Delightful and Dangerous Liquids - with Mark Miodownik

[Music] thank you very much for coming and for you know being here on a Friday evening I'm promised you an entertaining evening all about as Nicholas said the kind of weird stuff that's not solid but liquid and I'm going to talk a bit about candles I'm going to talk a bit about lamps I'm going to talk a bit about wine I'm gonna talk a lot about kerosene and it's all a bit about at the end a bit about liquid soap it was a pet peeve of mine and then at the end of that we'll I'll finish with what I want to say to you and then we'll open it to questions and you can ask me all these difficult things or frustrating things or wonderful things about liquids but they are amazing things only liquids we rely on them and they we delight in them a cup of tea you know kind of can you imagine your life without that or coffee if you're a coffee drinker but or a glass of wine perhaps but certainly water without water you really couldn't survive and we know that that's why for many days at all without water but of course but water isn't just good for us it also is a big killer actually one of the biggest killers worldwide is water and if you ever find yourself in the ocean for some reason with no with no land in sight you've got very little chance it will swallow you up but even if you're not you know somehow in the middle of the ocean somewhere even you're on land tsunamis floods rivers they'll get you so so with all these liquids and that was the point of the of the book there's a kind of sort of Jekyll & Hyde character two liquids they're both wonderful and you know we need them and we love them but they also almost always have a darker side and that's what I want to talk about for an hour now with you I'm gonna give you a few examples of them and now you might ask why did I start to talk this way about liquids and of course we've all been you well not all presumably not everyone but lots of us have been to airports and you know since sort of 2009 they've been frisking us for our liquids and we're not been allowed to take liquids on except for a hundred mil limit and I want to talk about that limit what what is so magic about that limit that makes liquids okay and I'm sure that will come up in questions as well but I was always I was really amazed when I talked to my colleagues I was like you know come on surely we've got kit that can tell you whether you got a liquid explosive or or a liquid spread surely it can tell the difference but it turns out that actually when it comes to liquids they are inscrutable and so these these security rules that came in came in because essentially it is very very difficult to tell the dangerous ones from the safe ones but then once you're on the plane right there's another sort of liquid themed thing that goes on right I mean I skipped the point where they sell you your liquids back after you go through security isn't they you walk through security they take them all off you then they go would you like some perfume would you like some booze would you like some coffee anyway but but then you get on the plane and and and you're sitting down and you're about to take off and you get the you know the preflight safety briefing and someone stands up and says you may think that you're safe [Music] but don't forget that we might land in water another big body of liquid and then you will drown but never fear because under your seat is one of these and if you put this on you'll be fine because there's a whistle I always like the way they think they pretend to blow it as well ah don't worry the plane is crashed I am floating in the darkness but I've got a whistle it's gonna be fine and then not to want to alarm you too much they then say you know when we're flying at 40,000 feet and there's not much oxygen up there there might be a loss of cabin pressure now that's a funny term is it what they mean by that they mean there's a crack in the fuselage but they don't want to say that because that will alarm you but if there is a crack in the fuselage all of the air will be sucked out of the cabin and you will be gasping for breath because at 40,000 feet there's not enough oxygen to remain conscious but never fear these will come down from above and save you and make sure to put one on before helping anyone else now you're thinking whoa how likely is that but they continue on with this safety briefing and they get this out and it's at this point you start to think this safety briefing is not is it really about safety because this seatbelt which they elaborately demonstrate in front of you this is how it works all the way and you release it like this is wouldn't it be legal in a car going 30 miles an hour you're going 500 miles an hour how does that work why is that reassuring at all and of course the reason is that when you had that loss of cabin pressure if you didn't have one of these on you would also be sucked out it's really just to restrain you in the event of loss of cabin pressure it's not anything to do with a crash we won't talk about the chance of survival in the crash and they don't either they're not good but the thing is the strategy of engineers and it's been a good one let's face it has been just to make sure they don't crash and they are incredibly reliable I want to reassure anyone here who is afraid of flying and those who are not that is state it is statistically without doubt the same for this form of long distance travel by a long long long runway so you're very very unlikely to come a cropper so why if it's so safe and it really is incredibly safe why do they go to all this elaborate business of alarming you about the safety it's not almost questioning it and I was thinking about this one day and I realized suddenly occurred to me what this is all about it's not about any of those scenarios at all they're distracting you right there's something else they're not telling you they don't want you to think about it because if you thought about it you