The human body as an energy system - 2016 CHRISTMAS LECTURES with Saiful Islam 2/3

we're all more powerful than you might think the sound you can hear now is actually the sound of my own heartbeat and if you listen carefully you can hear all of yours joining in so you might think that this is just biology but on a fundamental level What's Happening Here is a transfer of energy every single one of us is a finely tuned energy conversion machine honed by millions of years of evolution so in this second Christmas lecture on our 80th birthday I'm going to investigate how humans other animals and machines use energy and whether we can supercharge ourselves to increase the performance of the human body so welcome to the 80th anniversary Ro Institution Christmas lectures we are all walking talking powerhouses I'm cul Islam I'm a professor of chemistry at the University of b like you my body is converting energy all the time so let me show you with this very sophisticated infrared camera so this camera unlike a normal one it actually looks at heat rather than light so give us a wave this bit of the audience come on so as you can imagine bright red means hot and the blues are cold so this side I'm going to get you give me a wave okay let me see if I can get you into Focus okay so quite a few and then over here let me get into Focus another wave okay so you're all as you can tell giving off heat and actually wait a minute there's either somebody seriously ill or uh a bit dead oh yeah just a mannequin okay um as I said we're all giving off heat so um earlier we took a temperature of this lecture theater and it was 18. 7 degre C and this is the reading right now so you can see that it's 20. 2 so within an hour it's gone up a bit so we are generating quite a bit of energy but just how much energy are we all using is the human body a gas guzzler or an energy saver I think it was great to hear our heartbeats just now every one of you is wearing a chess Monitor and I've got one too it's kind of strapped here feels a bit uh uncomfortable and so what we're going to do we're going to try and find out how much energy we all burn during this lecture so these are a couple of laptops and you can see it's got lots of little squares it's basically all the different energy monitors so if you look you can see just about the different numbers and the different data and if you look at the screen don't if you can see carefully but right in the top right hand corner where there's a little flame that's the calories burnt the bottom left where there's a little heart that's your heart rate and the central figure is basically just the energy consumption but there is a Twist to this live experiment um we want to split you up into two groups to do a bit of a large scale experiment so roughly from here the central group here to the right okay so it's going to be roughly here to the right you're going to be in the group what I'm going to call the movers and shakers and you're going to be moving up and around all the time when you hear this music come on let's get up come on up you get come on that's it come on

you can do better than that right now remember when you next hear that music I want you all to get up and do exactly the same thing Str your funky stuff okay right the other group you're going to do absolutely nothing uh um actually we've got a special scientific term for you guys this group is going to be called the couch potato group okay uh so we're going to see the difference because we've got the um the chest monitors we're going to see the difference between the groups towards the end of the lecture so as part of our 80th celebrations we've invited Christmas lecturers Past to help out so to help us with this demonstration it's a pleasure to introduce the 2007 lecturer Professor Hugh Montgomery he's out there hello Hugh thank you for joining us it's a pleasure thank you how does it feel to be back uh frankly terrifying but less than it was last time I okay well we've got Hugh to do something a bit special we're going to ask H to do as little as possible he's going to actually just basically lie down up there for the rest of the uh lecture and we've got a special term for him he's going to be called The Lazy lecturer so uh is that okay with you here absolutely fantastic more sleep hope made things comfortable for you it looks lovely I've got my coat so it's pillow so where does all this energy we're burning come from so as a scientist I love doing research and testing ideas and I didn't an experiment on myself so the experiment was that I would actually take a food diary we would look at all the food I'd eaten over a whole week and you can see it's pretty mixed and dodgy diet um so this is the food I've taken in for a whole week so I actually need a volunteer to help me well actually a couple of volunteers to help me scrape in so you want to come down yep and one more so in the purple t-shirt yes if you want to come down so can I take your name igy igy tally so we got Iggy and tally so you can see this is um some of the dodgy food I've eaten some of it better than others so we got a special task for you we're going to actually ask you to pass on the food to Iggy and he's going to put it that into that container there so what we've got some scales a container and just do it as fast as you can and if you just pass it on to Iggy and we just get that food into that container I scoop it in yeah just scoop it in so we're going to just going to measure it later just get it into that container yep so you can see actually I'm quite keen