0:00:02 > 0:00:07Tonight Dallas investigates a global helium crisis and discovers why we should care.
0:00:07 > 0:00:11Running out of helium would be really bad news.
0:00:11 > 0:00:17It has a special property - the lowest boiling point of any known substance in the universe.
0:00:17 > 0:00:22Liz tries out a new, controversial airport security device
0:00:22 > 0:00:26that can see beneath your clothes.
0:00:26 > 0:00:32I am concealing a non-metallic weapon on my person right now that neither detector picked up.
0:00:32 > 0:00:35That's Bang Goes The Theory.
0:00:35 > 0:00:40Hello and welcome to tonight's show. Thank you very much for joining us.
0:00:40 > 0:00:46Now if I were to tell you that helium was running out, you might think, "So what?"
0:00:46 > 0:00:52Fewer party balloons, no more squeaky voices, but there's more to helium than that.
0:00:52 > 0:00:59It's vital for a whole host of hi-tech industries that would really struggle without it.
0:01:03 > 0:01:09These days, we're really used to hearing about natural resources running out - oil, coal,
0:01:09 > 0:01:16rain forest, minerals, tigers. That sort of thing. But did you know helium is a valuable resource, too,
0:01:16 > 0:01:21with finite reserves that are quickly running out.
0:01:23 > 0:01:30I don't know about you, but I've never thought about what happens to the helium inside my balloon
0:01:30 > 0:01:34when I let it go. Maybe I should.
0:01:34 > 0:01:38'Because what goes up doesn't always come down.
0:01:38 > 0:01:45'Although the skin of a balloon will eventually drop back to Earth, the helium inside won't.'
0:01:45 > 0:01:52The helium will continue up to the top of the atmosphere and eventually diffuse off into space.
0:01:52 > 0:01:54Gone forever.
0:01:54 > 0:01:59'Now that is a problem because you can't make new helium.
0:01:59 > 0:02:05'So once we've lost all the naturally available stuff, there simply won't be any left.
0:02:05 > 0:02:12'I'm on a helium mission and it's brought me to Texas and the legendary town of Amarillo.'
0:02:12 > 0:02:18Tony Christie was right. Even with the sat nav, I cannot find the way to Amarillo.
0:02:18 > 0:02:24- SAT NAV: 'Drive 300 feet then turn right.' - That's the way to Amarillo!
0:02:30 > 0:02:34'Amarillo holds the status of being the helium capital of the world,
0:02:34 > 0:02:38'a fact that Tony Christie fails to mention.'
0:02:38 > 0:02:42Running out of helium would be really bad news,
0:02:42 > 0:02:48not just for putting a dampener on kids' parties. Helium has another really important use
0:02:48 > 0:02:53because it has a very special property - the lowest boiling point
0:02:53 > 0:02:57of any known substance in the entire universe.
0:02:57 > 0:03:01In liquid form, its temperature drops to minus 269 degrees Celsius.
0:03:01 > 0:03:05That's only four degrees above absolute zero.
0:03:08 > 0:03:12'That makes it perfect for creating super-conducting electromagnets,
0:03:12 > 0:03:17'which are crucial components for medical MRI scanners.
0:03:17 > 0:03:24'In fact, almost a third of the helium sold every year is for use in MRI and other instruments.'
0:03:25 > 0:03:29Basically, without it we're going to be really stuck
0:03:29 > 0:03:36and if the current global demand continues, we could be facing a shortage in the next 40 years.
0:03:36 > 0:03:42'That's strange because it's the second most common element after hydrogen.
0:03:42 > 0:03:48'A quarter of the mass of the entire universe is helium. Most was formed by nuclear fusion
0:03:48 > 0:03:52'moments after the Big Bang.'
0:03:52 > 0:03:56It is still being created up there, wherever nuclear fusion goes on.
0:03:56 > 0:04:01That is the process that drives the stars, that drives our Sun,
0:04:01 > 0:04:07where you have hydrogen atoms being mashed together to create brand-new helium atoms, but unfortunately,
0:04:07 > 0:04:11that process is really difficult to recreate here on Earth.
