0:00:01 > 0:00:04HEART BEATING
0:00:20 > 0:00:23We are all more powerful than you might think.
0:00:23 > 0:00:25The sound you can hear now
0:00:25 > 0:00:28is actually the sound of my own heartbeat.
0:00:28 > 0:00:34And if you listen carefully, you can hear all of yours joining in.
0:00:41 > 0:00:42So you might think that this
0:00:42 > 0:00:46is just biology, but on a fundamental level,
0:00:46 > 0:00:49what's happening here is a transfer of energy.
0:00:49 > 0:00:53Every single one of us is a finely-tuned energy conversion machine,
0:00:53 > 0:00:56honed by millions of years of evolution.
0:00:58 > 0:01:02So, in this second Christmas lecture on our 80th birthday,
0:01:02 > 0:01:05I am going to investigate how humans,
0:01:05 > 0:01:10other animals and machines use energy.
0:01:11 > 0:01:14And whether we can supercharge ourselves
0:01:14 > 0:01:17to increase the performance of the human body.
0:01:17 > 0:01:22So, welcome to the 80th anniversary Royal Institution Christmas lectures!
0:01:22 > 0:01:25APPLAUSE
0:01:42 > 0:01:46We are all walking, talking powerhouses.
0:01:46 > 0:01:50I'm Saiful Islam. I'm a professor of chemistry at the University of Bath.
0:01:51 > 0:01:57Like you, my body is converting energy all the time.
0:01:57 > 0:02:02So let me show you, with this very sophisticated infrared camera.
0:02:02 > 0:02:05So this camera, unlike a normal one,
0:02:05 > 0:02:10it actually looks at heat rather than light.
0:02:10 > 0:02:12So, give us a wave, this bit of the audience.
0:02:12 > 0:02:15Come on. So, as you can imagine,
0:02:15 > 0:02:20bright red means hot and the blues are cold.
0:02:20 > 0:02:22So this side, give me a wave!
0:02:22 > 0:02:24OK, let me see if I can get you into focus.
0:02:24 > 0:02:27OK, so, quite a few.
0:02:27 > 0:02:29And, then, over here, let me get you into focus.
0:02:29 > 0:02:30Another wave.
0:02:32 > 0:02:35OK, so you're all, as you can tell, giving off heat.
0:02:35 > 0:02:37And, actually, wait a minute...
0:02:37 > 0:02:41There's either somebody seriously ill or...
0:02:41 > 0:02:43Or a bit dead.
0:02:43 > 0:02:46Oh, yeah, just a mannequin.
0:02:46 > 0:02:51OK, as I say, we are all giving off heat, so earlier,
0:02:51 > 0:02:55we took a temperature of this lecture theatre
0:02:55 > 0:03:00and it was 18.7 Celsius
0:03:00 > 0:03:02and this is the reading right now.
0:03:02 > 0:03:03So can you see that?
0:03:03 > 0:03:06It's 20.2.
0:03:06 > 0:03:09So, within an hour, it has gone up a bit.
0:03:09 > 0:03:12So we are generating quite a bit of energy.
0:03:12 > 0:03:15But just how much energy are we all using?
0:03:16 > 0:03:22Is the human body a gas guzzler or an energy saver?
0:03:24 > 0:03:28I think it was great to hear our heartbeats just now.
0:03:28 > 0:03:33Every one of you is wearing a chest monitor and I've got one, too.
0:03:33 > 0:03:34It's kind of strapped here.
0:03:34 > 0:03:36It feels a bit uncomfortable.
0:03:36 > 0:03:38And so what we're going to do,
0:03:38 > 0:03:39we're going to try and find out
0:03:39 > 0:03:42how much energy we all burn during this lecture.
0:03:42 > 0:03:45So these are a couple of laptops and you can see it's got
0:03:45 > 0:03:47lots of little squares.
0:03:47 > 0:03:51It's, basically, all the different energy monitors, so if you look,
0:03:51 > 0:03:53you can see, just about,
0:03:53 > 0:03:57the different numbers and the different data.
0:03:57 > 0:03:59And if you look at the screen, I don't know if you can see,
0:03:59 > 0:04:02but right in the top right-hand corner where there is a little flame,
0:04:02 > 0:04:04that's the calories burnt.
0:04:04 > 0:04:08The bottom left, where there is a little heart, that's your heart rate
0:04:08 > 0:04:13and the central figure is basically the energy consumption.
0:04:13 > 0:04:15But there is a twist to this live experiment.
0:04:17 > 0:04:20We want to split you up into two groups
0:04:20 > 0:04:23to do a bit of a large-scale experiment.
0:04:23 > 0:04:29So roughly from here, the central group here, to the right, OK?
0:04:29 > 0:04:32So it's going to be roughly here to the right.
0:04:32 > 0:04:33You're going to be in the group
0:04:33 > 0:04:36what I'm going to call The Movers And Shakers.
0:04:36 > 0:04:39And you're going to be moving up around all the time when you
0:04:39 > 0:04:41hear this music.
0:04:41 > 0:04:42MUSIC PLAYS
0:04:42 > 0:04:46Come on, let's get up. Get up. Come on. Up you get!
0:04:46 > 0:04:47Come on!
0:04:49 > 0:04:50That's it, come on.
0:04:52 > 0:04:55Come on. Come on, you can do better than that!
0:05:03 > 0:05:06MUSIC STOPS Right.
0:05:06 > 0:05:08Now, remember,
0:05:08 > 0:05:11remember when you next hear that music,
0:05:11 > 0:05:13I want you all to get up and do exactly the same thing,
0:05:13 > 0:05:15strut your funky stuff, OK?
0:05:15 > 0:05:19Right, the other group, you're going to do absolutely nothing.
0:05:21 > 0:05:24Actually, we've got a special scientific term for you guys.
0:05:24 > 0:05:28This group is going to be called The Couch Potato Group, OK?
0:05:28 > 0:05:30So we're going to see the difference,
0:05:30 > 0:05:32because we've got the chest monitors on.
0:05:32 > 0:05:34We're going to see the difference between the groups
0:05:34 > 0:05:36towards the end of the lecture.
0:05:36 > 0:05:38So as part of our 80th celebrations,
0:05:38 > 0:05:43we've invited Christmas lecturers past to help out.
0:05:43 > 0:05:45So to help us with this demonstration,
0:05:45 > 0:05:49it is a pleasure to introduce the 2007 lecturer,
0:05:49 > 0:05:50Professor Hugh Montgomery.
0:05:52 > 0:05:54He's up there.
0:06:04 > 0:06:06Hello, Hugh. Thank you for joining us.
0:06:06 > 0:06:08- It's pleasure. Thank you for having me.- How does it feel to be back?
0:06:08 > 0:06:11- Frankly terrifying, but less than it was last time, I think.- OK.
0:06:11 > 0:06:15Well, we've got Hugh to do something a bit special.
0:06:15 > 0:06:18We're going to ask Hugh to do as little as possible.
0:06:18 > 0:06:20He's going to, actually, just basically
0:06:20 > 0:06:22lie down up there for the rest of the lecture.
0:06:22 > 0:06:24- Right.- And we've got a special term for him.
0:06:24 > 0:06:26He is going to be called...
0:06:26 > 0:06:28The Lazy Lecturer. So, is that OK with you, Hugh?
0:06:28 > 0:06:31Absolutely fantastic. More sleep than I've had all week.
0:06:31 > 0:06:33Well, hopefully, they've made things comfortable for you.
0:06:33 > 0:06:36It looks lovely. I've got my coat, so it's a terrific pillow.
0:06:36 > 0:06:39OK, great. So where does all this energy we are burning come from?
0:06:39 > 0:06:44So, as a scientist, I love doing research
0:06:44 > 0:06:47and testing ideas.
0:06:47 > 0:06:52And I did an experiment on myself.
0:06:52 > 0:06:58So the experiment was that I would actually take a food diary
0:06:58 > 0:07:03and look at all the food I'd eaten over a whole week.
0:07:03 > 0:07:06As you can see, it's a pretty mixed and dodgy diet.
0:07:07 > 0:07:10So, this is the food I've taken in for a whole week,
0:07:10 > 0:07:13so I actually need a volunteer to help me...
0:07:13 > 0:07:16Well, actually, a couple of volunteers to help me scrape it in.
0:07:16 > 0:07:18So do you want to come down, yes?
0:07:18 > 0:07:21And one more? Sir, in the purple T-shirt.
0:07:21 > 0:07:22Yes, if you want to come down.
0:07:25 > 0:07:28- So if I take your name?- Iggy.
0:07:28 > 0:07:29Iggy?