on musle there's quite a bit I don't know how I ate so much soup so we got there then okay and then I have too much bread okay come on just carry on doing it you do that come on okay right you just carry on doing that and if you can't reach over there's some stuff yes there's some stuff underneath there so while they're doing that so I like you to welcome to analyze the results last year's Christmas lecturer Dr Kevin Fong yes welcome back thank you how's it feel to be back in this uh theater you know I really wish I was giving the lectures this year you're welcome to take over yeah I was kidding you can do it um this is your uh week complete intake it see it is so uh we're getting them to pile it in there and I think they're nearly done so I'll yeah well done so I'm going to make that easier for you why don't you get it in there go on so um what do you think of diet honestly as a doctor this is not good cyel there there's a lot of Pizza in there I know chocolate it's only one piece do you want a bit no I I so you there's not exactly you're uh five a day

in there is laughing you're right it's the fruits content I don't know what happened that week I think I was stressed by these lectures actually yeah so we're nearly done well done you two well done we got one more this is it ah thank you should we thank them thank you very much right we're going to try and weigh the amount of food that's actually gone in and it's what's the reading there it says about 5. 5 kilos so that's Ry I've had over a weeks not too bad well yeah not too bad in terms of quantity poor in terms of quality yeah well as a scientist you'd appreciate this I like to do the proper science so not only did we look at the food going in we also so oh we also looked at the food going out so uh any volunteers want to scrape help me scrape this in any volunteers no surprises there yes they should be something I should do so uh let me do this look I know I was famous last year for drinking my own urine but this is really pushing it I mean really I'm going to use this spoon here so let me try and get it in there yes oh let's get it in cyel have you literally got me involved in a crap demo here yes oh no it's chocolate what do you think so should we take shall we take the reading okay so you got about 1 and A2 kilo 1. 6 kilo yeah and it was and you had just short of five kilos of food in there yeah about just over five so why the difference well so you've got about five let's say 5 kilos of food and about 1 and 1/2 kilo of out yes who there so what we've got sort of three and 1/2 kilos difference uh and honestly most of that food actually is water um and that's absorbed by your body but then the rest of it uh you use what's in the food the protein in particular to build your body to build the organs what to grow you but most of it is used in generating the energy that drives you and everything you do so there is some point in eating that terrible diet of yours okay well thanks for helping out on this particular slightly unusual demo thank you Kevin Fong yeah I won't shake your hand thank you okay have we again right thank you movers and shakers so exactly how much energy is in the food we eat burning food is a bit of a tradition at the Christmas lectures uh if you look at here there's Kevin again doing some burning there it's a good way to find out how much energy food contains so we're going to do something thing I've called the Great energy bake off so food has different components and for this I need a lamp coat and some glasses so it's got fat sugar and protein but I wanted to look at them separately so to help them burn we're going to soak them in liquid oxygen so just to let you know it's the food that's burning not the oxygen Okay we'll also see it I think we've got an infrared camera that's it over there it's going to monitor the Flames given off when I burn the separate food types so I've I'm really keen on this torch so and uh we've got some liquid oxygen so we're going to start off with some sugary substance and you can see this here so we've got merang on the left some protein powder in the middle and lastly for the fat some pork scratchings okay let's start off with the sugar the merang okay so off you go and I'll get this flame it's a lovely flame yes great so I had a bit of a flame so let's move over to the second one protein it's a protein powder

that was pretty good wasn't it yeah that was great so um and then lastly the pork scratching fat so this is our last one come on that deserves Applause come yeah yes so this is some replay of the infrared camera and you can see look at the temperature it's got to that fat went up to 556 de C pretty hot so um so you can tell which one W won the great energy bake off it was clearly the fat but we can usually measure I mean that's obviously a lovely display but we can measure energy from burning much more accurately than just using an infrared camera so let's look at the values you would get from the different food types and we got a special energy meter to display that but it's not any old energy meter it's an energy meter in units that hopefully you can all understand it's in double a batteries units are usually kilo calories and kilog so for merang what do we get so let's have a look merang about 25 AA batteries protein away we've got also 25 lastly I think you can guess what you'll see with fat so lastly fat what's the value for fat it's look at that 56 AA batteries so it's over double the other two we can tell this if you look at the number of kilo calories on the packaging of fatty