0:04:15 > 0:04:22'And that is what brings me here to a place that has more helium than anywhere else on the planet.'
0:04:22 > 0:04:27- Hi, there. It's Dallas Campbell. - 'Come on in.'- Thank you.
0:04:33 > 0:04:39'For such a precious resource, I'm surprised it isn't more heavily guarded.
0:04:39 > 0:04:42'Apparently, the helium is through here.'
0:04:52 > 0:04:58A kilometre or so beneath my feet is a gargantuan helium reservoir
0:04:58 > 0:05:02that stretches out pretty much as far as the eye can see.
0:05:11 > 0:05:15The helium's made by the radioactive decay of heavy metals in the rock,
0:05:15 > 0:05:19which means, apart from anything else, it forms very, very slowly.
0:05:19 > 0:05:25Over millions of years, the gas actually collects in subterranean pockets or reservoirs.
0:05:25 > 0:05:31It's easy to imagine, when you say reservoirs, huge cavernous spaces underground,
0:05:31 > 0:05:36but all we're talking about is areas of porous rock.
0:05:36 > 0:05:42I've got some core samples here taken thousands of feet underground. You can see the porous rock here,
0:05:42 > 0:05:48these tiny little holes, which are perfect for collecting helium or any other gas.
0:05:48 > 0:05:55'Helium naturally forms alongside methane, the natural gas we burn for cooking and heating.
0:05:56 > 0:06:01'In most gas fields, only a tiny fraction is helium and it's hardly worth extracting,
0:06:01 > 0:06:06'but in the 1950s, US miners found levels as high as 7%.
0:06:06 > 0:06:13'There had never been much use for the stuff before, but the arrival of the space race changed that.'
0:06:13 > 0:06:17Helium was very important in developing the atom bomb
0:06:17 > 0:06:23and in the early days of our defence systems and in the space race.
0:06:23 > 0:06:29They felt it was all being wasted, so they developed a programme to extract the helium in Kansas,
0:06:29 > 0:06:36Oklahoma and the Texas panhandle right here, and inject it into the ground right here.
0:06:36 > 0:06:41It sounds really odd that you can actually use solid rock as a storage tank.
0:06:41 > 0:06:49- You take helium from elsewhere and pump it into the ground here. - That was the original purpose.
0:06:49 > 0:06:55'By the time the Cold War was over, there was a worldwide demand for helium in scientific research.
0:06:55 > 0:07:01'Maintaining this huge reservoir was expensive, so America began to sell it off at a rock bottom price.'
0:07:01 > 0:07:06We produce about one-third of the world's helium supplies from here.
0:07:06 > 0:07:12- That's not just America - that's from right here? - From that point in the background.
0:07:14 > 0:07:19'Now the flow of helium is reversed. Instead of pumping it into the ground through this valve,
0:07:19 > 0:07:25'they open the tap and sell it to us.' In theory, could I stick a balloon at the end...?
0:07:25 > 0:07:29In theory, but it would pop very quickly.
0:07:29 > 0:07:36'While the scientific community carefully accounts for every bit of helium used and tries to recycle it,
0:07:36 > 0:07:42'16% of the world's helium is still used in party balloons and airships.
0:07:42 > 0:07:49- 'They can hardly supply it fast enough.'- It goes through this. It's 350 miles long.
0:07:49 > 0:07:52It goes all the way up to Kansas.
0:07:52 > 0:07:58'So at current rates there's about 10 years' worth of helium stored here.
0:07:58 > 0:08:02'After that, there's only the tiny traces found in natural gas fields.
0:08:02 > 0:08:08'That will be much more expensive to extract and eventually it's going to run out.'
0:08:08 > 0:08:14It just feels bonkers to think that here I am standing in Amarillo on one third
0:08:14 > 0:08:17of the entire world's helium supply,
0:08:17 > 0:08:23but things like MRI scanners, cryogenics and high technologies rely on helium so much
0:08:23 > 0:08:27it's a really, really important resource.