0:07:29 > 0:07:31APPLAUSE
0:07:31 > 0:07:33INAUDIBLE
0:07:33 > 0:07:35- Tally?- Yeah.- So we got Iggy and Tally.
0:07:35 > 0:07:39So, you can see this is...some of the dodgy food I've eaten.
0:07:39 > 0:07:40Some of it better than others.
0:07:40 > 0:07:42So, we got a special task for you.
0:07:42 > 0:07:47We're going to, actually, ask you to pass on the food to Iggy and he's going to put
0:07:47 > 0:07:49it into that container there.
0:07:49 > 0:07:52So what we've got are some scales, a container
0:07:52 > 0:07:55and just do it as fast as you can.
0:07:55 > 0:07:56And if you just pass it on to Iggy
0:07:56 > 0:07:59and we just get that food into that container.
0:07:59 > 0:08:01- Do I just scoop it in?- Yeah, just scoop it in.
0:08:01 > 0:08:03So we're going to just measure it later.
0:08:03 > 0:08:04Just get it into that container, yeah.
0:08:04 > 0:08:09So you can see... Actually, I'm quite keen on muesli.
0:08:09 > 0:08:11There's quite a bit. I don't know how I ate so much soup!
0:08:11 > 0:08:15So we've got there. Then, OK...
0:08:15 > 0:08:16And, then...
0:08:16 > 0:08:18I think I had too much bread. MUSIC PLAYS
0:08:18 > 0:08:20OK, come on!
0:08:20 > 0:08:22Just carry on doing it, you do that.
0:08:22 > 0:08:23Come on!
0:08:33 > 0:08:34OK.
0:08:36 > 0:08:37OK.
0:08:37 > 0:08:39MUSIC STOPS
0:08:39 > 0:08:42Right. You just carry on doing that.
0:08:42 > 0:08:46And if you can't reach over, there's some stuff...
0:08:46 > 0:08:48There's some stuff underneath there.
0:08:48 > 0:08:49So while they are doing that,
0:08:49 > 0:08:52so I'd like you to welcome, to analyse the results,
0:08:52 > 0:08:55last year's Christmas lecturer, Doctor Kevin Fong.
0:08:59 > 0:09:02- Yes!- Hello, how are you?
0:09:06 > 0:09:08- Welcome back.- Thank you.
0:09:08 > 0:09:10How's it feel to be back in this theatre?
0:09:10 > 0:09:14Do you know, I really, really wish I was giving the lectures this year.
0:09:14 > 0:09:15You're welcome to take over.
0:09:15 > 0:09:17Yeah, I was kidding.
0:09:17 > 0:09:21You can do it. This is your weekly intake?
0:09:21 > 0:09:22It is, it is.
0:09:22 > 0:09:25So, we're getting them to pile it in there
0:09:25 > 0:09:27and I think they are nearly done.
0:09:27 > 0:09:29So I'll...
0:09:29 > 0:09:31Well done! So, I'm going to make that easier for you,
0:09:31 > 0:09:33why don't you get it in there? Go on!
0:09:33 > 0:09:35So, what do you think of the diet?
0:09:36 > 0:09:41Honestly, as a doctor, this is not good, Saiful.
0:09:41 > 0:09:43There's a lot of pizza in there.
0:09:43 > 0:09:44- I know.- And chocolate.
0:09:44 > 0:09:47- It's only one piece!- Do you want a bit? I...I...I...
0:09:48 > 0:09:51So there's not exactly your
0:09:51 > 0:09:53- five a day in there, is there? - I know.
0:09:53 > 0:09:56- There's a lot of...- Actually, what is lacking is the fruit content.
0:09:56 > 0:09:57I don't know what happened that week.
0:09:57 > 0:10:00I think I was stressed by these lectures, actually.
0:10:00 > 0:10:01- Yeah.- So, we're nearly done.
0:10:01 > 0:10:03Well done, you two.
0:10:03 > 0:10:06Well done. We've got one more.
0:10:06 > 0:10:08This is it. Ah, thank you.
0:10:08 > 0:10:11Shall we thank them? Thank you very much.
0:10:18 > 0:10:23Right. We're going to try and weigh the amount of food
0:10:23 > 0:10:27that's actually gone in. And it's...
0:10:27 > 0:10:31What's the reading there? It says about 5.5 kilos.
0:10:31 > 0:10:35So that's, roughly, what I've had over a week, so, not too bad.
0:10:35 > 0:10:38Well, yeah, not too bad in terms of quantity.
0:10:38 > 0:10:40Pretty poor in terms of quality, yeah.
0:10:40 > 0:10:42Well, as a scientist, you'd appreciate this.
0:10:42 > 0:10:44I like to do the proper science,
0:10:44 > 0:10:50so not only did we look at the food going in, we also...
0:10:50 > 0:10:56- Oh, no.- We also looked at the food going out!
0:10:57 > 0:11:02So, any volunteers want to help me scrape this in?
0:11:02 > 0:11:03Any volunteers?
0:11:04 > 0:11:05No surprises there.
0:11:05 > 0:11:07Yes, this should be something I should do.
0:11:07 > 0:11:10So, let me do this.
0:11:10 > 0:11:14Look, I know I was famous last year for drinking my own urine,
0:11:14 > 0:11:16but this is really pushing it.
0:11:16 > 0:11:17I mean, really.
0:11:17 > 0:11:19I'm going to use this spoon here.
0:11:19 > 0:11:22So let me try and get it in there.
0:11:22 > 0:11:23Oh, yes.
0:11:25 > 0:11:27Oh, let's get it in!
0:11:28 > 0:11:31Saiful, you've, literally, got me involved in a crap demo here.
0:11:31 > 0:11:32Yes.
0:11:34 > 0:11:35Oh, no.
0:11:36 > 0:11:39It's chocolate! What do you think?
0:11:39 > 0:11:42So, shall we take the reading?
0:11:42 > 0:11:46OK. So you got about one and a half kilo, 1.6 kilos.
0:11:46 > 0:11:48Yeah, and it was...
0:11:48 > 0:11:52And you had just short of five kilos of food in there.
0:11:52 > 0:11:53Yeah, just over five.
0:11:53 > 0:11:55So why the difference?
0:11:55 > 0:11:58Well, so, you've got about five...
0:11:58 > 0:12:03- Let's say five kilos of food and about one and a half kilo of out... - Yes.- ..poo there.
0:12:03 > 0:12:06So, what, we've got sort of three and a half kilos difference.
0:12:06 > 0:12:09And, honestly, most of that food, actually, is water.
0:12:11 > 0:12:12And that's absorbed by your body.
0:12:12 > 0:12:17But then, the rest of it, you use what's in the food,
0:12:17 > 0:12:19the protein in particular, to build your body,
0:12:19 > 0:12:21to build the organs needed to grow you.
0:12:21 > 0:12:25But most of it is used in generating the energy that drives you
0:12:25 > 0:12:27and everything you do. So...
0:12:27 > 0:12:32So there is some point in eating that terrible diet of yours.
0:12:32 > 0:12:37Well, thanks for helping out with this particular slightly unusual demo.
0:12:37 > 0:12:38Thank you, Kevin Fong!
0:12:38 > 0:12:40Yeah, I won't shake your hand.
0:12:40 > 0:12:42Thank you.
0:12:45 > 0:12:47MUSIC PLAYS
0:12:47 > 0:12:49OK, up again, again!
0:12:53 > 0:12:55MUSIC STOPS Right.
0:12:56 > 0:12:58Thank you, Movers And Shakers.
0:12:58 > 0:13:02So, exactly how much energy is in the food we eat?
0:13:03 > 0:13:08Burning food is a bit of a tradition at the Christmas lectures.
0:13:09 > 0:13:13If you look here, they're's Kevin again, doing some burning there.
0:13:15 > 0:13:18It's a good way to find out how much energy food contains.
0:13:18 > 0:13:24So we're going to do something I've called the Great Energy Bake Off.
0:13:24 > 0:13:31So, food has different components and for this I need a lab coat
0:13:31 > 0:13:33and sunglasses.
0:13:33 > 0:13:36So, it's got fat, sugar and protein.
0:13:36 > 0:13:38But I wanted to look at them separately.
0:13:38 > 0:13:43So, to help them burn, we're going to soak them in liquid oxygen.
0:13:43 > 0:13:48So, just to let you know, it's the food's that burning, not the oxygen, OK?
0:13:48 > 0:13:52So, we'll also see...
0:13:52 > 0:13:54I think we've got an infrared camera, that's it over there.
0:13:54 > 0:13:58That's going to monitor the flames given off when I burn these separate
0:13:58 > 0:14:00food types.
0:14:00 > 0:14:01So I've...
0:14:01 > 0:14:04I'm really keen on this torch.