might want to get off the plane and what it is is that underneath your seat is a hundred thousands litres of kerosene and kerosene has ten times the energy density of nitroglycerine the very stuff they frisk you for to get on in which they will only allow you 100 millilitres and there is a hundred thousand litres under your seat this is alarming if if airplanes were more like this lighter here which we'll get to later but and they were transparent so when you got on them you could see the liquid and then the compartment above where you sit I don't think many people would fly I just think even though it's safe you just look at that stuff and you'd go woah wow we're essentially on a rocket strapped to it and they've made this safe somehow anyway they have which is amazing and so I think we'll get back to the preflight safety what I believe it really is one of the things I think it is a distraction stop talking about that and this story of today's talk is going to be about how we got to this point how we got to this a-mei using liquid kerosene area aviation fuel where we got it from why we've managed to control it so that actually you know plane journeys are that safe but also what what else it means for us I'm gonna start this talk with a candle to talk about this and it's very appropriate in this space about more than one candle because obviously this is the wrong institution and the famous lecturers here were first Humphrey Davy who we'll get to in a minute and then his apprentice Michael Faraday who did a series of public lectures when you know this was the place in the world that was the crucible of how to communicate science the public and get the science involved in public this very place we're in now so it's a very very you know incredible moment and you know Michael Faraday chooses to give a whole series of lectures 5 lectures and I've got a replica of his notes here of those lectures on the chemical history of the candle as he says and he says there's no greater phenomenon I would read it verbatim I thought I was gonna be able to but I can't read his writing it's really difficult but I have my own copy in the lab and it's typed I wish I'd brought it but anyway he basically says you may be surprised that I'm going to talk about a candle for an hour I'm not by the way but he did but I can tell you that there is no law in the universe that is not somehow germane to how this thing works that we cannot extract some knowledge from and it was it's just a fantastic series of lectures if you get the chance to read the book I really really recommend it so I'm just going to touch on how he starts those lectures because I was going to get us into liquids and kerosene and liquid fuel so the first thing I say is that you know you see a candle and you think whoa I mean that's that's kind of a pretty simple thing how hard can it be it's not that complicated and obviously it's some fuel isn't it it's a solid fuel in the form of wax and you're burning it and that's creating a flame but it's more complicated than that it's it's a very very it's a very sophisticated piece of technology in fact but we're just so used to it that we perhaps take it for granted I'm gonna show you one thing about it that I find fascinating sup down and turn it out so now we've got the candle the other way up this is the same fuel you've seen it burning there's no difference top to bottom I try and get this to go though no chance right and you sort of know this right I can't get this to light I'm putting this hot flame onto it and I can't get it to light so what's the problem it's fuel it should burn why isn't it burning stupid candle okay so it's got something to do the wick so what's the wick doing well in order to get this candles to burn I've got I'm starting with a solid fuel which is these long carbon molecules like that wax is and I've got to get those carbon molecules to become a vapor and interact with oxygen so I've got to get that this to kind of become a gas now it turns out it's become a gas it's got to become a liquid first and I formed the liquid on top of that but then the liquid found it very hard to turn into a gas and mix with oxygen because there's just it's very hard for the oxygen to get into the surface but what if I can get the liquid to go up a very small wick and then evaporate then I've got oxygen coming in from all sides so I'm mixing it well so the combustion is good so that's what really happens when you when you light a candle wick liquid is being sucked up from the candle it goes up to the top of the wick then becomes a gas and then because I've ignited the first bit there's a self-perpetuating ignition that goes on oxygens coming in is being burnt hot air goes up that sucks more oxygen in that gets burnt it goes what and you think well where's where's where's this pump that's pumping the liquid up well yeah that's interesting isn't it how is it that liquids going up because things usually go down that's gravity right you drop things and liquids are usually no different from that if I pour some liquid it doesn't go up it goes down so why is this liquid to go up and if you don't believe it is actually going up and that is possible let me see if I can get this I'm gonna go to my camera here okay here's a that's there right uh-huh right you can see that right now if I this is a bit of a niche demo by the way just warning you if he doesn't go away well I got to get one in the middle in the front where's the one in front it's okay so if I if I if I if I now get sorry let me get my distance back right what I'm gonna do is is extinguished scandal and now I'm gonna light above it above the wick and basically if liquids going up the wick and then evaporating into a gas then it should it should likely guess without touching the wick so there we go and then always whoo that's right I didn't do that very well didn't see that I told you sorry okay do it again okay extinguish it light it I didn't work at all okay sorry but basically what's happening