0:08:31 > 0:08:38If we run out of helium there, how are these machines which rely on helium going to function?
0:08:38 > 0:08:43That's really the nub of the matter. MRI is so much part of our lives.
0:08:43 > 0:08:48Once the helium we've got stored is used up, a bit like oil,
0:08:48 > 0:08:54eventually it will become really difficult to extract, the price goes up and we're in real trouble.
0:08:54 > 0:08:58Can we not make a lot of helium ourselves in some way? Surely?
0:08:58 > 0:09:06- Only through nuclear reactions. You can either squeeze hydrogen atoms together...- Bare hands.
0:09:06 > 0:09:11..to make helium, and that's nuclear fusion, or you can make it through fission,
0:09:11 > 0:09:15the radioactive decay of larger elements, but we can't make much.
0:09:15 > 0:09:22- Ergo, it's very difficult, then. - Yes.- My advice, next kids' birthday party, book a magician.
0:09:22 > 0:09:26Nonetheless, we have some balloons here. Not helium balloons.
0:09:26 > 0:09:33These two are inflated to markedly different sizes, connected by a pipe with a peg.
0:09:33 > 0:09:37If I remove that peg to allow gas to flow freely between the balloons,
0:09:37 > 0:09:40what happens to their sizes?
0:09:40 > 0:09:45Like many of Dr Yan's brain teasers, think outside the box a bit. This is a good one.
0:09:45 > 0:09:49- Don't give the answer away. - I won't!- Think about it,
0:09:49 > 0:09:53then go onto the website where Dr Yan has all the answers.
0:09:53 > 0:10:00While we're talking about helium and elements, the Open University have put up an all-singing, all-dancing
0:10:00 > 0:10:06- interactive Periodic Table for your delight and delectation. All the details are at /bang.- Nice.
0:10:06 > 0:10:10Let's get back to Dr Yan and his adventures in science.
0:10:10 > 0:10:16This is something I'm interested in - radiation. That word strikes fear in most of us,
0:10:16 > 0:10:21so Dr Yan is testing our perception and knowledge of that word with some of the public.
0:10:21 > 0:10:24Thank you for coming along.
0:10:24 > 0:10:30I've got a couple of things from my high street shops and round about. Nothing unusual.
0:10:30 > 0:10:34There are things here that are radioactive. What I'd like you to do
0:10:34 > 0:10:39is put all the stuff you think is radioactive here
0:10:39 > 0:10:42and all the stuff that isn't over there.
0:10:42 > 0:10:46- An alarm clock?- Radioactive because it's luminous.- Definitely.
0:10:46 > 0:10:48I'd say no.
0:10:48 > 0:10:52- The glow in the dark bit is. - Radioactive? OK.
0:10:52 > 0:10:58- Brazil nuts. Anyone think Brazil buts are radioactive?- No.- OK.
0:10:58 > 0:11:00- Yeah.- We'll put them here, then.
0:11:00 > 0:11:03- A lump of granite?- Yes.
0:11:03 > 0:11:06- Yeah?- It's a little radioactive.
0:11:06 > 0:11:09- Radioactive! Is it not?- No.
0:11:10 > 0:11:13- Some salt? - I'd have said not.- No.
0:11:13 > 0:11:16No?
0:11:17 > 0:11:23- Antique glass bowl? - Er...I'd say it is. What do you think?- What do you think?
0:11:23 > 0:11:25No.
0:11:27 > 0:11:30- How about a smoke alarm? - No...- No.
0:11:30 > 0:11:33It is, but I don't know why.
0:11:33 > 0:11:36- That's probably radioactive. - You think that one is?
0:11:36 > 0:11:39Brilliant. OK, thank you.
0:11:39 > 0:11:43So you've got some of those things right, some not.
0:11:43 > 0:11:47I can show you. Here I've got what is called a Geiger counter.
0:11:47 > 0:11:51This measures ionising radiation, high energy radiation.
0:11:51 > 0:11:54First, this isn't radioactive.