0:14:04 > 0:14:08And we've got some liquid oxygen.
0:14:08 > 0:14:12So we're going to start off with some sugary substance and you can
0:14:12 > 0:14:13see this here.
0:14:13 > 0:14:16So we've got meringue on the left,
0:14:16 > 0:14:20some protein powder in the middle and, lastly, for the fat,
0:14:20 > 0:14:21some pork scratchings.
0:14:21 > 0:14:25OK? Let's start off with the sugar, the meringue.
0:14:25 > 0:14:27OK, so, off you go.
0:14:27 > 0:14:30I'll get this flame, it's a lovely flame...
0:14:30 > 0:14:31Yes, great.
0:14:41 > 0:14:42So it had a bit of a flame.
0:14:43 > 0:14:47So, let's move over to the second one, protein.
0:14:47 > 0:14:48It's a protein powder.
0:14:56 > 0:14:59That was pretty good, wasn't it? Yeah, that was great. So...
0:15:00 > 0:15:03And, then, lastly, the pork scratchings.
0:15:03 > 0:15:04This is our fat.
0:15:07 > 0:15:09So this is our last one.
0:15:20 > 0:15:22Come on, that deserves applause! Come on, yeah!
0:15:26 > 0:15:30Yeah, so this is a replay of the infrared camera and you can see...
0:15:30 > 0:15:32Look at the temperature it's got to.
0:15:33 > 0:15:38That fat went up to 556 Celsius.
0:15:38 > 0:15:40Pretty hot. So...
0:15:41 > 0:15:46So you can tell which one won the Great Energy Bake Off.
0:15:46 > 0:15:48It's clearly the fat.
0:15:50 > 0:15:51But we can usually measure...
0:15:51 > 0:15:54I mean, that's obviously a lovely, lovely display, but we can
0:15:54 > 0:15:57measure energy from burning much more accurately than just using
0:15:57 > 0:15:59the infrared camera.
0:16:00 > 0:16:04So let's look at the values you would get from the different food types.
0:16:04 > 0:16:07And we've got a special energy meter to display that.
0:16:07 > 0:16:09But it's not any old energy meter,
0:16:09 > 0:16:12it's an energy meter in units that, hopefully, you can all understand.
0:16:12 > 0:16:15It's in AA batteries.
0:16:15 > 0:16:18Units are usually kilocalories and kilojoules.
0:16:18 > 0:16:20So for meringue, what do we get?
0:16:20 > 0:16:23So, let's have a look at meringue.
0:16:23 > 0:16:26About 25 AA batteries.
0:16:26 > 0:16:29Protein? Wait, we've got...
0:16:31 > 0:16:33Also 25.
0:16:33 > 0:16:38Lastly, I think you can guess what you will see with fat?
0:16:38 > 0:16:39So, lastly, fat.
0:16:39 > 0:16:41What's the value for fat?
0:16:41 > 0:16:44It's... Look at that.
0:16:44 > 0:16:4756 AA batteries.
0:16:47 > 0:16:49So it's over double the other two.
0:16:49 > 0:16:52We can tell this if you look at the number of kilocalories
0:16:52 > 0:16:55on the packaging of fatty foods.
0:16:55 > 0:16:57They are a lot higher.
0:16:58 > 0:17:02And that's because a kilocalorie is simply a measure of energy.
0:17:02 > 0:17:07I mean, have a look next time you go food shopping or look at the sweets
0:17:07 > 0:17:08and crisps that you eat.
0:17:10 > 0:17:11So not all foods...
0:17:12 > 0:17:18are this energy-rich and not all animals have evolved to eat like us.
0:17:18 > 0:17:22I'd like to introduce you to two very special guests.
0:17:22 > 0:17:25They are strange and exotic creatures,
0:17:25 > 0:17:28but please welcome them a bit quietly, OK?
0:17:28 > 0:17:29So...
0:17:32 > 0:17:35Yes. Aw. SOFT APPLAUSE
0:17:35 > 0:17:38Yes, a gentle clap, that's it, nice.
0:17:38 > 0:17:44OK, this is Faith and this is Bonnie, the goat.
0:17:44 > 0:17:46And the handlers, it's nice to meet you.
0:17:46 > 0:17:48Alice and Tom.
0:17:48 > 0:17:49Thank you for coming in.
0:17:50 > 0:17:54I described them as exotic, perhaps they're not quite exotic,
0:17:54 > 0:17:57but they are remarkable animals.
0:17:57 > 0:18:00It's to do with their digestive system.
0:18:00 > 0:18:04Their digestive system allows them to eat food and access energy that
0:18:04 > 0:18:06we can't, all of us.
0:18:06 > 0:18:09They are called ruminants.
0:18:09 > 0:18:12What would be nice is a volunteer to come down and feed them.
0:18:14 > 0:18:16Yes, do you want to come down?
0:18:17 > 0:18:19Quiet applause. Quiet, quiet.
0:18:20 > 0:18:22Right, can I take your name?
0:18:22 > 0:18:23- Samuel.- Samuel?
0:18:23 > 0:18:26OK, Samuel, you've got some... I think we've got some...
0:18:26 > 0:18:28- Spring greens.- Spring greens. - They are very partial to it.
0:18:28 > 0:18:30If you take a small handful.
0:18:30 > 0:18:35You carry on feeding. So they eat spring greens and they also eat hay,
0:18:35 > 0:18:36as you can see there.
0:18:36 > 0:18:40So how do they break drown that tough material?
0:18:40 > 0:18:43They have a very special extra stomach
0:18:43 > 0:18:46where bacteria ferment their food.
0:18:46 > 0:18:50This breaks down tough plant cells that we can't digest.
0:18:50 > 0:18:51Oh, very sweet.
0:18:53 > 0:18:54They even bring up food...
0:18:55 > 0:18:58..from their stomach back into their mouths,
0:18:58 > 0:19:01so they can actually chew it over and over again!
0:19:01 > 0:19:04I'm not sure if any of you would like to do that.
0:19:04 > 0:19:09But hay has a lot less energy than pork scratchings.
0:19:09 > 0:19:10Faith the sheep...
0:19:11 > 0:19:17..has to eat three kilos of hay a day just to get enough energy to survive.
0:19:18 > 0:19:23And in the fields, she must graze for up to seven hours a day.
0:19:23 > 0:19:26That's a huge amount of time and a huge amount of hay.
0:19:26 > 0:19:30So, let's all thank all of them with a quiet clap.
0:19:30 > 0:19:33So thank you, Alice. Thank you, Tom.
0:19:33 > 0:19:34OK, thank you very much.
0:19:34 > 0:19:36GENTLE APPLAUSE
0:19:36 > 0:19:37OK.
0:19:40 > 0:19:42So if our diet was just hay, that hay there...
0:19:45 > 0:19:48..we'd need to eat four and a half kilos a day
0:19:48 > 0:19:51and mealtime would take for ever.
0:19:51 > 0:19:53Can you imagine munching through all that?
0:19:53 > 0:19:55AUDIENCE LAUGH
0:19:55 > 0:19:56Oh, no!
0:19:58 > 0:19:59That's OK.
0:20:00 > 0:20:04So the high energy density of our food is one of the key factors in
0:20:04 > 0:20:07how humans have time to do all the things we are really good at.
0:20:09 > 0:20:14We've done the sums and I'll show you the results on our energy meter
0:20:14 > 0:20:15while I jump over those.
0:20:16 > 0:20:17So, for example...
0:20:19 > 0:20:23..if we want to play the piano for an hour, it's...
0:20:26 > 0:20:30It's going to be 91 AA batteries.
0:20:30 > 0:20:32That's in an hour.
0:20:32 > 0:20:35If standing up and painting takes...
0:20:38 > 0:20:41..152 AA batteries.
0:20:42 > 0:20:48Just walking in an hour takes... Let's have a look at walking.
0:20:48 > 0:20:51..127 AA batteries.
0:20:51 > 0:20:55So where does all the energy in the food that I ate earlier on,
0:20:55 > 0:20:57where does it all come from?
0:20:57 > 0:21:00There's a fundamental principle...
0:21:00 > 0:21:01of energy.
0:21:01 > 0:21:04You can't create it or destroy it.
0:21:04 > 0:21:08It can only be converted from one form to another.
0:21:08 > 0:21:11So the food itself must have got its energy from somewhere.
0:21:11 > 0:21:14So let's follow the chain of energy and find out.
0:21:14 > 0:21:18And to show you, I've got another exotic creature.
0:21:22 > 0:21:23A salmon.
0:21:25 > 0:21:27It's a bit of a violent salmon.
