What happens if you urinate on an electric fence? We find out the answer to this and some of your other science questions on this week’s Naked Scientists, including why chilli peppers are red, how does squinting help you see further and what’s the best way to align your laundry with the wind? Plus, why blue food colouring could reduce the damage of spinal injury, how shrimps could catalyse biodiesel production and the physics behind the regularity of raindrops… Like this podcast? Please help us by supporting the Naked Scientists (https://www.thenakedscientists.com/donate)
boldly going where no science show has gone before the naked [Music] scientists hello welcome to this week’s naked scientists and that’s with Helen scales hello Helen hello with Dave anel hi Dave hi Chris and I’m Chris Smith now coming up this week how a blue food dye could actually help to heal spinal cord injuries in the future also how scientists have turned prawn shells into a new breed of high efficiency catalytic converters that can help us to make biodiesel and Raindrops Keep Falling on My Head but how big are they well scientists have made a big breakthrough in discovering what affects the distribution of sizes of raindrops and that’s all coming up or should I say in the case of raindrops coming down in just a second Helen thanks Chris also this week it’s our Science question and answer show we’ll be finding out if peeing on an electric fence or a live rail is likely to result in an electric shock sounds very painful to me and does what a mother eats end up in her breast milk also do animals like whales and dolphins get high blood pressure because they eat too much salt plus we’ll also be answering any questions you have on swine flu Chris is our resident virologist so he’ll be happy to help out with any questions you might have day thanks Helen and in this week’s kitchen science I got a pretty cool party trick for you all you need is a piece of string a mug a nut and a pencil a nut peanut Walnut sort of M8 sort of normal kind of nut put on a metal nut um and I guarantee it’ll be impressive have a go you’re going to tell us what to do with that Presa so nuts and bols from nuty Professor thank you Dave if you’d like to get in touch with us here at the Naked Scientist the email address is Chris at the naked scientist.com The Naked Scientist podcast powered by UK fast the UK’s best hosting provider on the web at UK fast.net now first up this week to the subject of spinal cord injuries and also brain stem and brain injuries in general Strokes for example they’re pretty devastating because the brain has a limited ability to repair itself but one of the major reasons that an injury to the spinal cord is so devastating is because when you do the injury it’s not just the lesion itself the physical damage to the spinal cord that causes a lot of the disability and deficit that follows in fact what happens is that a lot of inflammation ensues and more damage is done because things swell up and because there is already a damage which damages other onward bits of the nervous system so researchers have been looking at a way to try and restore or prevent this secondary damage and a group of researchers at the University of Rochester led by makan neard what they’ve got is a paper in the journal pnas this week showing that a food coloring that’s used to dye food blue in fact this coloring is called Brilliant Blue G and it’s a relative of another food dye which is called FD and C blue dye number one who would have believed it but what you can do with this stuff is to significantly reduce the amount of this second damage that happens when there is damage to the nervous system what this group of researchers have found in recent years is that the reason you get this secondary damage is that when part of the central nervous system is injured you get a release of a family of chemicals called purines including one called ATP adenosin triphosphate which is actually a big energy molecule cells use it to get energy but when it comes out of cells it locks onto a chemical docking station on the surface of other cells in the nervous system and those chemical docking stations are called p2x seven receptors and when these purines lock on what they do is to open up a very big pore like a channel which is on the surface of the cell and this lets lots of calcium go into cells and it makes the cells get very very excited and they go into a cycle a sort of vicious cycle if you like which is called exto toxicity and this ultimately kills the cell so what this group of researchers did was to look at the structure of uh these particular receptors and said well if we can block them and stop this happening we should stop the damage to the cells and they found that these blue food dyes which are already approved for use in in various Industries including putting them into food so we can put them in our bodies they actually block these receptors very effectively so they did some experiments on rats that had spinal cord injuries and they were able to reduce the amount of damage the animals got after the injury they were able to speed up the rate at which the animals got back some of their function following a spinal injury and when they did studies on the actual tissue that had been injured by the injury uh they found that the actual zone of damage was much much smaller consistent with this actually working and blocking this secondary damage if these um dyes are actually having quite a strong drug effect on your body um on the nerve cells do you actually want to be eating them well the difference is that normally these food dyes would be present in low concentrations and they would also be taken in through the diet so therefore the amount that would actually penetrate the tissue would be very low in these animals they gave them the drug via an intravenous route at a much higher dose you can also do it orally but you need a very big dose and then it does get all around your body in fact this blue eye when they studied the nervous system they found that lots of areas including the eye went blue because it was penetrating all the tissue but there is obviously that risk of a side effect but then it shouldn’t be too severe compared with what you’ve got to gain so it sounds like that could be a new way of researching this in the future and helping people with those terrible conditions well you’ve heard about putting a tiger in your tank but now how about putting a shrimp in your tank doesn’t sound quite so impressive does in your tank but indeed um doesn’t sound quite so impressive but it’s exactly what some scientists in China have been doing in an attempt to make biodiesel production more efficient Jin Jen Jang and colleagues from the Hong Agriculture University in Wuhan have discovered that shrimp shells could be a great Improvement on the catalysts that we’re already using to try and convert natural oils that’s from crops like soy sunflowers and rape seed into diesel that we can use in vehicles and use them to drive around how does it work what do they actually do well traditionally what the process that’s going essentially is called trans transesterification and essentially it just means we’re changing the chemical makeup of fatty acids in the seed oils to convert them into a usable Fuel and normally to do that it takes a very long time it’s not really a reaction that takes place very readily so a catalyst is needed and traditionally that’s some kind of strong acid or a base but the problem with those traditional catalysts is that they get used up you can’t reuse them and it involves lots and lots of water actually to to sort of to use those types of catalysts so this new idea is to use shrimp shells um the good thing about them is that they can be reused and they don’t need tons and tons of water because obviously that’s another limited resource something we’ve got to think about using we can’t just use it as if it’s free and hugely abundant and uh and it does seem to work it does seem to actually um increase the rate of this reaction so you can create um this biofuel from these crops and it happens really quite efficiently after 3 hours they converted 89% of a sample of canola oil into biodiesel and they they point out these guys point out that it’s biodegradable it’s quite cheap because