0:11:54 > 0:12:00Lots of people think that the luminous paint on the clock makes it radioactive.
0:12:00 > 0:12:06And it used to be the case that they used radium, but nowadays they don't.
0:12:06 > 0:12:08So that goes right down there.
0:12:08 > 0:12:13And the Brazil nuts. You sometimes hear it said they're radioactive.
0:12:13 > 0:12:19That's because the tree has quite a big root network and takes up minerals.
0:12:19 > 0:12:22The ones from Brazil are often more radioactive
0:12:22 > 0:12:26because it has a little bit more uranium in the ground.
0:12:26 > 0:12:31But these aren't from Brazil, so they're not! I can show you.
0:12:31 > 0:12:36You can see it's sort of between one and two per second,
0:12:36 > 0:12:42but it's not the uranium in this case. It's because all living things, like you and me, plants,
0:12:42 > 0:12:48contain potassium and potassium naturally has a very small amount of radioactivity.
0:12:48 > 0:12:51OK? So next...
0:12:51 > 0:12:54This salt here is low sodium salt
0:12:54 > 0:12:59and they replace some of the sodium with potassium in that low salt.
0:12:59 > 0:13:03And so this...is somewhere between 5 and 10 per second.
0:13:03 > 0:13:05Yeah?
0:13:05 > 0:13:12Now how about the other stuff? Well, this bowl here is made out of uranium glass. Glass with uranium!
0:13:13 > 0:13:18It's not got very much uranium in, but...
0:13:18 > 0:13:20- Watch.- Whoa!
0:13:20 > 0:13:21100.
0:13:21 > 0:13:28So next up is the smoke detector. Inside it is a little pellet of something called americium.
0:13:28 > 0:13:33It's an element. And... it's quite radioactive.
0:13:34 > 0:13:36Oh, no!
0:13:36 > 0:13:41Between 200 and 500 counts per second. But it's giving out a type of radiation
0:13:41 > 0:13:45that doesn't even go through sheets of paper. It's fine.
0:13:45 > 0:13:49Last of all, at the top - granite. People think that's radioactive.
0:13:51 > 0:13:55And you're right. It's got uranium in it. 500 counts a second?
0:13:55 > 0:14:01- You get lots of this in the UK, in Cornwall and places. - That's where I live! Aaah!
0:14:01 > 0:14:06I've got another little treat for you. Down here...
0:14:07 > 0:14:10I've got a tub of nuclear waste.
0:14:10 > 0:14:12HE LAUGHS
0:14:12 > 0:14:15You're only telling us now?!
0:14:15 > 0:14:20- Where do you think this would lie? - It's going to be there. - Way over there.
0:14:20 > 0:14:21Yeah?
0:14:21 > 0:14:26Actually, it's slightly more radioactive than low-sodium salt.
0:14:26 > 0:14:31I'll come clean, actually. This doesn't have radioactive waste.
0:14:32 > 0:14:37I wasn't allowed to bring it out. It's a photo of myself with it.
0:14:37 > 0:14:42You can see about 10 counts per second. A bit more than the salt.
0:14:42 > 0:14:46That's about typical for low-level nuclear waste.
0:14:46 > 0:14:53But if it was high-level radioactive waste, like spent fuel rods from inside a reactor,
0:14:53 > 0:14:58then it would be maybe over a million million counts.
0:14:58 > 0:15:02So right over there, way off the scale.
0:15:02 > 0:15:06The interesting thing is it's a human psychology thing.
0:15:06 > 0:15:13- When people hear the click of a Geiger counter, they react as if their days are numbered.- Yeah.
0:15:13 > 0:15:17It's important to understand that radiation is all around us
0:15:17 > 0:15:23and background radiation doesn't do us that much harm. In fact, we've evolved to deal with it.
0:15:23 > 0:15:25Here's a really good little factoid.
0:15:25 > 0:15:3110% of the radiation we're exposed to actually comes from inside our bodies.
0:15:31 > 0:15:36- If I put it against me... you should be able to hear... - You're nuclear!