0:21:27 > 0:21:30So this salmon wasn't part of my weekly diet,
0:21:30 > 0:21:32where does the salmon get its energy from?
0:21:32 > 0:21:35For this, I need three volunteers.
0:21:35 > 0:21:36Maybe someone from this side.
0:21:36 > 0:21:41Yourself, there, and one in green and one final one.
0:21:41 > 0:21:44Yes, the one in the blue T-shirt. Yeah, come on down.
0:21:45 > 0:21:47- So, hello there.- Hello.- Can I take your name?- Lizzie.
0:21:47 > 0:21:49Lizzie. Can I take your name?
0:21:49 > 0:21:51- Isaac.- Isaac.
0:21:51 > 0:21:53- And what's your name?- Omar.- Omar.
0:21:53 > 0:21:57OK, I'm going to put you in height order.
0:21:57 > 0:22:00So if you go that side, you go on that side
0:22:00 > 0:22:02and if you come across there.
0:22:02 > 0:22:03So get in a straight line, OK.
0:22:03 > 0:22:06We want a nice, clear picture of you.
0:22:06 > 0:22:11So, I'm going to get you to hold the lovely salmon, OK?
0:22:11 > 0:22:13All right, so this is a bit of a food chain,
0:22:13 > 0:22:15so we want to see, really,
0:22:15 > 0:22:18where these different creatures get their food from.
0:22:18 > 0:22:21So I would like you to reach in there.
0:22:21 > 0:22:23So, what does a salmon eat?
0:22:23 > 0:22:24A salmon eats...
0:22:24 > 0:22:28Put your hand in the mouth and pull out what the salmon eats.
0:22:28 > 0:22:30It eats, basically, smaller fish.
0:22:30 > 0:22:33And, in this case, it's just a mackerel.
0:22:33 > 0:22:36But, what does mackerel get its energy from?
0:22:36 > 0:22:39From its food. So why don't you stick your hand in there
0:22:39 > 0:22:41and see what you can pull out. Yes.
0:22:41 > 0:22:44That is phytoplankton, OK?
0:22:44 > 0:22:46A good representation of phytoplankton.
0:22:46 > 0:22:52So, phytoplankton is just very tiny marine plants, but like all plants,
0:22:52 > 0:22:55Well, they get their energy from the sun.
0:22:55 > 0:23:00So you can follow the same chain of energy for almost any food type
0:23:00 > 0:23:02and any food you choose.
0:23:02 > 0:23:05But it always ends up at the sun.
0:23:06 > 0:23:11So every single bite of food we take is, effectively, solar powered.
0:23:11 > 0:23:12Great, well, thank you, all three of you.
0:23:12 > 0:23:15Thank you for coming on. So let's thank them again.
0:23:19 > 0:23:23Right. But it's not just our food source that is important.
0:23:23 > 0:23:25It's our size as well.
0:23:27 > 0:23:32So, let me get this out.
0:23:32 > 0:23:39So here we have a mouse.
0:23:40 > 0:23:43Sadly, it's ex-mouse.
0:23:45 > 0:23:48Well, these are the "X-MOUSE lectures".
0:23:50 > 0:23:52AUDIENCE GROANS Oh...!
0:23:52 > 0:23:56So, unfortunately, we wanted to use a real mouse,
0:23:56 > 0:24:00but we were a bit scared that it might actually die of shock,
0:24:00 > 0:24:02seeing you lot.
0:24:02 > 0:24:07But it's... The reason I wanted to bring out this mouse is that it eats
0:24:07 > 0:24:14about a third of its own body weight every single day, just to stay alive.
0:24:14 > 0:24:18If we humans ate a third of our body weight today,
0:24:18 > 0:24:19what would it look like?
0:24:22 > 0:24:29It would mean eating about 150 cheeseburgers a day
0:24:29 > 0:24:31if we were equivalent to that mouse.
0:24:31 > 0:24:37The difference is that really small animals, like this wee mouse,
0:24:37 > 0:24:41has to eat a lot more than larger mammals per unit weight.
0:24:41 > 0:24:48And that's because the mouse has a relatively large surface area compared
0:24:48 > 0:24:50to the volume of their body.
0:24:50 > 0:24:54So this means they lose a lot more energy as heat.
0:24:54 > 0:24:57So, in this case, size does matter.
0:24:57 > 0:25:00OK? MUSIC PLAYS
0:25:10 > 0:25:12MUSIC STOPS
0:25:12 > 0:25:15You're doing really well there.
0:25:15 > 0:25:20So, earlier, we saw that burning food releases its energy.
0:25:20 > 0:25:24But we, obviously, don't actually burn food inside our bodies.
0:25:24 > 0:25:31So how do we turn something like that salmon into energy that we can use?
0:25:31 > 0:25:37So, I'm a chemist and, thankfully, a lot of this is chemistry.
0:25:37 > 0:25:42So up on the screen is something I'd never thought I'd see.
0:25:43 > 0:25:47This is the view of my own, I stress my own,
0:25:47 > 0:25:50lower intestine from the inside.
0:25:51 > 0:25:54To get this image I had to swallow a very clever device,
0:25:54 > 0:25:55a very special device.
0:25:55 > 0:25:58This isn't the actual one, but it looks a bit like this.
0:26:00 > 0:26:03If you have a look. That is what is called a capsule endoscope.
0:26:04 > 0:26:10And, essentially, it takes photos of my inside in real-time as it was
0:26:10 > 0:26:11going through the body.
0:26:13 > 0:26:17So I had to starve myself for two days to get a clear image.
0:26:17 > 0:26:19So let's go back to the beginning of the footage
0:26:19 > 0:26:21and let me talk you through what happens.
0:26:21 > 0:26:23You can see these are my fingers.
0:26:23 > 0:26:25I'm holding the capsule.
0:26:25 > 0:26:26And I'm, actually...
0:26:26 > 0:26:31There's my teeth. You can see it just passed my tongue and off it
0:26:31 > 0:26:34goes down that clear channel.
0:26:34 > 0:26:39And it's gone straight... Actually, the guy who was operating it at the local hospital said it went
0:26:39 > 0:26:42down really quickly. I really had starved myself.
0:26:42 > 0:26:45So it went down into the lower intestine and there it is.
0:26:45 > 0:26:48Usually you see lots of kind of food along the way.
0:26:48 > 0:26:53So what is happening within my mouth and in the stomach?
0:26:53 > 0:26:55Well, it's basically some chemistry.
0:26:55 > 0:27:01There are some enzymes that break down complex molecules.
0:27:01 > 0:27:05And they break them down into sugar, called glucose.
0:27:05 > 0:27:09And in my lower intestine that glucose goes across the intestinal walls
0:27:09 > 0:27:11straight into my blood.
0:27:11 > 0:27:14So the blood carries the glucose into muscles and organs
0:27:14 > 0:27:18where it reacts again to give them energy.
0:27:19 > 0:27:23I should say we stopped the image there.
0:27:23 > 0:27:24I didn't want you to see...
0:27:25 > 0:27:29..the light at the end of the tunnel, so to speak, yes.
0:27:29 > 0:27:32MUSIC PLAYS Off you go. Yes, keeping them fit.
0:27:32 > 0:27:34That's it. I'm going to join in this time.
0:27:37 > 0:27:39Very good.
0:27:42 > 0:27:44MUSIC STOPS
0:27:44 > 0:27:48HUGH SNORES OK, so we've just had some really active people,
0:27:48 > 0:27:52so I think it's time to catch in on Hugh.
0:27:52 > 0:27:54Hugh, how are you doing?
0:27:54 > 0:27:57HUGH CONTINUES TO SNORE
0:27:59 > 0:28:03Right, so what does this mean for our performance?
0:28:03 > 0:28:06Can we supercharge ourselves using sugar?
0:28:08 > 0:28:10The answer is...sort of.
0:28:10 > 0:28:15Sugar gives you that quick burst of energy, that sugar buzz.
0:28:15 > 0:28:19That can be useful if you are doing a lot of exercise.
0:28:19 > 0:28:23There's a reason obviously that you don't see Andy Murray snacking on
0:28:23 > 0:28:24pork scratchings between games.
0:28:26 > 0:28:30But, sugar, as you probably know, has its downsides, too.
0:28:31 > 0:28:35Those spikes, or that rise in sugar levels in the blood,
0:28:35 > 0:28:38aren't good for you long-term.
0:28:38 > 0:28:40And if you take in a lot of sugar...
0:28:41 > 0:28:44..it could end up being stored.
0:28:44 > 0:28:49And so how does the body store some excess energy?
0:28:49 > 0:28:55Well, we got a bit of a favour from a local clinic and they kindly
0:28:55 > 0:28:56allowed me to borrow...