foods they're a lot higher and that's because a kilo calorie is simply a measure of energy I mean have a look next time you go food shopping or look at the um the sweets and crisps that you eat so not all foods are this energy rich and not all animals have evolved to eat like us I'd like you to introduce you two very special guests they're strange and exotic creatures but please welcome them a bit quietly okay yes your gentle clap that's so nice Okay um this is Faith and this is Bonnie the goat and the handlers it's nice to meet you Alice and Tom thank you for coming in very I describe them as exotic perhaps they're not quite exotic but they are remarkable animals has to do with their digestive system allows them to eat food and access energy that we can't all of us they're called ruminants what would be nice is a volunteer to come down and feed them oh yeah why don't you come out to yes you want to come down do you want to a quiet Applause quiet right can I take your name Samuel okay Samuel you've got some uh I think we've got some spring greens very partial to it if you take a small handful you carry on feeling so um they eat spring greens and they also eat hay as you can see there so how do they break down that tough material they have a very special extra stomach where bacteria ferment their food this breaks down tough plant cells that we can't Digest oh very sweet uh they even bring up food from their stomach back into their mouths so they can actually chew it all over and over again um I'm not sure if any of you would like to do that um but hey has a lot less energy than pork scratchings Faith the Sheep has to eat three kilos of hay a day just to get enough energy to survive and in the fields she must graze for up to S hours a day that's a huge amount of time and hay so let's all thank all of them but a bit our quiet claps okay let's quietly thank you Al let thank you Tom okay thank you very much okay so if our diet was just hay that there we'd need to eat 4 and 1/2 kilos a day and time would take forever can you

imagine munching through all that oh no that's okay so the high energy density of our food is one of the key factors in how humans have time to do all the things we're really good at we've done the sums and I'll show you the results on our energy meter when I jump over those uh so for example if we want to play the piano for an hour it's going to be 91 AA batteries that's in an hour if standing up and painting takes 152 AA batteries just walking in an hour takes let's have a look at walking 120 27 AA batteries so where does all the energy in the food that I ate earlier on where does it all come from there's a fundamental principle of energy you can't create it or destroy it can only be converted from one form to another so the food itself must have got its energy from somewhere so let's follow the chain of energy and find out and to show you I've got another exotic creature salmon it's a bit of a violent salmon so what this salmon it wasn't part of my weekly diet where does the salmon get its energy from for this I need three volunteers maybe somebody from the side yourself there and one in green and one final one yes one in the blue t-shirt yeah come on down so hello there can I tell your name Lizzy Isaac and what's your name Amar okay I'm going to put you in sight of height order so if you go that side you go on that side let's and if you come across there so get in a straight line okay want nice clear picture of you so I'm going to get you to hold the lovely salmon okay all right so this is a bit of a food chain so we want to see really where these different creatures get their food from so I would like you to reach in there so what does the salmon eat salmon eats put your hand in the mouth and pull out what the salmon eats it eats basically smaller fish and in this case it's just a mackerel but what does mackerel get its energy from its food so why don't you stick your hand in and see what you can pull out yes that is phytoplankton okay a good representation of phytoplankton so phytop is just very tiny Marine plants but like all plants well they get their energy from the Sun so you can follow the same chain of energy for almost any food type and any food you choose but it always ends up at the Sun so every single bite of food we take is effectively solar powered great well thank you all three of you thank you for coming on so let's thank them again right but it's not just our food source that is important it's our size as well so um let me get this out so here we have a mouse um sadly it's a x Mouse uh well these are the xmouse lectures uh oh so um unfortunately we wanted to use a real Mouse but uh we were a bit scared that it might actually die shock seeing you lot um but it's the reason I wanted to bring out this mouse is that it eats about a third of its own body weight every single day just to stay alive if we humans ate a third of our body weight a day what would it look like it would mean eating about 150 cheeseburgers a day if we were equivalent to that Mouse the difference is that really small animals like this wee Mouse um has to eat a lot more than large mammals per unit weight and that's because the Mouse has a relatively large surface area compared to the volume of their body so this means they lose a lot