it’s actually these are a byproduct of the seafood industry we got shells that we throw off the seafood that we like to eat all the time and it’s quite interesting I’ve actually got the paper here if you had a look at the a picture of this stuff that the the shells are made of and it’s mainly kiteen that’s stuff that our nails and hair is made of but the structure of it inside the the um the shrimp shells is very granular you can see it’s it’s almost like surface area it’s got a very big surface area it’s this grainy um porous structure and that’s how it’s made in the shrimp and so that’s really good for a catalyst cuz you need a surface area for it to for the reaction to take place already really so naturally it’sing burn these things partially to get them down to a sort of carbon skeleton of that presing this very big surface area exactly that’s essentially what they do and it’s quite a simple process doesn’t take too much energy doesn’t have to be heated up too much um so you know maybe this could help in making biofuels a bit more efficient because obviously the biofuel debate rages on it’s a very controversial thing as to whether we should be planting crops and making fuels out of them but it could be part of the debate on how to make um make make less carbon dioxide going into the atmosphere from our from our own Vehicles thanks Helen now in the 19th century scientists studied all sorts of odds and ends and one of the things they looked at was raindrop sizes some of them would go out and get a big piece of blotting paper put it outside during a rainstorm and then have a look at the size of different raindrops they found that whilst a few of the Raindrops Were above 5 mm across most of them were quite small less than a millimeter what was really really strange is that the same sort of heaviness of rain the same rate of rainfall this distribution was always the same so just explain what that means for a second so you’ve got the same range of range drop sizes no matter how hard it’s pelting so say a couple of% of them be 5 millim across 50% of them 3 millimet across etc etc which sounds a bit counterintuitive doesn’t it because you think when it rains really hard you’d expect that to be massive raindrops well the the distribution did change between different rates of rain but for the same rate of rain whichever the shower shower you went Thunder it would be the same you can have rain produced in all sorts of different ways different heights in the clouds and always this distribution was the same now people thought this might be because the big rain drops are hitting each other but people done maths and discovered that they shouldn’t hit each other there’s not enough rain in the sky for them to hit each other enough for them to balance out now Emanuel vilmo at the old Mar university has might have worked out what’s going on he’s saw of an effect which you see in a diesel engine when you squirt droplets of fuel very very fast into air what happen is some of those droplets they flatten out as they go faster and faster and faster and eventually they get so flat they sort of turn into a parachute to blow up into a bubble and they pop and he thought that the same thing might be happening with rain it’s actually a fact I’ve seen in a kitchen science experiment once I was going to say cuz when you were making Rockets yeah I was you made some fast footage yeah I did a highp speed video of a water rocket as some of the drop plits came down and just before one of the last ones on the video hit the ground it sort of blew up into this beautiful bubble and then popped I didn’t I thought this was weird but I didn’t think it had anything important about it but apparently um according to Manuel this is what he thinks is happening in R he he’s done lots of exper with it and the distribution of drops you get from these exp these poppings of these sort of parachutes is exactly what you see in rain so the reason you get that normal distribution of raindrop sizes is because all the big ones fragment into slightly smaller ones the slightly smaller ones may then fragment into even smaller ones and and in the process they’re giving off lots of little ones and and the little tiny ones start sticking themselves together again and they get bigger and bigger and bigger until they go pop and they haven’t actually seen this in Rain yet but there are people flying around in Planes as we speak looking looking at raindrops falling I asked Dave this is important because it’s yeah understanding how rain works is an important thing rain is very important if we understand it more then it might help well I’m going to stick with water but going to the salty water for my second story which is all about how all the swimming things in the oceans might actually contribute to the same amount of mixing in the oceans as all the winds and Tides put together because they’re swimming around and stirring up the sea and that’s all according to kakani Kaa and John dairi from the C Institute of Technology in Pasadena across in the states and their study appeared this week in the journal Nature and it could mean that climate modelers have really been missing quite an important part of the puzzle now what they got up to these guys was they first used computer models to look at a process in which when a body moves through a fluid it actually pulls some of that fluid with him with it um and the more sticky or viscous that fluid is the more of it’s pulled along and this was actually an idea first reported 50 years ago by Charles Darwin no not Charles Darwin himself but his grandson uh and uh well he was a Charles Darwin but yes another one and the computer model showed that even tiny Plankton can pull up to four times its own volume through water just by moving a few body lengths then this is the part of the research that I wish I had been involved in they set off for palao a lovely um island in the Pacific where there are these wonderful tropical Lakes um with jellyfish in them and they’re not being crazy by jumping in with these guys CU these actually have evolved to have no stings at all and I would love to visit them they look absolutely fantastic and they went along there and they squirted luminous dye behind the jellyfish and filmed them with special laser equipped underwater cameras and watched what was going on with the water and it turned out that um about 90% of the water movement came down to Darwin’s theory about B being pulled along as these jellyfish are swimming along in the water and the big question is how does this translate to a global scale sure what difference does it make why does it why is it important yeah I mean we this these guys haven’t sort of specifically scaled this up yet they’re just showing that it’s going on and various research have Wonder are wondering at the moment you know will this actually make a difference but but theoretically if you do think about the number and uh the diversity of different things swimming through the ocean um it could well make a difference there’s actually in nature as well this week There’s a an oceanographer William dewart writes a really interesting commentary of this study so you can go along and have a look at that too and he points out that actually you don’t need very much energy to mix up the oceans they they’re not being mixed up that much if you go just a little bit under the ocean surface and take a cubic kilometer of ocean to mix it up the amount that it does naturally would only take a kitchen blender a hand blender that’s the only amount of energy that the that the waves and everything else is moving the water around so really maybe together all these jellyfish and Plankton and everything else that’s swimming the fish that’s swimming through the sea could actually make a significant contribution by this effect of dragging water along with them and I certainly think it’s very interesting to think that life is having an effect on the world around us thank you Helen and incidentally we’ve actually got some video of that footage of those jellyfish swimming with the Dy being squirted behind them on our website at naked scientist.com so check that out if you want to have a look now also in the news this week The babraham Institute which is located just outside Cambridge have opened a new laboratory and