0:28:58 > 0:29:01..some real human fat.
0:29:02 > 0:29:05That is real. It weighs about a kilo.
0:29:05 > 0:29:08It looks a bit red because of the blood in there.
0:29:08 > 0:29:12But how much energy is in that kilo of human fat?
0:29:12 > 0:29:14So let's go over to the energy meter to give you an indication.
0:29:16 > 0:29:20So, that kilo goes up to...
0:29:20 > 0:29:22Yes, a massive amount.
0:29:22 > 0:29:29That kilo has 1,869 AA batteries of energy.
0:29:30 > 0:29:35That's a lot, you know, much greater than the stuff I showed you before.
0:29:35 > 0:29:38It would power me for three to four days.
0:29:40 > 0:29:45So, this reminds us that humans are energy storage machines as well as
0:29:45 > 0:29:47energy conversion machines.
0:29:47 > 0:29:51So, someone like me, you might be surprised to know,
0:29:51 > 0:29:52although you saw my diet earlier,
0:29:52 > 0:29:57I have about ten times this beaker of fat on my body.
0:29:58 > 0:30:02It means that if I was on one of those survival programmes,
0:30:02 > 0:30:06I would survive up to several weeks without eating.
0:30:08 > 0:30:12But long-term, we obviously need to strike a balance
0:30:12 > 0:30:14between the amount of energy we take in
0:30:14 > 0:30:17and the amount of energy we use up.
0:30:17 > 0:30:22Otherwise, that excess energy leads to getting us overweight.
0:30:22 > 0:30:27So, does our body generate any other forms of energy from our food?
0:30:28 > 0:30:32We've talked about heat, we've talked about movement,
0:30:32 > 0:30:35but there is something else.
0:30:35 > 0:30:40The human body is far more electric than you might think.
0:30:40 > 0:30:46To show this, I need a volunteer to help me play a little game.
0:30:46 > 0:30:48Yes, if you could come down, in green? Yes.
0:30:51 > 0:30:53- Can I take your name?- Isabella.
0:30:53 > 0:30:55Isabella. This is Isabella.
0:30:55 > 0:30:59And while Isabella's getting hooked up, I'll explain what's going on.
0:31:02 > 0:31:07This kind of equipment here allows someone like Isabella to control
0:31:07 > 0:31:11someone else's actions using the power of electricity.
0:31:13 > 0:31:15And she's going to get wired up.
0:31:16 > 0:31:17On the other end,
0:31:17 > 0:31:20I haven't asked another volunteer because it can be a bit weird and
0:31:20 > 0:31:24feel a bit uncomfortable but it's a great pleasure...
0:31:24 > 0:31:29to introduce and invite the 2013 Christmas lecturer to help out.
0:31:29 > 0:31:31Professor Alison Woollard.
0:31:33 > 0:31:35Hi, there, Alison.
0:31:35 > 0:31:37- Hi, good to see you.- Nice to see you.
0:31:39 > 0:31:42Thank you, Alison, for joining us and helping out.
0:31:42 > 0:31:45What's it feel like, being back here in the lecture theatre again?
0:31:45 > 0:31:48It feels great to be back, but not in the driving seat!
0:31:48 > 0:31:51OK. So, what we're going to do, we've got a cup of water.
0:31:51 > 0:31:52OK.
0:31:54 > 0:31:56Why don't you just take a sip now?
0:31:56 > 0:31:59- Sip, right, OK.- Because we're going to show...
0:31:59 > 0:32:00- No tricks?- No tricks yet.
0:32:02 > 0:32:04That's fine, that's nice and clear.
0:32:04 > 0:32:06So, Alison, if you want to show us what they've done to you outside.
0:32:06 > 0:32:08Yeah, they've put these stickers on me.
0:32:08 > 0:32:11OK, and they're all fine, nothing painful?
0:32:11 > 0:32:13- Yeah, no, no.- So, what James is going to do,
0:32:13 > 0:32:14he's going to hook you up.
0:32:14 > 0:32:16We're not going to get started yet.
0:32:18 > 0:32:22So, basically, now we're connecting Isabella to Alison.
0:32:22 > 0:32:25So we're going to maybe do a bit of a test at the moment.
0:32:25 > 0:32:28It's not on, I don't think it's on.
0:32:28 > 0:32:31Why don't you try and clench your fist and see if it affects her.
0:32:31 > 0:32:32No, nothing's going on.
0:32:32 > 0:32:38So, the point is that when I switch this on, Isabella, in principle,
0:32:38 > 0:32:40and hopefully in practice,
0:32:40 > 0:32:45can actually stop Alison having another cup of water.
0:32:45 > 0:32:47So if you pick that up.
0:32:47 > 0:32:49- OK.- Let's have a bit of a drumroll.
0:32:50 > 0:32:53OK, off you go. Try drinking the water.
0:32:55 > 0:32:57Oh, my goodness!
0:32:57 > 0:33:00- Move it!- Agh!
0:33:00 > 0:33:02Right, you can stop now.
0:33:02 > 0:33:04I'm going to turn it down.
0:33:04 > 0:33:08So, Alison, looks like you've got a bit of a drinking problem!
0:33:08 > 0:33:09I certainly have, yeah!
0:33:09 > 0:33:11Right, so how did that feel?
0:33:11 > 0:33:13Well, it felt very weird.
0:33:13 > 0:33:14So I felt sort of sparks here,
0:33:14 > 0:33:16like a bit of an electric shock and
0:33:16 > 0:33:18then, my fingers went completely mad.
0:33:18 > 0:33:19I had no control over them at all.
0:33:19 > 0:33:21- Was it painful?- No, not really.
0:33:21 > 0:33:24- Just weird.- I haven't tried this yet so I don't know what it feels like.
0:33:24 > 0:33:25But I want to try it later.
0:33:25 > 0:33:28Feels really weird, yeah. I'm not usually so easy to control!
0:33:28 > 0:33:33So, Alison, I know you're a biologist and we have discussed this.
0:33:33 > 0:33:35So, tell me, what is actually happening?
0:33:35 > 0:33:37What is happening between Isabella and you?
0:33:37 > 0:33:43Well, our neurons have evolved this remarkable ability to conduct electricity.
0:33:43 > 0:33:45So when a neuron or a nerve is activated,
0:33:45 > 0:33:47like we're doing here artificially,
0:33:47 > 0:33:51it causes a difference in the voltage across the membrane.
0:33:51 > 0:33:54And, so, really, our neurons are tiny, tiny little batteries.
0:33:54 > 0:33:58And this difference in voltage triggers a wave of electricity that travels all
0:33:58 > 0:34:01the way down the neurons until it encounters muscle and it causes
0:34:01 > 0:34:04the muscle cells to contract, like the ones in my fist.
0:34:04 > 0:34:06And that stimulates the movement.
0:34:06 > 0:34:09So, do they know how fast that signal travels?
0:34:09 > 0:34:13Well, up to about 250 mph, so about the speed of a Formula One car.
0:34:13 > 0:34:15- That's pretty fast.- Very fast.
0:34:15 > 0:34:17So that's why that transfer was so speedy?
0:34:17 > 0:34:19Exactly, yes.
0:34:19 > 0:34:20Obviously, that was a fun demo,
0:34:20 > 0:34:25but there are more quite serious applications of this kind of technology.
0:34:25 > 0:34:28Amputees, people who have lost their limbs,
0:34:28 > 0:34:31can, actually, control their prosthetic limbs using the power
0:34:31 > 0:34:34of electricity, a bit like this.
0:34:34 > 0:34:37So, we're going to do one more demo.
0:34:37 > 0:34:39We don't need a drumroll this time.
0:34:39 > 0:34:42So don't do it yet. And, Alison, sorry about this!
0:34:42 > 0:34:45- Maximum discomfort.- Yeah, I know! We're going to let you do it again.
0:34:45 > 0:34:47So thanks for being such a sport.
0:34:47 > 0:34:51So, OK. Go on, Isabella. We're going to try and stop Alison drinking again.
0:34:51 > 0:34:52- Whoa...!- Go on, you do it.
0:34:52 > 0:34:55- Oh, no! All over her nice dress. - Oh, no, no, no.
0:34:55 > 0:34:56Oh, no.
0:34:56 > 0:34:58I'll turn it down.
0:34:58 > 0:35:01Right, I think we should give Alison a hand.
0:35:01 > 0:35:02OK!
0:35:07 > 0:35:09So, how much electricity do we generate?
0:35:10 > 0:35:16A single nerve firing produces a very small amount of electricity.
0:35:16 > 0:35:21We have well over 80 billion nerves in our brains alone.
0:35:21 > 0:35:25That's eight with ten zeros after it.