more energy as heat so in this case size does matter okay you're doing really well there so earlier we saw that burning food releases its energy but we obviously don't actually burn food inside our bodies so how do we turn something like that salmon into energy that we can use so I'm a chemist and thankfully a lot of this is chemistry so up on the screen is something I'd never thought I'd see this is a view of my own I stress my own lower intestine from the inside um to get this image I had to swallow a very clever device a very special device uh this isn't the actual one but it looks a bit like this if you have a look that is what is called a capsule endoscope and essentially it takes photos of my inside in real time as it was going through the body so I had to starve myself for 2 days to get a clear image so let's go back to the beginning of the footage and let me talk you through what happens you can see I'm these are my fingers I'm holding the capsule and I'm actually there's my teeth you can see it just past my tongue and off it goes down that Clear Channel and it's got straight actually the guy who was operating at the local hospital said it went down really quickly I really had starve myself so it went down into the lower intestine and there it is usually you see lots of kind of food along the way so what is happening within my mouth and in the stomach well it's basically some chemistry there's some enzymes that break down complex molecules and they break them down into sugar called glucose and in my lower intestine that glucose goes across the intestine walls straight into my blood so the blood carries the glucose into muscles and organs where it reacts again giving reacts again to give them energy um I should say we stopped the image there I didn't want you to see uh the lights at the end of the tunnel so to speak yes off you go yes keeping them fit that's it I'm going to join in this time pretty good okay so um we've just had some really active people so I think it's time to catch in on Hugh how are you doing right so what does this mean for our performance can we supercharge ourselves using sugar the answer is uh sort of sugar gives you that quick burst of energy that Sugar Buzz that can be useful if you're doing a lot of exercise um I'm I mean there's a reason obviously that you don't see Annie Murray kind of snacking on pork scratchings between games but sugar as you probably know has its downsides too those spikes or that rise in sugar levels in the blood aren't good for you long term and if you take in a lot of sugar it could end up being stored and so how does the body store some excess energy well we got a bit of a favor from a local clinic and they kindly allowed me to borrow some real human fat that is real it weighs about a kilo it looks a bit ready because of the blood in there but how much energy is in that kilo of human fat so let's go over to the energy meter to give you an indication so that kilo goes up to yes a massive amount that kilo has 1,869 doublea batteries of energy that's a lot you know much greater than the stuff I showed you before it would power me for three to four days so this reminds us that humans are energy storage machines as well as energy conversion machines so someone like me might be surprised to know although you

saw my diet earlier I have about 10 times this Beaker of fat on my body it means that if I was on one of those survival programs um I would survive up to several weeks without eating but long term we obviously need to strike a balance between the amount of energy we take in and use up otherwise the excess leads to getting us overweight so does our body generate any other forms of energy from our food we've talked about heat um we've talked about movement but there is something else the human body is far more electric than you might think to show this I need a volunteer to help me play a little game yes if you could come down in green yes can I take your name Isabella this is Isabella and elizabth why elizabella is getting hooked up I'll explain what's going on this kind of equipment here allows someone like Isabella to control someone else's actions using the power of electricity uh and she's going to get wired up um on the other end um I haven't asked another volunteer because it can be a bit weird and feel a bit uncomfortable but it's a great pleasure to introduce and invite the 2013 Christmas lecturer to help out Professor Allison Ward H there Alison great to see you thank you Allison for joining us and helping out what's the feel like being back here in the lecture theater again it feels great to be back but not in the driving seat okay so what we're going to do we've got a cup of water okay um so and why don't you just take a sip now right okay because uh we're going to show no tricks yet that's fine that's all to clear so Al if you want to show us what they've done to you outside yeah they've put these stickers on me yeah okay and they're all fine nothing painful no so what James is going to do he's going to hook you up and we're not going to get started yet so what's basically now we're connecting Isabella to Allison so we're going to maybe do a bit of a test at the moment it's not on I don't think it's on so let's why don't you try and clench your fist and see if it affects her nope nothing's going on so the point is that when I switch this on Isabella in principle and hopefully in practice can actually stop Allison having another cup of water so if you pick that up okay let's have a bit of a drum roll okay off you go try and drink the water go re it yeah oh my goodness three move it right you can stop now I'm going to turn it down so uh Alison looks like you've got You' got a bit of a drink drinking problem I certainly have yeah right so how did that feel well it felt very weird so I felt sort of Sparks