so we sent Ben vler down there to attend the opening and also find out what was going on he’s with us to tell us a bit about it now hello Ben hello um so what was this new center all about well this is the institute’s new bioscience support unit it’s cost 17 million to build and a further £5 million to equip and it contains some state-of-the-art technology including some funky robots that I was watching The babam Institute itself researches various biological mechanisms how they work how they sometimes go wrong and this gives us some insight into things like the causes of cancer the causes of heart disease and actually the way that we age as well now this sort of research underpins development of new therapies and this new bioscience support unit will not only make the research easier and more accurate and quicker but it’s actually designed in such a way to be really flexible which makes the whole thing future proof and should secure that investment for a good while yet The babam Institute itself is funded by the bbsrc that’s a biotechnology and biological sciences research Council they get their money from the UK government and Lord Dron who’s the science Minister was there to open the unit £22 million is a lot of investment especially during a financial crisis like this one but he believes that science is a priority science is vitally important to the UK in part because has to ask the question given the way in which the world’s developing given the UK’s position in 2009 in that world what are the things which the UK is going to be particularly good at what is it we’re going to earn our living in as a country and the answer to that has to be science and the commercialization of Science in terms of innovative due products and services we can’t succeed as a nation by competing on this if you feel like the low Tech side of of life our contribution has to be from those areas where the intellectual contribution the in-depth understanding that we have shown over the decades Britain is particularly good at is our future so my job as science minister is to raise the profile of science to make Heroes out of scientists and science entrepreneurs to get the general public who sometimes see science as a bit of an elitist Endeavor something that’s done by a group of Brainy people but doesn’t really affect them to understand that that we as a nation have to be both scientifically literate because science is going to be so important to our futures but also comfortable in discussing some of the the big issues in science and if we can do that we can continue being a world leader in science and if we maintain our position as a world leader in science we will have I believe a happy and prosperous Society Lord Dron also commended The babam Institute for engaging local schools and The Wider Community because having a future fut proof research facility is only any good if we have a good supply of future scientists he said that there’s one clear way to stay competitive in science in the future continue to invest in and maintain our focus on excellence and making sure that we’re maintaining a strong pipeline of young people coming through from the schools who get excited by science at school that science enthusiasm maintained as they’re growing up studying science universities and coming through to be the next generation of leading scientific researchers if you can develop a sort of scientific approach to living life of of noticing things and asking questions why is that like that even at the most if you like most mundane level I mean thing that’s fascinating me as science minister is that when you you get to meet really brilliant scientists it’s often something early in their life that they noticed which actually got them switched on to science and so the more that we can get people to make that switch go on the more likely we’ll have a you know positive pipeline of young scientists coming forward and that’s going to be very important to our success as a country so it now seems that doing kitchen science experiments with your children is both fun and it’s patriotic that was Lord Dron at the opening of the babraham institute’s new bioscience support unit it’s pretty impressive you got to talk to him I think that’s fantastic I was quite honored actually and he was really nice he was very downto Earth you didn’t get the impression that you know he was there to see the little people at the opening or something he was very much with us very much supporting of what they were doing very much supporting of Science in the UK thank you very much that Ben vler who went down to the babam Institute where they opened the new facility this week and speaking of kitchen science as been mentioned there Dave has got a great experiment that he’s going to show you how to do this week here in the studio plus it’s backed up by a version that you can look at on our website at naked scientist.com don’t forget we’re taking your science questions this week it’s our science phone in Extravaganza we’ll also answer your queries on swine flu if you have anything you’d like to talk about that you can email us Chris theed scientist.com keeping you a breast of the world’s best science the naked scientists this is the Naked Scientist it’s with Chris Smith with Dave anel and with Helen scales don’t forget you can also listen to us online which is in Second Life you go to the Sands at 10:00 on a Sunday morning second lifetime 600 p.m UK time and you can pick up the program live right it’s a bit of the program I love going to put me out of my miseries going on about this nut string and mug for 3 Days telling me I’m going to love it Dave kitchen science time not quite yet you’re not going able to see what happens for another half hour but say say what we’re going to do okay all you need for this kitchen science is a mug a piece of string you want it about as long as from the floor up to your shoulder and a nut as in a metal nut so here I’ve got actually it’s an M8 nut I got out of my G I’m not very familiar with M8 but I can see it’s just a normal looking nut something weight s of 5 or 10 G maybe so I’m going to tie the nut onto one end of the piece of string doesn’t have to be a nut just something which weighs of 5 or 10 gr which you can attach to a piece of string and you’re not too worried about getting broken um and then you just tie the mug onto the other end of the piece of string right if you’re worried you don’t have to use a mug you can use something slightly less damageable does it need to be heavy like a ceramic mug is do something nice and heavy right about the same sort of weight as a mug okie dokie um I’m going to hold the nut in one hand I’m going to hold the pencil in the other hand I’m going to put the pencil underneath piece of string next to The Mug I’m going to stretch my arm out with a nut I’m going to stand up and I’m going to let go of the mug and we’re going to see what happens so let’s just just describe the setup yeah so currently we’ve got Dave standing we’ve got mug in one hand tie to a piece of string the string runs all the way to his other hand where there’s a nut at the end of it on the other other end of the string and he’s holding the pencil which is underneath the string and you’re going to let go of the mug yeah one important thing if you want to hold point the end of the pencil upwards otherwise it’s can fall off the pencil and that’s bad so what do you think might happen I don’t know if I actually want to try this but we’ll find out I’m intrigued actually if if you have a go at this so let’s just just repeat that so you tie the string onto the mug hold the mug in say your right hand and then run the string off of the handle of the mug in your right hand over a pencil also held in your right hand so the string goes over the top of the pencil and then you go out to the right across your body so you got your arms outstretched St string to the other hand with a nut dangling off of it and then you want them to just let go well basically just hold the weight of the U mug with the on the um by the piece of string attach the nut so all the way to the um mugs being hold by the piece of string then let go the nut wow it’s a brave man radio C mug it’s a very nice mug better not to break that it’s not even got any any tea stains on it is quite unusual is