0:35:25 > 0:35:31This adds up to enough electricity to charge a smartphone in about 70 hours.
0:35:31 > 0:35:33So, of course,
0:35:33 > 0:35:38we won't be plugging phones into our brains any time soon.
0:35:38 > 0:35:41So we can use technology to generate electricity from our bodies,
0:35:41 > 0:35:44but what about our bodies themselves?
0:35:44 > 0:35:49How good are they at converting and generating energy?
0:35:49 > 0:35:53How powerful are we and how do we compare to something like a machine?
0:35:55 > 0:35:57There's only one way to find out.
0:35:57 > 0:36:01Let's pit them against each other, let's have a fight!
0:36:01 > 0:36:03OK, so we need a professional for this.
0:36:03 > 0:36:08So, please welcome Britain's human-powered land speed record holder,
0:36:08 > 0:36:09Ken Buckley!
0:36:16 > 0:36:17- Hi.- Hi, there.
0:36:21 > 0:36:24So, Ken, you've got this record. Tell us more about this record,
0:36:24 > 0:36:26what does the record mean?
0:36:26 > 0:36:29So, it's the British land speed record for human-powered vehicles.
0:36:29 > 0:36:33So, basically, as fast as you can get a human-powered bicycle to go.
0:36:33 > 0:36:35OK, so how fast did you get?
0:36:35 > 0:36:39So we did a top speed of 76.6 miles an hour.
0:36:39 > 0:36:43So tell me about the training you need to get to that kind of speed,
0:36:43 > 0:36:45what kind of training do you need to do?
0:36:45 > 0:36:50So, I do about 15-20 hours a week, mostly on the bike,
0:36:50 > 0:36:53some in the gym and a lot of stretching and yoga and other stuff as well.
0:36:53 > 0:36:55OK. So, what we got here,
0:36:55 > 0:36:59we got your bike and we've hooked it up to an electrical generator.
0:36:59 > 0:37:01An electrical generator with a difference.
0:37:01 > 0:37:05We've got it connected up to some devices, so we've got some lights,
0:37:05 > 0:37:09we've got a blender and we've got a kettle here.
0:37:09 > 0:37:16And we're going to see if the human machine can help to power some real machines. OK?
0:37:16 > 0:37:21So we're going to get our top athlete. So...
0:37:21 > 0:37:23I think we need a bit of a drumroll for this, don't we?
0:37:23 > 0:37:26So let's have a little drumroll, and off you go.
0:37:29 > 0:37:33So, you can see the lights coming on, so that's straightforward.
0:37:33 > 0:37:36So lights don't need that much energy.
0:37:36 > 0:37:38So let's see if we've got the blender.
0:37:40 > 0:37:41Blender, no problem.
0:37:43 > 0:37:46For the kettle, it's very difficult to monitor the kettle,
0:37:46 > 0:37:48so we've got an infrared camera.
0:37:48 > 0:37:49OK?
0:37:50 > 0:37:54So we got the kettle coming on, and that's the tough one.
0:37:54 > 0:37:56So this is the temperature of the kettle,
0:37:56 > 0:38:0021.6 degrees, so it's cold water
0:38:00 > 0:38:01or warm water.
0:38:01 > 0:38:03So let's see if it goes up.
0:38:04 > 0:38:06No.
0:38:06 > 0:38:08Can you get to 100 degrees?
0:38:08 > 0:38:10THEY LAUGH
0:38:11 > 0:38:13OK, thanks, Ken, let's stop there.
0:38:13 > 0:38:14Let's give him applause.
0:38:22 > 0:38:24So, as you can see,
0:38:24 > 0:38:26it was easy to get to the lights and the blender
0:38:26 > 0:38:29but that boiling a kettle needed a lot of energy.
0:38:29 > 0:38:31And...I think you're hotter than the kettle!
0:38:31 > 0:38:33Yeah, that's about right, yeah.
0:38:33 > 0:38:36Actually, let's put the thermal camera on Ken.
0:38:36 > 0:38:38Let's see how he's looking. Look at that.
0:38:38 > 0:38:41Let's compare it to me, and I haven't been doing anything!
0:38:41 > 0:38:43That looked like tough work.
0:38:43 > 0:38:44- Yeah, that was hard.- Yes.
0:38:44 > 0:38:46- OK, thank you.- Thanks very much.
0:38:51 > 0:38:53At their absolute peak,
0:38:53 > 0:38:58a highly trained professional can't even boil a kettle.
0:38:58 > 0:39:02So, compared to some common machines, we're not very powerful.
0:39:02 > 0:39:06So, can we improve our performance for the same amount of energy?
0:39:06 > 0:39:08Can we supercharge ourselves?
0:39:09 > 0:39:15To find out, I'd like you to welcome the 2010 Christmas lecturer,
0:39:15 > 0:39:17Professor Mark Miodownik.
0:39:20 > 0:39:21- Great.- Thank you.
0:39:26 > 0:39:28OK, Mark, can you come down here?
0:39:28 > 0:39:32So, Mark, what's it like to be back in the lecture theatre?
0:39:32 > 0:39:35I can honestly say I would not rather be anywhere else.
0:39:35 > 0:39:37Absolutely. I don't blame you.
0:39:37 > 0:39:40And if you've just watched our cycling generator,
0:39:40 > 0:39:41how do you think you'd fare?
0:39:41 > 0:39:43Do you exercise much?
0:39:43 > 0:39:45It's mostly brainpower, I have to admit.
0:39:45 > 0:39:47Yep. I sit.
0:39:47 > 0:39:50- You sit.- I sit. I look.- Do you do sports at all?
0:39:50 > 0:39:51I cycle to work.
0:39:51 > 0:39:55- Cycle to work? All right. OK.- I was looking at the cycling there thinking, "I could do that."
0:39:55 > 0:40:00Oh, right. Well, what if we use these running machines to pit you against Ken,
0:40:00 > 0:40:02our cycling land speed record holder?
0:40:02 > 0:40:05Let's bring him on. Ken, are you there?
0:40:08 > 0:40:10- Hi there, Ken, again.- Hi, there. - Hello.- This is Mark.
0:40:10 > 0:40:13- Hi, Mark.- How's it going?
0:40:13 > 0:40:15So, we're going to do an experiment.
0:40:15 > 0:40:18We just want to see how much energy you're going to use,
0:40:18 > 0:40:20so we're going to start getting you kitted out.
0:40:20 > 0:40:23So, if you could both get on to the treadmills...
0:40:23 > 0:40:27What we have here is obviously a couple of treadmills,
0:40:27 > 0:40:30but they are connected up to some monitors.
0:40:30 > 0:40:33And they are going to be putting on some masks.
0:40:33 > 0:40:35These masks all connect to a Vox machine.
0:40:35 > 0:40:37What it does is it measures...
0:40:38 > 0:40:40And you can see on the screens there,
0:40:40 > 0:40:46it measures the amount of oxygen that you take in and the amount
0:40:46 > 0:40:48of oxygen is given out.
0:40:48 > 0:40:52And why that's useful is that you can actually relate it directly
0:40:52 > 0:40:55to the amount of energy used.
0:40:55 > 0:40:58The energy expenditure, and that's the two Es you see on
0:40:58 > 0:41:00those two monitors.
0:41:00 > 0:41:03And we're just going to compare the two...
0:41:04 > 0:41:08..so before they get going, a simple question.
0:41:10 > 0:41:15Who thinks that Mark will be using more energy than Ken?
0:41:15 > 0:41:17Hands up. OK.
0:41:17 > 0:41:20So, who thinks that Ken will be using the more energy?
0:41:22 > 0:41:27Interesting. Right. So let's get the treadmills started.
0:41:27 > 0:41:28OK. Off they go.
0:41:32 > 0:41:35OK. So let's see how they're doing.
0:41:37 > 0:41:39There is a difference already between the two,
0:41:39 > 0:41:41quite a significant difference.
0:41:42 > 0:41:44So let's let it run for a bit,
0:41:44 > 0:41:48see if we can tire out Mark just from walking.
0:41:49 > 0:41:51If I knew you were going to do this to me
0:41:51 > 0:41:54I wouldn't have worn a three-piece suit, you know.
0:41:56 > 0:41:58OK. So let's begin to wind down.
0:41:58 > 0:42:01Shall we stop now? OK. Let's stop them both.
0:42:03 > 0:42:05So you can see, if you look at the numbers...
0:42:07 > 0:42:10..Ken is actually using more energy than Mark...
0:42:11 > 0:42:12..which is interesting.
0:42:12 > 0:42:14I have to say,
0:42:14 > 0:42:18Ken has more muscle than you, Mark and that is the main reason.
0:42:18 > 0:42:20Ken being more muscular...