here like a bit of an electric shock and then my fingers just went completely mad I had no control over them at all was it painful no not really just weird I haven't tried this yet so I don't know what it feels like but I want to try it later weird yeah I'm not usually so easy to control so um Alon I know you're a biologist and we have discussed this so tell me what is actually happening what's happening between Isabella and you well our neurons have evolved this remarkable ability to conduct electricity so when a neuron or a nerve is activated like we're doing here artificially it causes a different in the voltage across the membrane and so really our neurons are tiny little batteries and this difference in voltage triggers a wave of electricity that travels all the way down the neurons until it encounters muscle and it causes the muscle cells to contract like the ones in my fist and that stimulates the movement so do they know how fast that signal travels well up to about 250 M an hour so about the speed of a Formula 1 car so it's pretty fast very fast so that's why that transfer was so Speedy exactly yes obviously that was a fun demo but there are more kind of serious applications of this type of Technology amputees people have lost their limbs can actually control their prosthetic limbs using the power of electricity a bit like this so um so we're going to do one more demo just for we don't need a drum roll this time so don't do it yet and Alison I know I'm sorry about this I know we're going to make you do it again so thanks for being such a sport so okay going to Isabella we're is trying to stop Allison drinking again come on you

do it oh no all over Ni no oh no I'll turn it down right I think we should give Allison a hand okay so how much electricity do we generate a single nerve firing produces a very small amount of electricity we have well over 80 billion nerves in our brains alone that's eight with 10 zeros after it this adds up to enough electricity to charge a smartphone in about 70 hours so of course uh we won't be plugging phones into our brains anytime soon so we can use technology to generate electricity from our bodies but what about our bodies themselves how good are they at converting and generating energy how powerful are we and how do we compare to something like a machine there's only one way to find out let's pit them against each other let's have a fight okay so we need a professional for this so please welcome Britain's human powerered land speed record holder Ken Buckley hi there so Ken um You've Got This Record tell us more about this record what does that record mean so it's the British land speed record for human powerered vehicles so basically as fast as you can get a human powerered bicycle to go okay so how fast did you get so we did a top speed of 76. 6 milph so tell me about the training you need to get that to that kind of speed what kind of training do you need to do so I do about 15 to 20 hours a week of uh mostly on the bike some in the gym and a lot of stretching and yoga and other stuff as well okay so what we've got here we've got your bike and we've hooked it up to an electrical generator with a difference we've got to connect it up to some devices so we' got some lights we've got a blender and we've got a kettle here and we're going to see if the human machine can help to power some real machines okay so we're going to get a top athlete so um I think we need a bit of a drum roll for this don't we so let's have a little drum roll and off you go so you can see the lights coming on so that straightforward so lights don't need that much energy so let's see if we've got the blender no problem for the kettle it's very difficult to monitor the kettle so we've got an infrared camera okay so we got the kettle coming on and that's the tough one so this is the temperature of the kettle 21. 6 de so it's cold water or warm water so let's see if it goes up no can you get to 100° okay thanks okay let's stop there let's give an Applause so as you can see it was easy to get to the lights and the blender but that boiling a kettle needed a lot of energy and uh I think you're hotter than the kettle right yeah actually let's put the thermal camera on Ken let's see how it's looking look at let's compare it to me and I haven't me do anything that look like tough work yeah that was hard yes okay thank you very much at the absolute Peak a highly trained professional can't even boil a kettle so compared to some common machines we're not very powerful so can we improve our performance for the same amount of energy can we supercharge ourselves to find out i' like you to welcome the 2010 Christmas lecturer Professor mark movik great okay Mark you come down here so um Mark what's it like to be back in the lecture theater I can honestly say I would not rather be anywhere else absolutely I don't blame you and if you just watched our cycling generator how do you think you'd Fair do you exercise much uh it's mostly brain power I have to admit uh yeah I sit you sit I sit any sports at all I cycle to work cycle to