is is liquid is going up the wick its then evaporating and and then it's that it's that mixture of evaporated wax that's mixing with the oxygen so when you when you when you stub out a candle and you get that smell that's that kind of smell of a candle being put out what you're smelling is the wax the vapor of the wax and that that so that vapor is what you don't smell it when the candle is burning because you burn it and it's turning into carbon dioxide and water so where is this liquid you ask well there it is so that little cup there holds the liquid and that cup is a piece of architecture that the candle itself creates you don't make the cup it makes it itself by but by having it cool on the outside and hot on the inside so a little pool of liquid forms in there that liquid goes up up the up the wick that evaporates and you get this sell for pudding so this is a piece of technology that's incredibly sophisticated and really interesting but again we're back to this thing why why does the lick why is the liquid allowed to go up a candle what's that's going on there and that's this thing called capillary action and you kind of know it people talked about capillary action I've got a little vial here of ink which I'm going to get the focus on properly this time ah there we go and you know you know this but I'm just gonna put alright this is from the from the loos downstairs just not any sort of magic tissue it's just normal tissue handheld and they call it if I put that in there immediately the liquid goes up in is that the same way as the liquid wax is going up there we're not burning it this time but up it goes now that's capillary action you know this in fact when you go to the loo and you wash your hands and then you dry them with this the same things happening why should the water prefer the tissue to you it's because there's some tiny fibers in here and each fiber has like they're pressed against each other they have a little channel between them and the surface tension of the liquid likes the fibers more than it likes your hand and so it jumps there's a there's an energy difference that it likes to go to the fibers not your hand it jumps over to the towel and this becomes wet and your hand becomes dry and it's the same jumping that's happening in this clip no reaction here this is my towels work that's why you can have showers and baths and get out of them and then you can and you probably know that some towels are better it could be the reaction than others right some are kind of bit scratchy and they and you you rub yourself and you don't get so dry and others are very good at it and that's because of the fineness of the fibers and there are these things called so-called micro fibers and if you ever try and get sold a microfiber cloth to clean your windows by it because microfibers are a much finer form of fiber so they have a much higher capillary action and so you can dry your windows much better and yourself much better so once you know that surface tension exists and it affects things in fact it's the reason why there is a meniscus on this is why the liquid is trying to crawl up this wall of this jar a bit is because it likes the surface tension is wetting the jar and it likes it likes to do that so it's trying to pull itself up just like the wick is trying to pull itself up but once you can do that you can do some other stuff can we go to the visualizer I just want to show how there we go I've got a little a little little bath of liquid here this imagine this is you having a bath but a little you tiny little you here you are you're your app in a steel pin yeah but this is a strange bath because oh okay surface tension you are so fickle it's that easy it does depend on the on the surface of liquid sorry about this it's just so finely balanced all right I'm putting a bit of oil on there now from my hands I should just that should just tip us over I tell you what's happened is I've left that water out and it's changed the surface energy of it because you need a few impurities this is my theory okay science and action if in doubt replace the water so funny I played this you want me to stop now usually I wouldn't I want to show you something else there we go okay thank you very much [Music] now that's um it's floating on this liquid you can see it floating around that's why I've got the the in text below it because you can see it there now what's making that float is that there's a surface tension between the steel and the water and it's repelling the water and that repelling force just equals its weight but it's very closely pop finally balance as you can tell so if you make that any heavier you're you it's gonna sink so so with so with gravity and surface tension there's always this ratio so that's why very tiny things thin thin little fibers they can pull water up a long way and this is obviously how plants do it but but fat things and heavy things they get they get pulled down now the other thing is as I just was hinting at is that you can also change the chemistry of the of the surface and you can make things less or more the surface tension you can change it so I'm putting a bit of detergent in here and what happens is that it it sinks to the bottom so the chemistry of the surface and the and and the and the chemistry of the solid surface they interact with each other and the weight and what this means is that you can I go back to this is that it means that you if you're an insect you can float on water or you can walk on water oh it can we go back to the presentation oh yeah so this is a so this is this is an insect using this exact effect to be able to it's a so-called pond skater and and yet it's basically kind of manipulating the hydrophobicity so how much the water hates its legs to allow it to walk on top but plants do the same thing so plants modulate the kind of oiliness of their surface but they also do something else they increase the surface area by having little fib roulette kind of increase it