unusual around here if you want to have a go and or you have had a go and you’d like to share your results email christh scientist.com and don’t forget any question on anything this week goes so get in touch with your questions as you like we’ve heard from Conrad and he wants to know can proteins ingested by a mother reach the baby in her breast milk I think that’s one for you Chris what do you reckon well the the answer is I was intrigued enough by this and my own observations at home to want to look this up because my wife had been saying to me many times because we now have two small children both were breast said that when she at certain things it seemed to make the children more prone to getting a belly ache and have wind than when she other things I said oh it’s nonsense it’s coming off it’s breast it’s breast milk you know how can that how can that be affected by what the mom eats so I’ve been having a poke around and there’s a paper published in 1921 WR Shannon who found that proteins which are in the mother’s diet can pass unchanged into breast milk and there’s another study which was done kilshaw and Kant they published this in the international Archives of allergy and applied Immunology in 1984 and they they did a very thorough study they took 29 women who are breastfeeding they took samples of their blood and their breast milk and then gave them an egg and half a pint of cow’s milk to drink and then they took samples of both of those um blood blood and breast milk samples again at various intervals afterwards and they measured the levels of these proteins and they used various measures to see whether the proteins were coming through into the breast milk and they found that after the mother at those things they could pick up the egg and the milk proteins intact in her bloodstream between 1 and 2 hours later and it peaked in breast milk four and six hours later so this is really interesting it shows that things that are in the mother’s diet can pass unchanged through into the baby and and why they say that’s important is because this may be a way in which the baby’s immune system gets educated against the things that it will be eating in future because we know that babies when they’re first born have this very plastic immune system that needs to be programmed what it has to recognize as a friend and what it needs to recognize as a foe so this perhaps is why breastfeeding is so important in helping the system get educated like this because the things are presented in the right context at the right time can’t it also be a problem I think I’ve heard a story about um in the Arctic in fact that um some of the Eskimo women there who eat a lot of whale meat um in fact their breast milk becomes what’s classified as contaminated um waste because um some of the contaminants inside the whale meat things like Mercury that build up in those in those animals um living in the sea comes out in her breast milk to to the point that it can be measured and it might even be damaging to their Offspring which is just disastrous the idea of the the the environment being so contaminated and getting through our own systems and I also isn’t there also a story about um how if you have a dram of whiskey that it calms down the if as a mother this is definitely true it calms down the baby I don’t think we necessarily contain that but the way breast milk gets made is that there are specialized cells in the breast tissue which have a very high blood flow the blood goes past the breast cells the cells remove from the blood various chemicals and concentrate them in milk so they they’re using chemicals that come out of the blood water from the blood and they’re making milk but anything that dissolves well in fat can move well through the blood vessel wall through those cells and then into the ducts that that line the breast so therefore drugs and other things like alcohol can end up getting concentrated in breast milk so women have to be a bit careful when they take certain drugs because they can concentrate in the breast milk and what you say about people who eat a diet which may be contaminated of course there’s a risk but you know we didn’t evolve to combat heavy metal poisoning we evolved to give our children the best off the best start in life so I guess that kind of that’s an unfortunate side effect but the bottom line is breast is actually best for the most part now Dave a great question here from Brandon zolinski who says if you urinate on an electric fence will it shock you I can’t see any reason why not and as I grew up in a rural area and it was one thing I was told very very definitely not to do with such Force I have a feeling various people telling me it had personal experience in this area um yeah and the electric fence basically were works by having a wire which is put up to a th couple of thousand volts but with a very very limited current so the current will flow through you but the amount of current that can flow is not going to be dangerous um now electric current will flow quite well through your body because your body’s got water in it with some um salt in there so the salt makes the it’s got ions in it which means electricity can flow through it quite nicely urine is water with some salts in it so electric going to flow through through it quite nicely so yes um as far as I know yes you can get a shock in that manner yes is it is that true where the guy pees on on the Underground and gets a bit of a shock um I don’t would it be fatal is it would would there be enough current flowing in a urine stream do you think to to get I don’t know the underground as much is about 600 volts I think which I would is DC um so I certain I would have thought that there would be plenty there again it depends how well he’s how well the where the current can flow if he’s attached to Earth quite nicely if he’s wearing rubber Wellington Boots probably less likely and will the electricity flow up the urine at the speed of light are you the speed of electricity it should FL the urine at about the spe of electricity yes so it’ be an instantaneous shock I think there’s a kitchen science in this I send Dave out to try and I think we should just take it take the take Dave’s word for it that it does happen so don’t go and pee in the underground thank you very much Helen got a question for you Miguel Navaro says how do marine mammals control their salt intake um he says here um if if you drink sea water it dehydrates you because the salt in the water triggers osmosis at cellular level Etc and and so you have to to get the salt out of your body lose some water to compensate so how do animals like marine mammals that are therefore eating a lot of salt in their diet quite naturally how do they compensate how do they get around there well actually they don’t as far as um we can see they don’t actually do they don’t drink that much sea water at all in fact most um whales and dolphins and things like that really don’t drink uh sea water at all they get most of the water they need in their diet from their food cuz sorts of fish are about 60 or 80% water and you can also get lots of water from Metabolism from oxidizing fat and they have those blubbery layers and that can actually provide them with water so half the time they actually keep their mouths shut but of course some does get in um when they’re eating their food and so on and sea otters apparently do drink quite a bit of sea water um and that’s could possibly be because they actually eat lots of invertebrates um sort of sea urch and things like that and they’re quite salty and high in protein which means they create lots of Uria and to process that um salt and Ura and nitrogen does take a lot of water so they do drink lots of water and um one of the keys really it comes down to their kidneys they’ve got a very different type of kidney to land most land um animals um in that if you look at a human kidney um or most mammals have kind of a a kidney shaped kidney a sort of a single lump um and with with various things going on inside whereas in fact um cations and seals and things um have lots of little bits to their kidneys they very sort of complex structures with lobes UPS of thousands of lobes and each one of those is an individual kidney if you like so they are actually able to concentrate um the