0:42:20 > 0:42:22he needs more energy to move.
0:42:22 > 0:42:28That's because his body has adapted to both consuming and generating more energy.
0:42:28 > 0:42:33As with everything to do with energy, you don't get a free lunch,
0:42:33 > 0:42:34so, this, here...
0:42:34 > 0:42:36Ooh! Nearly came off.
0:42:36 > 0:42:38This is...
0:42:38 > 0:42:41When Ken's training, this is his daily diet.
0:42:41 > 0:42:45So Ken, being an athlete, is definitely supercharged.
0:42:45 > 0:42:48Ken can do more work than most of us.
0:42:48 > 0:42:53So let's thank Mark and Ken for doing this demonstration.
0:42:53 > 0:42:54Thank you.
0:42:55 > 0:42:59Thank you. Mark, thank you. Thanks for coming on.
0:42:59 > 0:43:02MUSIC PLAYS
0:43:07 > 0:43:09MUSIC STOPS
0:43:09 > 0:43:11Yes. Well done.
0:43:11 > 0:43:13Some good moves there, actually.
0:43:13 > 0:43:14So let's catch in on Hugh.
0:43:14 > 0:43:15How're you doing, Hugh?
0:43:15 > 0:43:18HUGH SNORES
0:43:21 > 0:43:23He looks very comfortable.
0:43:23 > 0:43:24We'll come back to him.
0:43:24 > 0:43:28So, there are ways to supercharge our bodies and improve our performance.
0:43:28 > 0:43:30It's called training.
0:43:32 > 0:43:35What about increasing performance without training?
0:43:35 > 0:43:36Is that possible?
0:43:36 > 0:43:40There's a drug that many athletes take to increase their performance.
0:43:40 > 0:43:46It gives them better reaction times and helps them with their fatigue.
0:43:46 > 0:43:47It used to be banned...
0:43:48 > 0:43:53..but use was so widespread it's now become legal and I'm going to take
0:43:53 > 0:43:56some right now, live on this stage tonight.
0:43:56 > 0:43:58The drug is caffeine.
0:43:58 > 0:44:00And, actually, I need some.
0:44:02 > 0:44:03That's nice and hot.
0:44:05 > 0:44:07So I was thinking about how to show you the effects
0:44:07 > 0:44:09of caffeine on reaction times.
0:44:09 > 0:44:13So please welcome my warm-up man, Matt.
0:44:18 > 0:44:19- Good to see you.- Good to see you.
0:44:22 > 0:44:27So, Matt, I understand we got you to do something that was a bit difficult.
0:44:27 > 0:44:30We asked you to give up caffeine.
0:44:30 > 0:44:31- Yes.- For how long?
0:44:31 > 0:44:33Well, even though I do love my coffee,
0:44:33 > 0:44:38somehow you convinced me to go for two weeks completely decaffeinated.
0:44:38 > 0:44:44- So, no coffee?- No coffee, no chocolates, no tea, it's been a nightmare.
0:44:44 > 0:44:45So you are completely decaffeinated.
0:44:45 > 0:44:48I'm absolutely decaffeinated, my goodness.
0:44:48 > 0:44:51With that decaffeinated state, what did we do to you?
0:44:51 > 0:44:53We thought we'd test your reaction times.
0:44:53 > 0:44:56- Yes.- So you can tell us more about this.
0:44:56 > 0:44:58This is a BATAK machine, I believe.
0:44:58 > 0:45:00- Yes.- What did we get you to do?
0:45:00 > 0:45:05This tests your reaction times by lighting up these different letters
0:45:05 > 0:45:10and numbers, and you've got to hit the one that's lit up as fast as you can
0:45:10 > 0:45:15and then that repeats, as some form of unusual psychological torture, for about 30 seconds.
0:45:15 > 0:45:17So I think we might have some footage.
0:45:17 > 0:45:20Do we have some footage of you doing something earlier?
0:45:20 > 0:45:22- Yes.- So talk us through it.
0:45:22 > 0:45:24- So there you are.- So there I am,
0:45:24 > 0:45:26this is me without caffeine at all for two weeks
0:45:26 > 0:45:28and I'm doing, can't even find it, there it is,
0:45:28 > 0:45:32I'm doing my best to hit the lights as fast as I can and I'm doing poorly.
0:45:32 > 0:45:35I think we've given you some coffee since then.
0:45:35 > 0:45:37Have we? We've given you some coffee?
0:45:37 > 0:45:39Yes, so since that was recorded,
0:45:39 > 0:45:41I was allowed coffee for the first time in two weeks.
0:45:41 > 0:45:44I've had three coffees since that happened
0:45:44 > 0:45:47and my brain suddenly feels alive again.
0:45:47 > 0:45:50So what was the results from that...?
0:45:50 > 0:45:55- 29 buzzers hit in 30 seconds.- 29?
0:45:55 > 0:45:57Fewer than one a second.
0:45:57 > 0:45:59That's me enjoying my coffee,
0:45:59 > 0:46:01when we were getting ready for the recording.
0:46:01 > 0:46:04- I love it.- Really enjoying it. - Yeah, I know. Really enjoying it.
0:46:06 > 0:46:10So we're going to, actually, test Matt again, after that,
0:46:10 > 0:46:11after he's had the coffee.
0:46:11 > 0:46:15So why don't you get into position, but don't start yet.
0:46:15 > 0:46:18Get into position. I think you know how to start it off, do you?
0:46:18 > 0:46:22Yeah, I hit E and it all breaks off.
0:46:22 > 0:46:26So I think this really does deserve a super-duper drumroll from
0:46:26 > 0:46:27everybody, so come on.
0:46:30 > 0:46:31And go.
0:47:02 > 0:47:04- MACHINE:- 'Time up.'
0:47:04 > 0:47:06Yes. Yeah!
0:47:11 > 0:47:16I have to congratulate you, what an improvement.
0:47:16 > 0:47:19What an improvement. So that caffeine really had an effect there.
0:47:19 > 0:47:21- I feel alive.- You feel alive.
0:47:21 > 0:47:23So how did it feel that time?
0:47:23 > 0:47:27Amazing. Like everything narrowed in and I was just seeing the machine,
0:47:27 > 0:47:30seeing the lights and I was almost moving before I was thinking.
0:47:30 > 0:47:32OK, well, let's thank Matt once more.
0:47:32 > 0:47:35Thank you. Thanks a lot.
0:47:41 > 0:47:46Obviously, that was just a demonstration, it was a sample of one,
0:47:46 > 0:47:51but there are proper scientific studies with larger sample sizes that have
0:47:51 > 0:47:56shown that caffeine does have a very strong effect on performance.
0:47:56 > 0:47:58It increases activity in the brain
0:47:58 > 0:48:02and tricks the body into releasing adrenaline.
0:48:03 > 0:48:08It can improve your reaction times by up to 10% and even reduces
0:48:08 > 0:48:09your feeling of fatigue.
0:48:10 > 0:48:12But caffeine is no wonder drug.
0:48:14 > 0:48:17The increase in performance is tiny...
0:48:18 > 0:48:25..but those tiny margins can make a big difference for professional athletes.
0:48:25 > 0:48:29But, obviously, it's not going to make me Mo Farah.
0:48:29 > 0:48:35So, so far, we've looked mostly at improving the way our bodies use energy...
0:48:36 > 0:48:38..but can we look at food itself?
0:48:39 > 0:48:43Earlier, we worked out how much energy was in each food type...
0:48:45 > 0:48:49..but that didn't include how much energy it took to produce that food
0:48:49 > 0:48:51in the first place.
0:48:51 > 0:48:55So can we produce food more efficiently?
0:48:55 > 0:48:56So here's...
0:48:57 > 0:48:59..another cheeseburger, here.
0:49:01 > 0:49:04We can do the calculations.
0:49:04 > 0:49:09Did you know that each burger takes the equivalent of ten burgers' worth
0:49:09 > 0:49:10of energy...
0:49:12 > 0:49:13..to produce?
0:49:13 > 0:49:16So all this to produce that.
0:49:16 > 0:49:17That's a lot.
0:49:19 > 0:49:21So why is it so much?
0:49:21 > 0:49:27Well, wheat to produce bread needs irrigation and takes electricity,
0:49:27 > 0:49:28but it's the meat...
0:49:29 > 0:49:31..that takes the most energy to produce.
0:49:31 > 0:49:38So better take this away before our next beautiful guests come on...
0:49:39 > 0:49:43..so this is, definitely, a very quiet welcome.
0:49:43 > 0:49:45In fact, it probably doesn't need any applause.
0:49:57 > 0:49:58So...
0:50:01 > 0:50:04This...
