.
0:45:37 > 0:45:41Let's see if our volunteer, Natasha, has got up to the roof.
0:45:41 > 0:45:42OK, here comes Natasha.
0:45:42 > 0:45:45She's on the roof and we're going to
0:45:45 > 0:45:48try and get a reading of our battery.
0:45:48 > 0:45:49Natasha, can you hear me?
0:45:49 > 0:45:51- Yes, I can.- OK.
0:45:51 > 0:45:55- So, can you give us a reading from that battery?- Certainly.
0:45:56 > 0:45:58The power is...
0:45:58 > 0:46:02110, and that's 4.7 kilowatt-hours.
0:46:02 > 0:46:06And do you want to read us the number below that, as well?
0:46:06 > 0:46:07That's 97%.
0:46:07 > 0:46:09OK. Well, thank you, Natasha.
0:46:09 > 0:46:11I think you deserve to come back out of the wind and rain.
0:46:11 > 0:46:13OK, thank you.
0:46:18 > 0:46:20Let's give us our reading on our energy meters.
0:46:20 > 0:46:22We've got a couple of readings.
0:46:22 > 0:46:24So, that was our target...
0:46:25 > 0:46:26..and we're down to...
0:46:28 > 0:46:33..2,314 AA batteries
0:46:33 > 0:46:35from those solar panels.
0:46:36 > 0:46:39OK, and by the way, I've used a small bit of electricity to make
0:46:39 > 0:46:42a solar-powered snack.
0:46:42 > 0:46:43So watch this.
0:46:45 > 0:46:47Very burnt toast.
0:46:47 > 0:46:49See? But that was directly from
0:46:49 > 0:46:53the solar panels hooked onto that battery and down here.
0:46:54 > 0:46:58So, those panels up there are made of silicon,
0:46:58 > 0:47:01but take a look at these.
0:47:01 > 0:47:06These are next-generation solar panels, solar materials.
0:47:06 > 0:47:10As you can see, much more flexible. A bit lighter, as well.
0:47:10 > 0:47:15And they're made of much more exotic materials -
0:47:15 > 0:47:19copper, indium, gallium and selenium.
0:47:20 > 0:47:22And we're going to hook them up...
0:47:22 > 0:47:24I'm just going to put this down here.
0:47:28 > 0:47:30OK? We're going to hook them up
0:47:30 > 0:47:35to this electric spark generator.
0:47:35 > 0:47:38And what the solar panel here will do
0:47:38 > 0:47:42is try and generate electricity directly.
0:47:42 > 0:47:45And what we need is some - obviously - light,
0:47:45 > 0:47:48light directly onto those panels.
0:47:48 > 0:47:52And in this case, we've got a couple of lamps there.
0:47:52 > 0:47:54So we need the lights on, OK?
0:47:54 > 0:47:55And I'm going to turn this.
0:47:58 > 0:48:00So we can probably dim the lights a bit.
0:48:05 > 0:48:07Yeah?
0:48:07 > 0:48:10So we've done it - we've got some sparks flying
0:48:10 > 0:48:13just from this panel here and a couple of lights.
0:48:13 > 0:48:16And the lights off, and it stops.
0:48:16 > 0:48:20So, basically, it wouldn't work without that light energy.
0:48:22 > 0:48:25So, new, exotic materials and new-generation panels like this
0:48:25 > 0:48:29are really changing how we can use solar design.
0:48:29 > 0:48:33So, how much of the sun's energy can solar panels harness?
0:48:33 > 0:48:36To understand that, we need to understand light.
0:48:36 > 0:48:39Sunlight isn't made up of just one colour -
0:48:39 > 0:48:43it's made up of lots of different colours, all mixed together.
0:48:43 > 0:48:47To show you this, I've got a very bright light to simulate the sun.
0:48:47 > 0:48:50It's got a special filter that splits light
0:48:50 > 0:48:52into its component parts.
0:48:52 > 0:48:56So each one of these colours carries a certain amount of energy.