they make they this is also called super hydrophobicity so they make water not wet it so when it rains and it rains on your car and the and the droplets dry you're used to knowing that actually there's a bit of grit and you get this patina on your car or anything all your windows of your of your house and you have to clean them but but plants don't suffer from that because what they do is they repel the water there's a whole load of people trying to borrow this technique to make self-cleaning windows and self-cleaning planes and so on so you can manipulate surface tension nature does it and we we've done it too with the candle so what next then we know that surface tension is important we know that wick is important we know how to turn a solid wax into light now if you go back in time our ancestors mostly lived at night in the darkness and when they did start inventing ways to light their houses it was the form of a candle if they lived in the northern hemisphere and and the fuel was often not waxed because that was quite expensive but tallow so leftover fat essentially from from killing meat and there was a big industry and in and and and you know cities like London would have tallow factories all over them if you were in the Middle East the fuel wasn't that the fuel was olive oil they had huge plantations of olive oil so they had a liquid fuel so instead of making a candle out of a solid fuel they made these oil lamps and they're all pretty much the same kind of design but there is this wick that comes out the top you can see and there's that the container and when you look back in time in the archaeological record you find all this all over the place so there's still manipulating surface tension they're still using tempered engine to pull a liquid up but now they're not using the heat to make the liquid it's already a liquid now this has some problems but it is for an average household they could probably only afford one of these lamps so people didn't you know it was it's a real luxury and even if you go forward in time - in this country - this a 17 - 18th century you could get a job and part of the perk of the job would be the number of candles you could have per night so otherwise you're in darkness so oil lamps or candles these were vital to anyone wanting to kind of step off the dark and do anything at all but in the Middle East that was sort of a special association with this because there was a myth that was at something called a jinn right which was a spirit of the oil lamp which would which would glow with a smokeless flame now what does that mean a smokeless flame well candles actually you're not so good for indoor pollution if they were invented today they wouldn't it would never be but if you put paper over them after a while what you do is you end up collecting a black soot that comes off them or it burst into flame that's one of those two things and that's more of a burn but anyway we get the idea but in the Middle East there was this idea that you could have a liquid that would give you a smokeless flame a spirit and that was the genie of the lamp and so perfection was a smokeless flame and of course this genie you know it comes up in many forms in folklore and this is Aladdin and the magic lamp and the idea that if you rub the magic lamp the genie is going to come out of the lamp so there's a lot of storytelling around this at the same time we get this chemist you know called al-razi or Razzies who starts to look into different forms of fuel - to fuel these oil lamps as I said before they're using olive oil and he finds these blobs of liquid tar that occur outside Baghdad and in fact they're using them actually to coat some of the roads it's a bit like the same stuff that we have coating our roads the asphalt of the roads and he he takes some of that liquid and and what he does he puts it in a line bit like this so it's an early form of distillation which he invents and he heats it up and and basically this this black liquid vapor comes off it and he collects that vapor and then the first lip the first paper that comes off he collects is his colorless and he starts to investigate it and burn it and lo and behold it burns with a smokeless flame and he didn't know it at the time but he had discovered aviation fuel there were no planes there were magic carpets but he had this liquid and it was it was an amazing liquid but it was it was made in the lab and he didn't really know how to understand what it really was and he didn't did lots of other different experiments but it never became a replication and never became an alternative to olive oil and there's lots of reasons for that one of which is that you know they weren't they weren't drilling for this stuff they were taking it out of the surface and so perhaps there was a limited amount of it underneath their feet of course we know now today that crude oil reserves in the Middle East in particular are very very high and this is just a map in 2013 of where the Isle the country oil production by countries are and there's a lot of this stuff it's a so-called fossil fuel and an oil is this kind of residue of old organisms that have been you know that died in such huge numbers under such conditions that they didn't decompose but in the second in the same way they do in an aerobic system but somehow got compressed and made into this liquid fuel and also into coal and other things but at the time even though there was a shortage of olive oil and it was a very valuable commodity and this perhaps would have solved a lot of their problems in terms of indoor lighting it wasn't an a viable option instead as I said they planted olive oil and they planted olive trees and in fact they paid taxes Voyles so olive oil was not just this thing that lit your evenings it was this thing that you cooked with and it was this thing that you paid your taxes with and olive trees are very valuable in that sense because they're so vital to the life at the time but also they you know takes