work I was looking that cycling there I was thinking yeah I could do that all right well uh what if we use these running machines to pick you against Ken our uh cycling land speed record holder let's bring him on Ken are you there hi there Ken again hello this is Mark hi Mark again so um we're going to do an experiment we just want to see how much energy you're going to use so we're going to start getting you kitted out so if you could both get onto the treadmills what we have here is obviously a couple of treadmills but they're connected up to some monitors and they're going to be putting on some masks these masks connect to a Vox machine what it does is it measures and I'll you can see on the screens there it measures the amount of oxygen that you take in and is given out and why that's useful is that you can actually relate it directly to the amount of energ energy used the energy expenditure that's the two e you see on those two monitors and we're just going to compare the two so um before they get going a simple question who do you who thinks that Mark will be using more energy than Ken hands up okay so who thinks that Ken will be using the more energy oh interesting right so let's get the treadmill started okay off they go okay so let's see how they're doing there is a difference already between the two quite a significant difference so let's let it run for a bit see uh See if we can tire out Mark just from walking I I'm actually embarrassingly if I knew you could do this to me I wouldn't have worn a three-piece suit you know okay so let's begin to wind down should we stop now okay let's stop them both so you can see if you look at the numbers Ken is actually using more energy than Mark which is interesting um I have to say Ken has more muscle than you Mark and that the main reason Ken being more muscular needs a he needs more energy to move that's because his body has adapted to both consuming and generating more energy as with everything to do with energy you don't get a free lunch so this here ooh nearly came off this is when Ken is training this is his daily diet so Ken being an athlete is definitely supercharged Ken can do more work than most of us so let's thank Mark and Ken for doing this uh demonstration thank you Mark thank you thanks for coming on yes well done some good moves there actually so let's catch in on Hugh how you doing Hugh he looks very comfortable we'll come back to him so there are ways to supercharge our bodies and improve our performance it's called training what about increasing performance without training is that possible there's a drug that many athletes take to increase their performance it gives them better reaction times and helps them with their fatigue it used to be banned but use was so widespread it's now become legal and I'm going to take some right now live on this stage tonight the drug is caffeine actually you need some that's nice and hot um so I was thinking about how to show you the effects of caffeine on reaction times so please welcome our warm up man Matt good to see you so matx I understand we got you to do something uh that was a bit difficult we asked you to uh give up caffeine yes for how long well even though I do love my coffee somehow you convinced me to go for 2 weeks completely decaffeinated so no coffee no chocolate no tea it's been a nightmare so you're completely decaffeinated I am absolutely deated my goodness with that decaffeinated State what do we do to we

we thought we'd test your reaction times yes so uh you can tell us more about this is a batac machine I believe so what do we get you to do this tests your reaction Times by lighting up these different letters and uh numbers and you've got to hit the one that's lit up as fast as you can and then that repeats as some form of unusual psychological torture for about 30 seconds so uh I think we might have some footage do we have some footage of you doing something earlier yes so uh talk us through it so there you are so there I am this is me without caffeine at all for 2 weeks and I'm doing my can't even find it there it is I'm doing my best to hit the lights as fast as I can and I'm doing poorly I think we've given you some coffee since then have we giv you some coffee yes so since that was recorded I was allowed coffee for the first time in two weeks I've had three coffees since that happened and my brain suddenly feels alive again so what was the results from that uh 29 buzzers hit in 30 seconds 29 so fewer than one a second and that's me enjoying my coffee uh as when we're getting ready for the recording I love it really enjoying it yeah I know really enjoying it so could be so we're going to actually test Matt again after that after he's had the coffee so um why don't you get into position but don't start yet we're get into position I think you know how to start it off do you yeah I hit e and then all it all breaks off yeah go so I think this really does deserve a super duper drum roll for everybody so come on and go time out yes I have to congratulate so what a what an improvement so that Catherine really had an effect there I feel alive you feel alive so how did it feel that time amazing like everything narrowed in and I was just seeing the machine seeing the lights and I was almost moving before I was thinking okay well let's thank Matt once more thank you thanks a lot obviously that was just a demonstration it was a sample of one um but there are proper sign scientific studies with larger sample sizes have shown that caffeine does have a very strong effect on performance it increases activity in the brain and tricks the body into releasing adrenaline it can improve your reaction Times by up to 10% and even reduces your feeling of fatigue but caffeine is no wonder drug the increase in performance is Tiny but those tiny margins can make a big difference for professional athletes um but you're not obviously it's not going to make me Mo Farah so far we've looked mostly at improving the way our bodies use energy but can we look at Food itself earlier we worked out how much energy was in each food type but that didn't include how much energy it took to produce that food in the first place so can we produce food more efficiently so here's another cheeseburger here we can do the calculations did you know that each Burger takes the equivalent of 10 Burgers worth of energy to produce so all this to produce that that's a lot so why is it so much well wheat to produce bread needs irrigation and takes electricity but it's the meat that takes the most energy to produce so um better take this away before our next beautiful guests come on so this is definitely a very quiet welcome in fact probably doesn't need any Applause