0:48:56 > 0:48:59So this is split up, so you can see this here.
0:48:59 > 0:49:04That's like a typical rainbow that you see and we are unweaving
0:49:04 > 0:49:07the rainbow there. But, for this,
0:49:07 > 0:49:11the data on that computer actually is going to read out the different
0:49:11 > 0:49:15energy levels. But, for that, we do need a volunteer.
0:49:15 > 0:49:16So, can I take your name?
0:49:16 > 0:49:17- Tess.- Tess.
0:49:17 > 0:49:19So, Tess, when I ask you to,
0:49:19 > 0:49:23can you shout out the numbers that you see on that computer screen?
0:49:23 > 0:49:24Is that OK? Great.
0:49:24 > 0:49:27So, what we have here is a solar panel a bit like the ones on
0:49:27 > 0:49:30the roof that you saw earlier. And what it does - it's very clever -
0:49:30 > 0:49:35it tells us the different energy levels across that spectrum.
0:49:35 > 0:49:39And what it's trying to show us is that there are different energies
0:49:39 > 0:49:41within the different colours.
0:49:41 > 0:49:43So let's see what we get from the readout.
0:49:43 > 0:49:46I'm going to start at the blue end, since I'm on this side here.
0:49:46 > 0:49:49So, Tess, if you could start telling us some values.
0:49:49 > 0:49:53So it starts off probably at zero, so what have you got at the moment?
0:49:53 > 0:49:55- Eight.- Eight, OK.
0:49:55 > 0:49:57So let me move along a bit further.
0:49:58 > 0:50:0010. 14.
0:50:00 > 0:50:0414? So already, when we're getting towards the kind of greeny colour,
0:50:04 > 0:50:07we're getting to 14. OK. How about around yellow?
0:50:07 > 0:50:09- What have we got for yellow?- 12.
0:50:09 > 0:50:1212. OK, we're going towards orange.
0:50:12 > 0:50:17- Ten.- Ten, and now the red end, right down here...
0:50:17 > 0:50:19- Six.- Six.
0:50:19 > 0:50:22So you can see straightaway that all the numbers,
0:50:22 > 0:50:24in a very general way, are not the same.
0:50:27 > 0:50:32So, solar panels can't capture all wavelengths of light -
0:50:32 > 0:50:36they stop working at certain regions in the spectrum,
0:50:36 > 0:50:39depending on the material they're made of.
0:50:40 > 0:50:44Tackling this issue is one of the big challenges
0:50:44 > 0:50:46of solar-cell design.
0:50:46 > 0:50:48It's one of my research areas, as well.
0:50:49 > 0:50:52But compared to most other things,
0:50:52 > 0:50:55solar cells are still very efficient.
0:50:55 > 0:50:59They can already do some pretty amazing things.
0:50:59 > 0:51:02I want to show you one of my favourites -
0:51:02 > 0:51:08a plane powered using nothing but energy from the sun.
0:51:08 > 0:51:12So we're going to speak to the two pilots of this plane,
0:51:12 > 0:51:16Bertrand Piccard and Andre Borschberg, right now,
0:51:16 > 0:51:17on the line from Switzerland.
0:51:19 > 0:51:20Yes, hello from Switzerland.
0:51:22 > 0:51:23Landing now at BBC.
0:51:25 > 0:51:29Thank you for joining us, Andre. Thank you for joining us, Bertrand.
0:51:29 > 0:51:30With pleasure.
0:51:30 > 0:51:32Tell us how far you've got with your solar-powered plane.
0:51:32 > 0:51:35With Solar Impulse, we went the furthest we could go.
0:51:35 > 0:51:38That means all around the world.
0:51:38 > 0:51:40Tell us a bit about the plane itself.
0:51:40 > 0:51:45So, imagine the task for the engineers that were led by Andre,
0:51:45 > 0:51:49to make a plane that was the size of
0:51:49 > 0:51:53a jumbo jet, 236 feet wingspan,
0:51:53 > 0:51:55and the weight of a family car - two tonnes.