about 10 or 20 years to from planting to get a crop that's reliable so if you if you if you inhabit a land and your ancestors are giving you an olive oil and you're relying on it and you've got this plantation you then have to defend it because if someone then comes in another army the thing they can take from you is the olive oil and of course let's face it everyone is after light after dark so actually it pays for armies it pays for everything this becomes the currency and when you look at the Middle East and you look at the archaeological you find huge jars made of terracotta which stored the olive oil and this is also another great thing about the oil is that it could be stored for years and still being good States so you could you could you could store it up a bit like money but so it's a liquid it's vital in to form as many things in their society but it's still quite you know it's still quite a low flame and this is sort of you know eighty eight hundred nine hundred ad for another thousand years all across the world people use these technologies or you know oil lamps and candles and no one has a better way of lighting the indoor space until this guy called argon comes along from in Switzerland and he suddenly starts to think critically about the candle and the oil and the and the oil lamp and he starts to think well you know this yellow flame is is okay but could I make it brighter and the experiments were trying to get more oxygen into it and he finds that actually if you can draw more oxygen through it this lamp gets this this candle and and light gets brighter and brighter and brighter so we invent a type of lamp called the argon lamp where there's a wick that's circular not a single work so you've got a lot more area and the oxygen comes in through the middle of it and you can see immediately that that's going to yield you and it had the brightness of 10 candles so people start to really like this it starts to be the the thing they use and of course the middle classes in Europe are getting richer and they want to do stuff in the evenings they want to read in particular and be educated they want to play music they want to darn they want to you know play cards and so the evening life of a you know of a up in class middle class or upper class family is dominated by how many lamps you can afford how bright they are but it isn't just in in homes that is important and this is where we're back to the Royal Institution is that in in the mines of course if you go down in your mining it's complete darkness down there and what were they using they were using first candles and then lamps but of course when you're down there mining for coal actually there's a stuff called damp gas which was which was it's basically methane that comes out of the seams and in certain conditions it can accrue and they couldn't smell it and then all of a sudden there'd be an explosion because of the lamp wood would ignite at all and so there was a big as mining went up and this as the kind of the Industrial Revolution took hold and people wanted more coal they wanted more safety in the mines it became a national crisis and this is Humphry Davy's he was here at the Royal Institution it's time he was he was an innovator in in batteries and many other aspects of chemistry but he then took it upon himself to try and solve this problem and this is one of the early prototype where this is a replica of an early prototype of the so-called Davy lamp which ended up and he wasn't the only one who optimized this design I have to say but he did make some really important discoveries here about the fact that if you pull what why this works is that if you pull an ignitable mixture of methane through this gauze instead of exploding it actually it ignites in a controllable way so you can take this down of mine and if there is I've just broken it now I feel bad if you take this down of mine and there's methane the methane comes in it ignites but it doesn't explode so basically you can't get a flame coming out from it and that that's because of the conduction of this of this metal mesh so so Humphrey Davy works that out with some other inventors and they save millions of lives by making the mines more easy to have light in but we're still in this thing where either it's a candle or it's oil and people want more light and some people who are who are whaling at the time realize that this the oil you can get from a whale has a honey-like consistency which is very amenable to an oil lamp it's got it's kind of it's it flows really well and it has a so called flashpoint of 220 degrees now what does a flashpoint mean it just means the temperature have to get it to before it ignites and in the case of olive oil that flashpoint is much high it's like 300 degrees and so that is what gives you the smoky flame it's also what makes it good for cooking by the way if you have a low flash point oil then you can imagine you're cooking a bacon and eggs or whatever you're cooking and if a bit of flame comes into the pan you can get a combustion there and we've all I guess we've all experienced that at some point but the lower the flashpoint of your oil the more like that is to happen so a 300 degree oil is going to be a safe oil and in fact how often if you sort of knock over some oil in your kitchen are you really worried about a fire being caused very low but it turns out that whale oil has this nice combination of a low flash point so you can get a very bright flame and a good capillary action and so it becomes this thing that is changing the way that people behave in their homes at night and people clamor for this whale oil and they start killing whales on an industrial scale really only two fuel people's evening life in Europe and North America and they end up killing quarter of million whales so that people can have more light to play cars read books and do all this stuff and what that tells you is that partly because that they're just you know it's just some beggars belief that no