0:50:04 > 0:50:06this...
0:50:06 > 0:50:10this is Inky Minx here on your left,
0:50:10 > 0:50:16and her baby is with her, and she's called Jet, and the handlers.
0:50:16 > 0:50:19Thank you very much, Felicity, and thanks for coming along.
0:50:19 > 0:50:21Oh, aren't they lovely?
0:50:23 > 0:50:27Obviously, to get to this size, Inky would have had to have eaten
0:50:27 > 0:50:32about 2,025 kilos of grain.
0:50:32 > 0:50:34We've got the real stuff now.
0:50:34 > 0:50:36So, in general...
0:50:36 > 0:50:39Actually, I think Inky has to...
0:50:39 > 0:50:40close her ears, doesn't she?
0:50:40 > 0:50:46In general, to produce just one kilo of beef takes seven kilos of grain,
0:50:46 > 0:50:50and growing grain requires fertiliser, irrigation and transport.
0:50:51 > 0:50:55So, in pure energy terms, this isn't a very good trade.
0:50:56 > 0:51:01I have to thank the handlers and Inky Minx and their beautiful little...
0:51:02 > 0:51:03..calf to come in.
0:51:03 > 0:51:05So thank you very much for coming in.
0:51:05 > 0:51:07Thank you.
0:51:19 > 0:51:22Cows also produce something else from their food.
0:51:22 > 0:51:24Let's see that with a simple demonstration.
0:51:26 > 0:51:29So this is a bag or a balloon
0:51:29 > 0:51:33that contains the same amount of methane gas
0:51:33 > 0:51:37that Inky produces every single minute.
0:51:37 > 0:51:41Actually, about the time she was in the lecture theatre.
0:51:41 > 0:51:45So did you know most of this comes from burps, or up-windies,
0:51:45 > 0:51:46as my children call them.
0:51:46 > 0:51:51This balloon contains a lot of energy that normally goes into
0:51:51 > 0:51:53the atmosphere.
0:51:53 > 0:51:54Shall we take it away...
0:51:55 > 0:51:58..or set it alight? AUDIENCE: Set it alight!
0:51:58 > 0:52:03Thank you. I've got a pyrotechnic expert to do this for us.
0:52:03 > 0:52:05I think another drumroll is worthy here.
0:52:05 > 0:52:07Another drumroll, come on.
0:52:09 > 0:52:12POP Yes!
0:52:12 > 0:52:13Come on, a bit of applause.
0:52:17 > 0:52:19What a great flame. That's fantastic.
0:52:26 > 0:52:29So as we've seen, in terms of using energy,
0:52:29 > 0:52:34producing meat isn't particularly efficient, so are there...
0:52:34 > 0:52:36alternatives?
0:52:36 > 0:52:41Interestingly, there is a source of protein just as energy-dense as beef,
0:52:41 > 0:52:43but it takes...
0:52:43 > 0:52:47less than half the amount of energy to produce, and luckily for you...
0:52:48 > 0:52:51we've got some with us in the lecture theatre today.
0:52:51 > 0:52:52And these are...
0:52:54 > 0:52:56..insects, crickets and mealworms.
0:52:58 > 0:52:59Would anybody like to try one?
0:52:59 > 0:53:02So let's have a look, the camera there, look.
0:53:03 > 0:53:04Look at that.
0:53:07 > 0:53:09AUDIENCE CHATTER LOUDLY
0:53:09 > 0:53:14They're perfectly safe to eat, so if you want to try them out, just...
0:53:14 > 0:53:17I think they're going to go round. I'm going to try one of the crickets.
0:53:17 > 0:53:20AUDIENCE GROAN Mm.
0:53:20 > 0:53:21They're great.
0:53:25 > 0:53:26No?
0:53:28 > 0:53:30Try them out. There's some over there.
0:53:39 > 0:53:40Who's tried some?
0:53:50 > 0:53:51They're nice.
0:54:04 > 0:54:07So what do you think? Have you tried them?
0:54:13 > 0:54:15OK?
0:54:15 > 0:54:17OK, I...
0:54:17 > 0:54:20OK, I've...
0:54:20 > 0:54:23I've tried them and I think they are, actually...
0:54:23 > 0:54:25I think, actually, they're quite tasty.
0:54:25 > 0:54:28So that stuff, that really is the fuel of the future,
0:54:28 > 0:54:33and it's time to get the results from our big energy experiment.
0:54:33 > 0:54:36MUSIC STARTS
0:54:40 > 0:54:41MUSIC STOPS OK.
0:54:41 > 0:54:45HUGH SNORES So we're going from the active group to the back,
0:54:45 > 0:54:47to The Lazy Lecturer.
0:54:47 > 0:54:49So, Hugh, how are you doing, Lazy Lecturer?
0:54:52 > 0:54:53I've done very well, thank you very much.
0:54:53 > 0:54:55I've had a lovely sleep this evening, thank you.
0:54:55 > 0:54:58Oh, good, I'm glad you had a nice comfortable time.
0:54:58 > 0:55:00Great, I'll come back to you in a second.
0:55:00 > 0:55:05Backstage, we've added up the numbers and the results are in.
0:55:05 > 0:55:08We've taken a sample of you lot and we've got the final figures,
0:55:08 > 0:55:09which have been fed to me.
0:55:11 > 0:55:16Did you know that in terms of AA batteries, The Couch Potatoes,
0:55:16 > 0:55:21the amount of energy used is 4,498.
0:55:22 > 0:55:24In terms of AA batteries
0:55:24 > 0:55:27for The Movers And Shakers, it's 4,942.
0:55:29 > 0:55:34So, really, the half of the lecture theatre that was moving about all
0:55:34 > 0:55:35that time, The Movers And Shakers,
0:55:35 > 0:55:40used just a bit more energy than the team who were just sitting,
0:55:40 > 0:55:42so, again, the overall difference...
0:55:43 > 0:55:46..is pretty small overall, for all of us.
0:55:47 > 0:55:51So let's go to our Lazy Lecturer once more, Hugh,
0:55:51 > 0:55:54who's been lying down doing nothing for the whole lecture.
0:55:54 > 0:55:57Well, actually, you've burned energy doing absolutely nothing.
0:55:59 > 0:56:01Life is expensive.
0:56:01 > 0:56:05So, even at rest, my heart would be working between one and two watts.
0:56:05 > 0:56:08When the explosions went off and I got a bit more excited,
0:56:08 > 0:56:11probably running up to four or five watts.
0:56:11 > 0:56:13Brain alert is running around 20 watts,
0:56:13 > 0:56:16but maybe a little less when I was sleeping.
0:56:16 > 0:56:18So there's constant activity going on,
0:56:18 > 0:56:22even the work of breathing will be consuming around 4-5% of your total
0:56:22 > 0:56:27oxygen consumption, so even sleeping takes quite a lot of energy.
0:56:27 > 0:56:30Well, thank you, Hugh, for snoring through my lectures.
0:56:30 > 0:56:33And thank you for coming along to my lecture today.
0:56:33 > 0:56:36- Thank you, Hugh.- Thank you for having me.- Shall we applaud him?
0:56:46 > 0:56:51So why didn't The Movers And Shakers use loads more energy than The Couch Potatoes?
0:56:51 > 0:56:56Well, just keeping our bodies warm and alive takes a surprising amount of energy.
0:56:56 > 0:57:00Keeping our heart pumping uses 5% of our daily energy.
0:57:00 > 0:57:03Our brains, 20%.
0:57:03 > 0:57:06Our liver, well over 20%.
0:57:06 > 0:57:12In fact, about 70% of our energy goes on simply keeping alive,
0:57:12 > 0:57:16so what's the total amount of energy we use over a whole day?
0:57:16 > 0:57:23If we scale up the results from the audience it comes to approximately 900 AA batteries.
0:57:23 > 0:57:28If we divide the amount of energy we use over a whole day by the number of seconds,
0:57:28 > 0:57:29we get a power rating.
0:57:30 > 0:57:37This figure tells us how much energy it takes for all human activity.
0:57:37 > 0:57:41Our movements, our thoughts, our dreams.
0:57:43 > 0:57:45The answer may surprise you.
0:57:45 > 0:57:46It surprised me.
0:57:46 > 0:57:50Each person has the same power rating as...
0:57:53 > 0:57:55..100 watts light bulb.
0:57:56 > 0:57:59That is clearly a light bulb moment.
0:58:01 > 0:58:03And, next time, in our 80th anniversary Christmas lectures,
0:58:03 > 0:58:08we're going to try and make a mobile phone last a whole year without
0:58:08 > 0:58:13plugging into the mains, and also break a world record.
0:58:13 > 0:58:15Thank you and goodnight.