fluids in their urine to be stronger than seawater so they do have that ability but they don’t necessarily do it all the time which is actually quite surprising that they don’t have have to do that um you they don’t they they actually just don’t have that much salt in their system in the first place because one thing that um is very often not apparent until until perhaps you read a biochemistry book or something is that metabolism itself produces a lot of water so when you burn sugars you release enormous amounts of water anyway so therefore some animals are very good at using all that water water so their obligatory need to drink is quite low absolutely and they they think that um when C certain seaes and sea lines actually go through long periods when they don’t eat and they’re very much relying on their metabolism and their blubber at that point to provide them with enough water thank you Helen this is the naker scientist science phonin on the way this guess what I haven’t had one of those but it’s a tattoo and we’ll be finding out why it is that tattoos actually don’t fade in the skin whereas if you were to say Mark the surface layers of your skin with a brro or something something we all do by accident half the time why does that fade but actually tattoos ink put into the skin don’t go away what we finding out also on the way why helping to why why squinting helps you to see more clearly and also why Chili Peppers as they get riper and spicier also change into that alluring red color meanwhile got a question or a comment from science Copperfield who’s listening to us in Second Life he had a go of your kitchen science experiment Dave um he doesn’t actually say how this occurred but he says he’s broken his wife favorite mug oops is that a lightly risk factor it is a risk it shouldn’t happen if you get it right just remind people what you want them to do um okay you get take a mug you get a piece of string which is um about the length to your shoulder um put a pencil through um put a pencil under the piece of string hold the the pencil up sort of about a bit above your shoulder hold the other end of the piece of string which you tied a nut or something reasonably heavy 5 or 10 ground to um hold it up let go of the nut see what happens still sounds scary thank you Dave if you’d like to have a go the email address for us with any Science question comments or things you want to say hello to us about here in the studio then it’s Chris theed scientist.com we’ve heard from Kathleen who’s in lowestoft and she said why is it that so many children died in Ireland from tuberculosis that their mothers had well tuberculosis is a bacterial infection it’s an infection caused by microbacterium tuberculosis there’s also another form called bacterium bovis which is actually as the name suggests carried by cows but can occasionally get into humans and people who have TB and specifically open TB in other words they’re actively infected with it they have TB growing in their lungs they’re infectious and these bacteria are absolutely tiny there are many of them and once a person has TB they can remain infected with it for very long periods of time and about onethird of the world’s population is thought to be infected so that’s something in the region of 2 billion people on earth who’ve got TB and those numbers are increasing the death toll because of TB is in the thousands every single day so it’s a very major disorder and it’s a very common disorder because it’s a very infectious disease so if you have infectious cases then you will get onward spread and it used to be a major problem until we did things like testing for it and then vaccinating we give people the BCG which is a disabled live bacterium a micro bacterium which you put into someone and this educates the immune system to help them to react to TB and this reduces the chances of getting a serious dose of TB in the future so that’s how it works Helen you’re listening to the naked scientists and now it’s time to join Laura Soul who’s been finding out about the latest developments in technology this month and she’s been looking into the world of open-source software this month in technology we’re looking at open-source software that is software that you are free to use modify and redistribute yourself at the moment most software is proprietary meaning it is owned by a company you can’t change it and you have to pay to use it recently the alternative open- Source software has been becoming more popular if you’ve used an internet browser such as Firefox or Google Chrome then you’ve been using open source software I spoke to Michael teeman the president of the open source initiative the idea of Open Source software was born as people began to look at the way that software developed on the Internet was developed differently than software developed in proprietary commercial envir environments what people found was that programmers who shared their work and who made their work easily accessible to other people not just to download but also to read and to modify and to understand that began to exhibit a degree of innovation and a degree of quality that was completely unpredicted by backers of the proprietary software model so what are the advantages of using open source the underlying architecture that was designed to be easy for others to work on was a superior way of building software than the traditional proprietary model which was to make things complicated to assume limited access and to assume that only the genius in the Ivory Tower would ever even want to look at the code so why make it clear it seems that proprietary software still dominates the market why do you think this is in the world of Information Technology there are many companies who have been accused and many companies who have been adjudicated to be monopolists and this power of Monopoly which is explained very well in the courts shows that sometimes a monopoly can literally distort free market economics they can bully the market to force the market to do what they want rather than what the market would freely choose if there were a choice that was Michael teeman president of the open source initiative there has been news recently of a new open- source operating system like Microsoft Windows or Mac OS but made by Google and free to download Don Marty chair of the open source World Conference happening in San Francisco in August told me what effect this would have on the market where the impact is going to be is if PC manufacturers pick up on this Google Chrome OS and start putting it on computers that people can buy at their local electronic store if you’ve got a lot of Google Chrome OS being sold to end users well then all the companies that are out there making printers and webcams and scanners and every device that you might want to plug into a computer are going to say well we better get some Linux compatibility on this thing that was Don Marty chair of the open source World Conference Microsoft is probably the most well-known proprietary software company I spoke to Darren strange head of their open sourcing engagement in the UK there are many advantages in the proprietary model there things in terms of being able to take a holistic view of the whole platform and that enables us to deliver products that are more reliable they’re more secure and they’re more consistent in many ways Microsoft on a really interesting journey and I think if you look over the last 10 years we’ve really shifted to being a lot more open to open source and what we’re learning is to be a lot more pragmatic about understanding that we’re not competing against open source as a philosophy that’s like competing against the air we’re competing actually against products so we might compete against Linux we might compete against other products like open office but in the same way we also learn to work with those products too and we’re profoundly optimistic about how Microsoft and the open source Community can grow together for the benefit of our customers that was Darren strange from Microsoft open source engagement finally Michael teeman explained his hopes for open source in the future I Envision a world where more and more companies in the technology world are able to run as largely or fully open- Source companies I think that this idea of continuous