so um this this is Inky minks here on your left and her babies with her and she's called jet and the handlers thank you very much Felicity and thanks for coming along oh aren't they lovely um obviously to get to this size iny would have had to eaten about 2,25 kilos of grain we got the real stuff now so in general actually I think Inky has to close her ears do she in general to produce just one kilo of beef take 7 kilos of grain and growing grain requires fertilizer irrigation and transport so in Pure Energy terms this isn't a very good trade I have to thank the handlers and Inky minks and their beautiful little calf to come in so uh thank you very much for coming in thank you cows also produce something else from their food let's see that with a simple demonstration so this is a bag or a balloon that contains the same amount of methane gas that Inky produces every single minute actually about the time she was in the lecture theater so did you know most of this comes from burps or up windies as my children call them this balloon Moon contains a lot of energy that normally goes into the atmosphere uh shall we take it away or set it a light set it thank you I've got a pyot technic expert to do this for us um I think we another drum roll is worthy here so another drum roll come on yes come on big Applause for a Great Frame that's fantastic so as we've seen in terms of using energy producing meat isn't particularly efficient so are there Alternatives interestingly there's a source of protein just as energy dense as beef but it takes less than half the amount of energy to produce and luckily for you we've got some with us in the lecture theater today and these are insects crickets and meal worms uh would anybody like to try one so let's have a look so if the camera there look at that they're perfectly safe to eat so um if you want to try them out just I think they're going to go around I'm going to try one of the crickets they're great no try them out there's some over there so's tried some very nice so what do you think have you tried them okay okay I've tried them and I think they're actually I think actually they're quite tasty so that stuff that really is the fuel of the future and it's time to get the results from our big energy experiment okay so we're go from the active group to the back to the lazy lecturer so Hugh how you doing Lazy

lecturer I've done very well thank you very much I've had a lovely sleep this evening thank you oh good I'm glad you had a nice comfortable time great I'll come back to you in a second backstage we've added up the numbers and the results are in we've taken a sample of you lot and we've got the final figures which has been fed to me did you know that in terms of ablea batteries the couch potatoes the amount of energy used is 4,498 in terms of AA batteries for the movers and shakers is 4,942 so really the half of the lecture theater that was moving about all that time the movers and shakers used just a bit more energy than the team who were just sitting so again the overall difference is pretty small overall for all of us so let's go to our lazy lecturer once more Hugh who's been lying down doing nothing for the whole lecture well actually you've burnt energy doing absolutely nothing well yeah I mean life is expensive um so even at rest there my heart would be working at between 1 and two Watts um when the explosions went off and I got a bit more excited probably running up to four or five Watts um brain alert is running around 20 watts but maybe a little less when I was sleeping um so this constant activity going on even the work of breathing will be consuming around four to 5% of your total oxygen consumption so even sleeping takes quite a lot of energy well thank you Hugh for snoring through my lectures and thank you for coming along to my lecture today thank you Hugh thank you for having me sh applaud him so why did the movers and shakers use loads more energy than the couch potatoes well just keeping our bodies warm and Alive takes a surprising amount of energy keeping our heart pumping uses 5% of our daily energy our brains 20% our liver well over 20% in fact about 70% of our energy goes on simply keeping alive so what's the total amount of energy we use over a whole day if we scale up the results from the audience it comes to approximately 900 AA batteries if we divide the amount of energy we use over a whole day by the number of seconds we get a power rating this figure tells us how much energy it takes for all human activity our movements our thoughts our dreams the answer may surprise you it surprised me each person has the same power rating as 100 watt light bulb that is clearly a light bulb moment and next time in our 80th anniversary Christmas lectures we're going to try and make a mobile phone last a whole year without plugging into the mains and also break a world record thank you and good night