one questions this but also that their thirst for evening light was so great don't forget that underneath the ground all the time near these mines in in the middle east and up here there was a seeping oil stuff that people knew occurred and and could be used al resi had already shown it could be used but no one used it but this clamor for whale oil and the destruction was caused and the market made people realize that they should really have a go at this and so what happens is people do start to get this oil out of the ground and they start to distill it and it is this distilling of this oil that creates what created kerosene so kerosene was put into into oil lamps and it it created this new way of lighting indoor space and it's still still today kerosene or aviation fuel is still used by 300 people worldwide for their indoor lighting so what is it what is this stuff we're talking about well I took I just talked a bit a minute ago about the stuff called methane which is a gas and that's this is this is a representation of it up there and that is a carbon atom with four hydrogen atoms around it and the reason why that's flammable is that the carbon and the hydrogen would like to react with the oxygen in the air and if you give them some energy they'll do it and they'll create carbon dioxide and water so methane and that's the gas that comes out of your your cooker if you have gas at home or if you have central heating fueled by gas its that molecule you're burning but that wasn't available at a time this is got three carbons so you can see there's a branch and there's three carbons there and that and then and and and and a number of hydrogens around it that's also a gas and that's propane and so if you go camping and you get propane gas on the cinder that's what you're burning and that's a more powerful gas that each molecule has more energy in it and and this one here is hexane right so there's six carbon atoms so what is crude oil well if we keep increasing the number car answers what you see is that these long chain carbon has with hydrogens it's a mixture so if we go to we just go to the visualizer for a minute you don't mind so this here is is a little vial of crude oil that they were pumping out the ground at that time and what they were doing is preventing whales being slaughtered and distilling this stuff as I already did into these different components so first of all comes the gases off and then comes these volatile liquids that are colorless and the more you distill the more you get the longer stuff until you end up with sludge if we go back to the presentation and the sludge at the end the so-called tar that's the stuff that ends up on the road now which bits do you want it turned out that if you put these very small molecules into oil lamps at the time they exploded basically they were too volatile they didn't bother going up the wick they just went round the side and any light would explode them so they threw away that fraction so called and it's the fraction between 5 and 8 carbon atoms now they didn't know have any use for it but of course a bit later in the century the automobile gets invented and they start to have a use for it and that's what we call petrol so when you get petrol out of the tank what you're getting are these molecules between 5 and 8 carbon atoms the next fraction is is sort of 9 onwards to sort 21 there is it's a heavier fraction it's a denser liquid and it's not as volatile you need more pressure if you're going to use it in an engine and that's the that's the fuel that Rudolf diesel used to make his engine and that's diesel so diesel petrol they use the same sort of ingredients but ones are much heavier molecule than set of molecules than the other but there's a sort of fraction in between there's somewhere between your petrol and a diesel and that's a kind of mixture and that's kerosene and that is very good for oil lamps it's not so good for internal combustion engines or for diesel engines but it also turns out to be really good for jet engines so it exists at the time it's the first fuel for oil lamps that are artificial and it it saves a hell of a lot of whales lives if you've seen these in the distance or being close to them this is what is it look a distillery looks like oil comes in off the coast or is pump or is brought in by ship and then this is the this is the piece of equipment each one of these towers is a cord is like a distillery it sits as you go higher up hit that you're taking off different fractions of those carbon molecules so when you see these in the distance you're going over a bridge often you see them near the coast they are preparing these different fractions for you for your fuel petrol for your diesel or for your well they don't sell kerosene in petrol pumps but so when you look at those when you see the relationship to the petrol pump and and and the history of this subject what you what it's come through is indoor lighting but nevertheless kerosene is there it's it's a highly it's a highly valuable product that's industrially based it saves a lot of whales and then when rocketry comes along and the Russians want to get to be the first person in space what do they look for to get up there they look for kerosene it's a great fuel it's very stable you can mix it with oxygen you can get an enormous amount of power I said before that fuel has ten times the energy density than nitroglycerine which brings us I think to the pre-flight safety briefing again oK you've got this fuel under your seat and in the wings there's a hell of a lot of it are you worried should you be worried well it's not an explosive I suppose that's the thing to say and one is that what does that mean to explosive and explosives is a chain reaction if you set off a little bit of kerosene then the whole lot would go and you would just be in a fireball that's not what kerosene does kerosene has to be interact with lots of different oxygen atoms from the air so a bit like this candle you have to