innovation is precisely what motivates people to join the open source community and I can tell you that it’s very exciting to people when they realize that the machine that they boot all of the source code that controls that machine is available for inspection that was Michael teeman and before that Darren strange and Don Marty talking to Laura Soul about news of a new open source operating system Google Chrome OS and how the world of open software open source software could change in the future lifting the lab codes on the world’s best science the naked scientists this is the Naked Scientist r chrismith with Helen scars and with Dave Vel it’s our science phone in so if you have any science questions for us then keep them coming in our email address here in the studio is Chris at the naked science scientist.com we”ve actually just heard from Del wav Rider who says that he’s um a trained member of the fire service and going on Dave’s story earlier about whether or not you should we onto electric fences he says that when if it was whether or not you should it was was what the consequences of doing that are exactly anyway um but apparently in the fire service they’re trained not to direct their huge water um cannons their their hose pipes at electric cables um because it can give them a nasty shock as well which is also quite extraordinary to think there’s no salt really in that water maybe a little bit of it’s stack water but very little bit lots and lots of water I suppose in a short amount of time there you go uh slack gigamon is speculating how do we actually make money out of Open Source interesting question don’t know if anyone has any thoughts about this is this software which basically companies are not charging for they’re made available freely um how do they actually have a model which is going to sustain that software and make any Revenue I mean if you you use a lot of this stuff Dave in in what you do what what do you think the answer is to that um there it’s hard to make as much money as you would do by selling stuff but there are various people have models whereby they sell support for the software so if you want it changed and customized for your thing then they they’ll charge for that sort of thing um but yeah it’s generally it is a big problem we’ve got a question here from Reuben and he wants to know could a camera flash move a piece of plastic above it because he says he’s tried this actually when he was a young boy quite a few years ago um and he put a basically put a flash gun it sounds on a flat table and set up a system where he could set it up fire it off when he wanted to put a piece of plastic on top of it and when the flash went off it moved and he’s saying how could a flash how could that work have any thoughts on that I think it’s perfectly feasible because Flash discharges quite a lot of energy um if you take a flash gun and look at the nuts and bols of how it works basically what you’re doing is using a circuit to charge a very big capacitor the capacitor then discharges a fairly high voltage about 300 volts through a gas tube usually Zenon is what she used and this unleashes enormous amounts of energy very very quickly which is why you see this flash of light but what that also does is to produce a lot of heat so what I suspect is going on is that the flash goes off this unleashes some heat this heats the surface of the piece of plastic plus it heats the air separating the plastic and the flash bulb these two things together contribute to both a change of shape of the plastic but moreover a change of shape of the air it expands this may lift up and push the plastic up off the flash a little bit or especially if it’s a light piece of plastic or a piece of paper I mean I did a few simple back of the envelope calculations if you look at the capacitor in a Flash gun it’s about a 1 mad capacitor it’s quite a lot of capacitance and you can calculate how much energy comes out of a capacitor by the equation E equals c the capacitance time V the voltage squared over two so if you put those numbers in with a 1 mad capacitor and you’re using a voltage of about 300 volts that’s actually about 35 Jew of energy that would lift a book about 35 M up in the air if you think about it um because a book weighs is about one about one newton I suppose if you had a light a small paperback so yeah it’s a reasonable amount of work you could get out of it when you do when you do the electrodes on someone’s chest to do a cardiac arrest resuscitation that’s about 300 Jews so it’s uh probably about a fifth of the amount you would use to restart someone’s heart so a reasonable amount of energy I think so I don’t think it’s unfeasible Dave got a question for you from Graham he says why does squinting help you to see more clearly how does it work okay um the way your eye works in the first place is it has a lens at the front lens and the cornerer they act together um to focus light onto the back of your eye basically a lens is a curved piece of transparent material light go slightly slower slower in the lens than um in the air so when light hits it at an angle it will slow down and go around a corner a lens a perfect lens is shaped um so as it focuses all of the light from one point outside your eye to one point on the back of your retina um the problem is as things get closer and further away that you need to change the focus the focus needs to change you need to change the distance um the way your eye does that is by changing the shape of your um lens um the problem comes if you’re shortsighted long-sighted then your lens isn’t the right shape the length of your eye and you can’t adjust enough to be able to see things basically this and so things look fuzzy and but the smaller the iris the smaller area of lens which light can get through the um less less it can go wrong so the less fuzzy less less the errors are so less fuzzy the image is um so basically squint the main thing that squinting does is reduces the area that light can get in through um in the same way if you out on a sunny day if um things look less fuzzy because your iris closes down so if you squint you close down your um eye you let less you let light in through less of the lens so things look less fuzzy thank you Dave very clearly explained b boom this is the nak scientist with Dave anel Helen scales and Chris Smith we’re answering your science questions we also heard from Del Wave Rider who said how much water is actually produced by a human on an average day of metabolism well I can acknowledge a contribution from our wonderful friend the internet here um there’s a book by Paul Insel and Elaine Turner and Don Ross discovering nutrition we just had a quick look in there and their stated figure is about a third of a liter per day is the amount of water that your body makes just through metabolism just by burning sugar because the equation is glucose C6 h206 if you burn that using six molecules of Oxygen Plus 602 this goes to six molecules of carbon dioxide 6 CO2 plus 6 H2O six water molecules and that all adds up to about a third of a liter a day which is why you you get some of the water that you need from actually your own metabolism now something I absolutely adore Helen is the subject of this next question Neil denim says why do Chili Peppers change color when they go right we’re growing some chili peppers on our window so so am I actually my chili plant got some fungal disease and died though or nearly died I managed to resuscitate it but I had to spray something on it that is now um it says do not use on things you intend to eat so although I’ve saved the plant it’s now useless because I can’t actually eat it anyway he says we’re growing some chili peppers and our window cill for ages they’ve been green but suddenly they’re going beautiful red and yellow colors I understand the process why most plants are green but why do the peppers turn red and yellow what’s the point of that excellent yeah I’m growing my own Chili Peppers too failing too as well so if you’ve got any tips on how to do it better I’d love to hear from you but um well if you think about it it’s kind of a two-sided question really first of all why does any kind of fruit or anything that might be eaten um change uh into a bright red color and usually that’s if it’s ripe and ready