0:51:55 > 0:51:57It's really, absolutely amazing.
0:51:57 > 0:51:59Nobody thought we could do it.
0:51:59 > 0:52:02But if you are a pioneer, an explorer,
0:52:02 > 0:52:05you don't listen to people who say it's impossible.
0:52:05 > 0:52:09You use their scepticism as a motivation,
0:52:09 > 0:52:12as a stimulation, to prove that you can do it.
0:52:12 > 0:52:14What was the toughest part of the journey?
0:52:14 > 0:52:16But of course, for us, the difficulty
0:52:16 > 0:52:19and the challenge was to fly over the ocean.
0:52:19 > 0:52:21We flew over land with the first airplane,
0:52:21 > 0:52:24so I think we knew how to fly such an airplane,
0:52:24 > 0:52:27but to go over the ocean for many days, many nights,
0:52:27 > 0:52:30we didn't know if the airplane would be able to make it,
0:52:30 > 0:52:32we didn't know if we could forecast the weather well enough,
0:52:32 > 0:52:33and of course, we didn't know if
0:52:33 > 0:52:36a pilot in fact could sustain such a long flight.
0:52:36 > 0:52:39Because you have to understand that it's an aeroplane that can
0:52:39 > 0:52:42fly forever, at least theoretically.
0:52:42 > 0:52:44The sun is charging the batteries
0:52:44 > 0:52:46and running the motors during the day flight,
0:52:46 > 0:52:49in order to fly through the night with the batteries
0:52:49 > 0:52:51and reach the next sunrise.
0:52:51 > 0:52:55So my flight from America to Europe across the Atlantic
0:52:55 > 0:52:58was three days and three nights and, for all this time,
0:52:58 > 0:53:01you have to be like in the science-fiction film -
0:53:01 > 0:53:05you look at the sun, you look at your electric motors turning,
0:53:05 > 0:53:08you think, "Wow! That's the future. That's a fairy tale."
0:53:08 > 0:53:12No fuel, no pollution, no noise, flying forever.
0:53:12 > 0:53:13And it's not the future.
0:53:13 > 0:53:16What is magic with clean technologies
0:53:16 > 0:53:17is that it is the present.
0:53:17 > 0:53:21It's what is allowed now by renewable energies.
0:53:21 > 0:53:25So we currently see planes carrying 200 to 300 people.
0:53:25 > 0:53:26Do you ever see a time when
0:53:26 > 0:53:28solar-powered planes could do the same?
0:53:28 > 0:53:33I would be crazy to answer "yes" and stupid to answer "no",
0:53:33 > 0:53:36because today we don't have the technology for that,
0:53:36 > 0:53:39but Charles Lindbergh neither had the technology to do it
0:53:39 > 0:53:44when he crossed the Atlantic in 1927 and, nevertheless, it happened.
0:53:44 > 0:53:47Thank you, Andre. Thank you, Bertrand.
0:53:47 > 0:53:48Bye-bye for now.
0:53:48 > 0:53:52- With pleasure. Bye-bye. - Bye-bye. Take care.
0:54:03 > 0:54:07Solar power is unlikely to give us all the energy in the UK because
0:54:07 > 0:54:09we have a limited land space.
0:54:09 > 0:54:12And it's a challenge during the winter months -
0:54:12 > 0:54:16at least here in northern Europe - but with more research,
0:54:16 > 0:54:19they will play a bigger role in the future.
0:54:19 > 0:54:23So, finally, let's return to our big question -
0:54:23 > 0:54:28can we power the lecture theatre using the mix of energy sources
0:54:28 > 0:54:30that we've generated here?
0:54:32 > 0:54:35OK, so, there's only one way to find out, as ever,
0:54:35 > 0:54:38and that is to look at our scores on our energy meter.
0:54:38 > 0:54:42So, let's have a final drumroll, please.