get the oxygen in there for it to actually probably ignite you can throw a lighted match into a bath of kerosene and it won't it won't go into flames in the same way that I couldn't light that candle when I didn't have a wick so in lots of ways you should be relaxed about flying on top of a bath of kerosene what an explosive is is something like liquid nitro glycerine and this is the molecular structure of nitro glycerine and you can see the difference it's these blue and red atoms and the blue is nitrogen and the red is oxygen and there's a hell of a lot of oxygen in there compared to the number of carbons right so the molecule comes self packed with oxygen it doesn't need outside option to get in so even if you just bump it accidentally as the early inventors did you can just explode the lab and many many many people died just discovering this stuff in fact Alfred Nobel who was the student of the business discovered this you know was incredibly worried about his safety as was everyone else but he persevered and why did he persevere because explosives are so important in mining and he realized that whereas before if you wanted to dig a tunnel anywhere you had to hire a thousand people or you wanted to mine some metal you had thousands of people and you had to pay for all of them but with nitroglycerine with with the oxygen already packed in there a small slab of it poked into a wall would cause huge destruction and you'd get make a lot of headway so this molecule nitroglycerine he made in something called Dyne mine and he had it into a he mixed it with wax and he put it into a form a bit like a stick of candle and you could slot it in light it run away blow it up and he made millions and he made so much money in fact that he felt guilty about it because actually most of the destruction of war after that point was nitroglycerine in the form of dynamite and TNT s all the same stuff and he got really worried about this and his legacy so he started something called the Nobel Prizes and he put one for peace and one for Literature and a few for science and they're still going today and it's sort of the pinnacle of being a great scientist is to get one of these he ironically though suffered from some heart problems for which the remedy was nitroglycerine because if you imbibe it it actually does help things like angina and in case you don't believe me it's still on the market I've got some here for you so if we go through the visualizer so this is called nitro lingual there we go and nitro lingual you know the clue is in the title and you're thinking I can't really be nitroglycerine in there but glycerine tri nitrate there it is you wouldn't be allowed to take this on the plane or maybe you would because it's under 100 milliliters strange place the world will get back to that in a minute but nevertheless kerosene is an incredibly you know powerful thing more powerful than nitroglycerine amazingly and that's really why we have this power to fly anywhere in the world you can go to New York you can go to Tokyo you can go to South Africa you can go to Australia you almost don't have to think about it and this plane will take you non-stop and how does it do it it's because this liquid is this absolutely syrup of power that we have in our lives that we tried to make safe but when we don't make it safe you really really see its power and I'm not talking about any old plane crash I'm talking about the plane crash the one that changed to everything the Twin Towers now the planes were crashed into these buildings but they didn't collapse when the planes crashed in it wasn't that they were structurally compromised by the crash they weren't and in fact they were designed not to be they survived but because they had only just taken off they were full of kerosene and that kerosene started to burn and the winds up there started to give it the oxygen and the temperatures went up and up and up until they got to about 800 degrees and 800 degrees is nowhere near steel which is the main structural element these buildings it's nowhere near Steel's melting point Steel's melting points 1,500 degrees these did not melt but the strength of steel at 800 degrees is half the strength of steel at room temperature so at those levels the strength of the steel became half around 800 and once one layer crumpled all of the rest went down and that's because of the power of kerosene to raise the whole of a floor of a building and all the steel in it up to 800 degrees so it must have been a horrendous horrible moment but we saw the power in those buildings so that's the power that you hold when you're in the plane and you're getting the preflight safety briefing so the question is what is this preflight safety proofing I don't think it really is about these crashes in the sea it's very rare that the cruiser Lodge is going to crack all that you're going to smash into the tarmac it's better to be at the back of the plane by the way you have a 30% better chance of surviving anyway which is kind of always nice to know if you're not in first class isn't it but what is this about and I think my take on this is that this is a ceremony like it's got all the hallmarks of a religious ceremony isn't it one all the props are from way back and they haven't changed just like a religious ceremony taymir they are not functional really right they are symbolic we do this stuff because it used to be dangerous but now it's no more and we rehearse what it used to be like and people bring on the different props and they are you know there's there's this kind of script which again doesn't make any sense just like religious ceremonies but that's not the point right the point is it's about a feeling it's about your state of mind what they're really saying is in the airport you were in charge of your own safety you could choose to jump off the stairwell and break your leg or you could try and RAM your head through a window you could drink - you might whatever but now you are no longer in charge