to go it’s advertising itself to be eaten by a disperser an animal of some sort is going to come along have a nibble eat it take the seeds in its stomach and and release them somewhere else um in the feces to help disperse this plant so that’s okay if you’re a a nice tasty thing like a tomato they start out green and they don’t want to be eaten before they’re nice and ready before the seeds have actually developed enough so they will later on turn to be red and there you go that’s why they turn red but why did chin turn red do they actually want to be eaten given that they’re so spicy do animals actually like to eat chilies well there’s lots of theories about why chilies evolv to have such spiciness in them it’s capsacin is the chemical that actually makes your tongue burn when you have a mouth full of chili and I love it as well and there’s a guy called Josh chuty a scientist in the University of Washington who spent a lot of his time um looking into this question of how spicy Chili’s evolved why they evolved what’s the purpose of them he’s been out into the Bolivian and Peruvian jungles where we think well sorry the rain Forest the dry mountainous areas actually not rainforest um where we think these chilies first evolved and he’s found some really interesting things out we think that it could actually be that mammals are no good at eating chilies um because they actually crch them up their seed Predators that’s not much use to the chili plant CU their seeds get destroyed that way but maybe birds are the ones that the chilies are trying to attract because Birds usually just swallow down the seeds hole um and they don’t actually get affected by the chili and they’ve watched to see there’s there are natural um variations in the amount of um caps and you get in Plants within one population of chilies and if you look they went out and looked and they saw that mammals don’t like to eat the ones where there’s lots of um chili capin in the plants but birds don’t mind they will just go for any of them I think they actually lack the receptor that the capin locks onto on the nerve fibers there you go so they can’t detect it CU one one suggestion we did have for people who um keep chickens and are fed up with rats eating the chicken food is that you put loads of curry powder in with the chicken food and the chickens don’t notice the curry powder because they’re insensitive to cap but the Rats theit of that is that you get a of Premarin chicken so when you come to eat it it’s already nice and Cur super super and it also could be that it deters fungal attack and that in fact um having more capso in the chili plants uh in their seeds helps to avoid um fungus coming along and um and destroying the seed so maybe it’s attracting birds and that’s why Chili’s are red um P could be and we’ve been doing it for an awfully long time at least 6,000 BC we think that the chilies were been cultivated with good reason they’re fantastically tasty thank you Helen Adrian says Dave should I how should I align my laundry with the wind he says as I live in the UK I need to use the dry weather as cleverly as possible for drying my laundry because there ain’t much of this dry weather around if the wind blows from west to east would it be better to place the Rope for the laundry North South or would it be better to do west to east so the wind would dissipate the water Vapors from both sides of the clothing what’s your theory I would have said you probably want it across the wind because if um the wind’s running along your laundry then any moisture evaporates at the front end of the laundry is then going to reduce the evaporation further on um and if you’re going across it then you’re going to get lots of turbulence which um so the air will get to the back fine because it would just go over the top and swirl in the back so but if anyone has any pre ideas then i’ I’d love to hear them yes I’d suggest using a tumble dryer inside which uh is guaranteed to work unlike the washing line in this country oh Chris how about the sunshine come on think of the environment I hang my washing out side in between the rainow this is the Naked Scientist for Chris Smith Dave an when scales if you have some science questions for us then it’s Chris at the naked scientist.com coming up Dave’s wonderful kitchen science mug slashing splashing smashing a bit of rhyming going on there uh experiment for you plus uh we’ll also be finding out why tattoos don’t disappear over a lifetime or du to a lesser or greater extent um quick question from Kathleen who says how come we suddenly have this new medication Tammy flu for swine flu so quickly where did this come from um well the answer is we’ve actually had Tamiflu oel tamivir and there’s another version of that which works in the same way but is made by a rival company and that’s called relenza zanam and these agents were quite carefully designed they were a process of what’s called rational drug design actually what they do is to Target a particle on the surface of a flu virus which is called the neurom minid days and this is an enzyme that sits on the surface of the virus and it it behaves a bit like a machete and whenever virus infects the cell it tries to Bud off or get away from the cell that it’s grown in and in order to do that it needs to make sure that it doesn’t get stuck onto the surface of the cell and also get stuck in any of the mucus which is on the lining of the airway and this enzyme cuts the virus a drift and helps it to get free and the ways Tamiflu works is by blocking up that enzyme so the virus can’t escape from the cell that it’s been growing in and this means that it finds it much harder to spread to other cells and this effectively confines the virus to barracks and so the the infection resses much more slowly it doesn’t infect so many other people it doesn’t infect so many other cells in the same person and therefore the immune system has a better opportunity to try and C tell the infection a little bit uh right I’ve got a question here for you Dave which is on rainbows we’ve had some wonderful rainbows because we’ve had some wonderfully Heavy Rain Rosemary Gant says um what determines the actual shape of rainbow she said she watched one the other night and it was almost flat along the horizon okay um the rainbow is actually always the same shape it’s always a circle um the way rainbow is formed is that when light goes into a raindrop um it kind of reflects around the back and as it come as it goes in and goes out it refracts I mean it bends cuz like go slower in water than it does in air um different colors refract slightly different amounts so the light that comes out of the Raindrop um in different directions it’s slightly different colors so if you look at the Raindrop from a certain different directions it looks different colors if you have a whole Sky Full of raindrops and uh different angles of different colors so if you’re look in different places of different colors um this angle is fixed um it’s about 40 42 degre across the whole rainbow the reason why it’s flat and some sometimes it’s flat and sometimes other is it’s always exactly opposite the Sun so if the Sun is um very is high in the sky then the rainbow is going to be very low if the Sun is very low in the sky then the rainbow is going to be higher up that makes sense and when you see a second rainbow that’s presumably where it’s gone into the Raindrop bounced off the front of the Raindrop gone to the back again and come out the front so it’s done sort of two Journeys and that’s why you get the second rainbow around the first is it’s doing more yeah doing more exciting things inside the rainbow right come on then put us out of our misery with this kitchen science experiment okay so I have the mug um I’m going to have I’ve got a pencil which is going to be going slightly above horizontal um which the mug is now hanging off should I stand back at this point I’m going to stand back I got space to do it in getting a bit tangled up with his headphones there whoops hang on there we go okay so I’m stretching the string out and I’m taking the weight of the mug on on my on the string I’m just going to let go of the nut we’ll see what happen see what happens aha no no broken mug fantastic okay that worked right because the mug and we’ll just explain