0:54:42 > 0:54:44Come on, give us a big drumroll.
0:54:47 > 0:54:48Let's see how far we got.
0:54:48 > 0:54:51So, first, our candles.
0:54:53 > 0:54:56And it was a little blip.
0:54:56 > 0:54:58What about our special floor?
0:55:00 > 0:55:03Tiny. Our wind turbine?
0:55:05 > 0:55:07A bit better. Our wee power?
0:55:09 > 0:55:12Yeah, a drip, really, isn't it?
0:55:12 > 0:55:14And lastly, our solar panels.
0:55:15 > 0:55:17There.
0:55:17 > 0:55:23And that gives us a total of 3,937 AA batteries.
0:55:26 > 0:55:30Well, even with all that clever equipment, we've not made it.
0:55:30 > 0:55:34That's because this lecture theatre, and society as a whole,
0:55:34 > 0:55:36is incredibly energy hungry.
0:55:37 > 0:55:39To reach the target in a week,
0:55:39 > 0:55:43we'd have to use nine times as many solar panels,
0:55:43 > 0:55:46or 14 wind turbines on the roof.
0:55:47 > 0:55:52Unless, of course, we unlocked the energy in these -
0:55:52 > 0:55:55my pants - through nuclear fusion.
0:55:55 > 0:55:59That would light up the whole of Piccadilly.
0:55:59 > 0:56:03I'm optimistic the energy gap will be filled.
0:56:03 > 0:56:08And as this is our 80th anniversary, I want to celebrate.
0:56:08 > 0:56:10So, please welcome one of the stars
0:56:10 > 0:56:14of this year's Great British Bake Off, Selasi.
0:56:14 > 0:56:17CHEERING AND APPLAUSE
0:56:23 > 0:56:25Great. Great to see you.
0:56:25 > 0:56:27Great to see you, buddy.
0:56:28 > 0:56:30- Welcome, Selasi. Thanks for joining us.- Thank you.
0:56:30 > 0:56:33You were one of our family favourites.
0:56:33 > 0:56:37What's it like, being on The Great British Bake Off?
0:56:37 > 0:56:39It's really fun, so if you ever
0:56:39 > 0:56:42change your mind about science you can...
0:56:42 > 0:56:45You can go in. But it was really, really fun. Very challenging.
0:56:45 > 0:56:49- So, could you begin to ice that last cake there...- Sure.
0:56:49 > 0:56:51..while I explain what we've got here?
0:56:51 > 0:56:55So, these cakes represent the different years
0:56:55 > 0:56:58and the different amounts, or proportions, of energy
0:56:58 > 0:57:02used in the UK to generate our energy.
0:57:02 > 0:57:05So, 80 years ago - it's our 80th anniversary...
0:57:05 > 0:57:081936, and you can see the big,
0:57:08 > 0:57:11gigantic black slice,
0:57:11 > 0:57:14indicating that coal dominated 80 years ago.
0:57:14 > 0:57:16And we've come on a long way.
0:57:16 > 0:57:22If you now go to this year, renewables in green, coal in black.
0:57:22 > 0:57:25For the first time, this year,
0:57:25 > 0:57:29the UK generated more energy from renewables than from coal.
0:57:30 > 0:57:35So, our goal in the future is to double our renewables.
0:57:35 > 0:57:39So this last cake that Selasi has beautifully iced
0:57:39 > 0:57:43represents our ambition.
0:57:43 > 0:57:47So, not since Faraday's day has there been a more exciting time
0:57:47 > 0:57:51to be inventing new ways of generating energy.
0:57:51 > 0:57:57So get thinking - your ideas make a difference in the future.
0:57:57 > 0:57:59In the next lecture,
0:57:59 > 0:58:04we're going to look at how humans and other animals use energy.
0:58:04 > 0:58:09So join us to find out if we can supercharge the human body.
0:58:09 > 0:58:11Thank you and goodnight.
0:58:11 > 0:58:13APPLAUSE