your safety you have handed over through this ceremony to us now if we've done our job badly you're going to die but we haven't done our job badly and the ceremony says that it says we haven't done our job badly and I bet you the best ceremony lasts outlasts all of us because I think it really does fulfill this sense that you need something like this in your life when you're about to be bolted onto something with that much liquid kerosene and it's you know it does play that role of kind of settling you down and saying don't worry we're in charge but for how much longer is an interesting question because if you look at the amount that we ask we are burning of kerosene it's a lot and not just kerosene but petrol and these are all the other related fuels it's an enormous amount and of course it's creating sea to emissions that are causing global warming to an a rate that is alarmingly fast so although a thousand years of history and chemistry and wanting light in our evenings and the slaughter of whales call has caused us and brought us to this point where we can fly anywhere and if you think about it a plane is like a magic carpet really isn't it and the genie is that for smokeless fuel so we kind of have made it come true a magic moment we're gonna have to stop we're all gonna have to stop and every time I give this talk my wife says you always scare people who did not fly I'm like that's probably a good thing I think we probably all should fly less if we're going to make a difference in global warming and drive less and everything less so yes that's where we are today and I think you know young people in the audience yeah you are the ones who are going to have to take us out into a new era of flying flying without co2 emissions without kerosene I think and that's going to be exciting rice I think people are not going to not want to fly and not want to go to the moon but they are going to have to do it it's more sustainably but what happens next on the plane is interesting and I'm not going to dwell on it because I'm running out of time but suffice it to say that the book is a journey on a plane you start with the preflight safety briefing obviously and move through the history of kerosene and the chemistry of it but then we get of course to wine because no sooner have you taken off but the drinks trolley rather jolly comes down towards you and you're offered another amazing liquid wine and for those of you who doubt secretly but haven't said it yet well but will in the in the in the questions who doubt that that's preflight safety briefing has got nothing to do with safety can I just remind you that they spend a lot of time asking you whether you are fit and able to open the exit door and therefore are able to sit by the exit and you have to be yes I'm fit enable and then the next they're selling you a drink not even selling you giving you allowing you to drink as much you like of this drink that's going to make you intoxicated and no one says hold on it if you're drunk you're not going to be safe you're not know which way the exit is or how to open that door with the funny big red handle no because it's not about that but anyway so what is this stuff well alcohol it turns out is actually very similar to kerosene that's because but now now we've got the carbon backbone we've got the hydrogen but we've got this red thing there which is oxygen as you know and that wrecks oxygen o H there is what makes this interesting this this alcohol in here it's about 13% because when you drink it the carbon bit likes your cells because you're made of carbon and so it quite easily finds its way through your system but the O H bit co h bit wreaks havoc in your system in your physiology and you get poisoned it's toxic that's why it's called intoxication you poison yourself but in a nice way in a way that we've all accepted is good so there's lots more to say about this actually but I I feel I'm running out of time and we can get back to this a few provocations then one is that wine and the cost of it how much you should spend it's mostly marketing if you spend more than 10 or 12 pounds on the bottle of wine you're buying you're buying a dream you may like that dream that's your but you're not buying better wine and blind taste tests show this every single time before Christmas the latest one was blind tasting of champagne from Verve Kiko you know hundred pound bottles of wine to go up blind which one comes out best co-op 1999 so and the other thing I want to say to sort of just priek is that one of the one of the chapters is about liquid soap now I can see in the audience there are people like me who were born before liquid soap be ELLs I call us before liquid soap and we knew what those indents in the sink was for they were for a bar of soap and that was natural and normal to find them there but then someone decided that a bar soap was just not good enough and that they would invent a better soap a superior soap and they invented liquid soap in fact this is a good soap actually it was always around but they invented this the pump dispenser and that sold it to us and ever since then liquid soap has insinuated it first of all it was it was the rich people I remember going as their houses and seeing it and thinking whoa and then it was the less rich people and then us and then everyone now is forced to use liquid soap including at the Royal Institution I have to say cuz I took this from the loos and there are lots of reasons that we should not be using liquid soap anymore I elaborate them in the book and we can talk about them but one day it'll be over for liquid soap I'm absent anyway thank you very much I'll end there and take questions [Applause]

Channel: The Royal Institution

Views: 92,434

Rating: 4.1077695 out of 5

Keywords: Ri, Royal Institution, mark miodownik, liquid, physics, materials science, kerosene, wine, water, h20, candles, science lecture, lecture

Id: vNEOk1gnlcw

Length: 56min 5sec (3365 seconds)

Published: Wed Jul 17 2019