what happened the mug began to drop off of the the pencil and as it was taking up the string coming from the other hand with a nut on it the nut got close to the end and then began to wind its way around the pencil forming an anchor which arrested the mug as it fell but if you’d held that closer to the ground would it have actually stopped before the mug hit the ground you do you do want to hold it slightly above the length of the string to be safe yes stand on chair now you tell us I hold it I said hold it up okay yeah hold it up above your above the length of the string it’s a great party trick that I would not have guessed that was going to happen I thought it was just going to sort of Swing aimlessly back and forth there was some funny thing I didn’t realize that would happen that was really quite impressive okay what’s going I love it it still worries me when I do it but it is good um what’s going on is as you drop it um there’s two things pulling the nut the nut’s going to get pulled in towards the pencil it’s also dropping under Gravity because it’s dropping under Gravity it starts to rotate around the pencil and as it as a a mug pulls it in the strengthening shorter and shorter and shorter it’s a bit like if you um if you got a ice Gator as they move their weight in towards the middle they spin faster and faster and faster so as the string gets shorter and shorter and the nut gets closer and closer to the pencil it spins faster and faster and faster so it keeps spinning round and round and round the pencil um until eventually it can spin round enough in order to produce enough friction to stop the mug and you have some beautiful wacky pictures of this people look at on I’ve got some lovely highspeed footage of it on the web fantastic so I do have a go and if you manage to make it work send in some pictures of yourself making it work as well right it’s time for this week’s question of the week with Diana o Carol welcome Diana hello hello how is everybody right well this week I’ve been checking out body art to answer this question this is Bruce Rogers of M Pedas California I’ve always wondered why tattoos didn’t disappear over the years so what is it that keeps tattoos in their place hi I’m Neil Walker I’m a consultant dermatologist in Oxford Tattoos by definition are permanent marks produced on the skin by the injection of material by a puncture wound as a dermatologist I see a variety of tattoos not only those which have been applied by a so-called tattoo artist either a professional or amether sober or drunk occasionally I see people who’ve had a black canah tattoo wear a die called PPD is used which can cause nasty skin reactions a properly applied henna tattoo is not a tattoo at all rather it’s a dying process using the paste to produce a design in the dead outer layers of the skin the design Fades as the skin regenerates and that is one of the clues as to why tattoos applied by puncture wounds are permanent our skin is continually regenerating as the outer layers or epidermis grow from basil cells at the bottom to dead horny layer at the top over a period of 6 to 8 weeks pigments implanted beneath the growing layer are in the dermis or supporting layer of the skin and are not removed by the natural process of skin turnover the body recognizes pigment granules as foreign material and there are cells whose function is to remove such material by engulfing them and transporting it to the lymph glands these cells unable to engulf pigment granules over a certain size and therefore the body seems to surround them at a microscopic level by a thin layer of fibrous or scar tissue and they become permanently trapped in the dermis the removal process continues slowly and Tattoos May Fade to a degree over time with different colors fading at different rates depending on the particle size of the pigment in summary tattoos are permanent because the pigment particles are injected under the growing layer of the skin and the body’s mechanisms for dealing with for materials can’t remove the particles over a certain size so size is important D yes basically tattoos stay in the skin because they are held at a deeper level by what is effectively scar tissue and tattoos are not new so uh just to throw a bit of archaeology in there the 5,000-year old ican ITI famously has 57 carbon or so tattoos spread about his body there’s evidence the Egyptians were being tattooed 4,000 years ago the pre-a civilizations 1500 years ago the Romans and the Greeks did it and there are some hints that the Vikings and Aztecs were at it too so with a long history of tattooing here’s something else with the Deep past hi my name is Mike I’m from Oregon in the United States I realize that animals have a very sophisticated immune system te- cells lymph nodes Etc but I’ve often wondered how plants protect themselves from bacteria and viruses thank you so what do you guys think do plants have an immunity to pathogens it’s a brilliant question actually isn’t it because we just take for granted the fact that our immune system has to Ward things off I guess plants produce all sorts of really nasty vicious chemicals for killing things so that could be part of it well they can also commit suicide can’t they plant cells can undergo apoptosis they kill their own cells so I guess one way of protecting themselves is if they detect a virus or something in a Cell they just kill that cell or group of cells and that would wall it off you think I don’t know maybe there’s something that’s ancient enough that we share with plants that animals and plants have brought from a very ancient ancestor in terms of their immunity I don’t know I guess we’ll find out next week thank you very much Diana ra Carol with this week’s question of the week so if you can help us with how do plants ward off microbial attack from viruses bacteria and funguses and things then do drop us a line Chris at the naked scientist.com or you can join in the debate that everyone’s having about it on our Forum you go to naked scientist.com forum and you’ll find there’s a whole board there about question of the week where you can put your thoughts and incidentally question of the week is also available as a podcast in its own right and that’s at nakedscientists qotw or you can find it on iTunes just before we finish uh Judith in Northampton said that when you’re talking about capsacin powder which can be used to stop things eating your chicken food she uses the same trick to stop the squirrels nicking her bird feed and also Dom says what does spray paint contain that makes it burn so well well the answer is D two things one is the propellant the stuff that makes the paint come out of the tin in the first place that’s usually a gas like butane or propane those are the common propellants also used in deodorant which is why deodorants are so flammable uh the other thing that the spray paints contain is that the paint molecules themselves are hydrocarbon based and so they’re very flamable there’s methanol in there too well that’s all we’ve got time for this week we have run out of time so I have to say a very big thank you to Michael Tean Darren strange and Don Marty who talked to Laura about her open- Source software and also to Lord Dron who chatted with Ben earlier this week thank you also to our production team Diana o Caroll Laura Soul Tom Simpkins Ben vler and finally thank you to everyone for listening to us at home we couldn’t do it without you next week Dr cat will be here with a special naked science and after her across the summer we’ll also be joined by various members of The Naked Scientist team who will be bringing us up to date with their favorite bits from the past 12 months plus you’ll also get your chance to hear Ben dancing very badly in the studio again if you’d like to hear any of these programs that we’ve produced this year over again to catch up on any of them they’re all on our website and available as a podcast you can find out more at naked scientist.com podcast in the meantime have a great few weeks and I’ll be back with you in September see you soon and thanks for listening once again goodbye The Naked Scientist podcast comes to you from Cambridge University and is supported by the welcome trust the epsrc and UK fast for more information look us up online at naked scientist.com [Music]