0:15:36 > 0:15:39Don't confuse the viewers! I'm radioactive.
0:15:39 > 0:15:43You must distinguish between what's dangerous or not.
0:15:43 > 0:15:47You can kind of understand the misunderstanding.
0:15:47 > 0:15:51Radiation is this sort of invisible, rather mysterious force.
0:15:51 > 0:15:57So next week we've decided to dedicate the whole show to radiation and nuclear power.
0:15:57 > 0:16:04It'll be really interesting. We've had such an amazing trip making that programme. Tune in.
0:16:04 > 0:16:10Our dear Dr Yan, he is going to be a judge on a new BBC project
0:16:10 > 0:16:12to find budding amateur scientists.
0:16:12 > 0:16:16You don't have to be an Einstein to have a light bulb moment.
0:16:16 > 0:16:22Anyone anywhere can have a hunch that's worthy of investigation.
0:16:22 > 0:16:24This is where you'll get the chance.
0:16:24 > 0:16:30It's called So You Want To Be A Scientist. If you have a question you want to research, get in touch.
0:16:30 > 0:16:36All the details are on the website with an interview with Ruth Brooks, last year's winner.
0:16:36 > 0:16:39But you've only got until 31st October.
0:16:39 > 0:16:43For a bit of inspiration, we've got genius British ideas
0:16:43 > 0:16:49that have made it past the research stage. I'm loving this one - this can actually help save lives.
0:16:49 > 0:16:55This is a portable water quality tester. It's been trialled by the University of Birmingham
0:16:55 > 0:16:59in places like remote villages in India and South Africa
0:16:59 > 0:17:05where usually it can take a minimum of five days to get results of whether water is drinkable.
0:17:05 > 0:17:11And it works like this. You put a little bit of water in this tube
0:17:11 > 0:17:15and you sample it. This kit measures the amount of tryptophan in the water.
0:17:15 > 0:17:22It's an amino acid that reflects how much organic matter is in the water.
0:17:22 > 0:17:28You get an idea of the disease-causing bacteria, faecal matter. I think this is fantastic.
0:17:28 > 0:17:33Very good indeed. A little bit less hi-tech, but I love it nonetheless
0:17:33 > 0:17:35is concrete cloth.
0:17:35 > 0:17:40It's a cloth impregnated with concrete. Imagine a disaster area.
0:17:40 > 0:17:44You can inflate temporary buildings like they do with a bouncy castle,
0:17:44 > 0:17:51cover it with the concrete cloth, spray it with water, leave it 24 hours and you get this -
0:17:51 > 0:17:57- a rock-hard skin.- That is amazing. - All the applications for that - brilliant.
0:17:57 > 0:18:03Let's stick with technology and talk about airport security making the headlines,
0:18:03 > 0:18:09not because it's helping us in the war against terrorism, but because it sees through your clothes.
0:18:09 > 0:18:14Great technology or an invasion of privacy? I went to find out.
0:18:17 > 0:18:24'It may be an inconvenience, but these days airport security is part and parcel of checking in.
0:18:27 > 0:18:32- 'And it almost always begins with one of these. - ALARM SOUNDS
0:18:32 > 0:18:36'A metal detector. It's simple enough technology.
0:18:36 > 0:18:41'A huge magnetic field detects anything metal passing through it,
0:18:41 > 0:18:45'spotting anyone trying to hide a knife or a gun.'
0:18:45 > 0:18:46BEEPS
0:18:48 > 0:18:52Of course, metal detectors are great at detecting, well, metal.
0:18:52 > 0:18:54Ah, my radio mic! Thanks.
0:18:54 > 0:19:00But weapons are made of lots of different materials. I am presently concealing a non-metallic weapon
0:19:00 > 0:19:04on my person right now that neither detector picked up.
0:19:05 > 0:19:11Pat downs and full body searches are an option, but time-consuming.
0:19:11 > 0:19:14The last thing you want is extra-long queues for flights.
0:19:14 > 0:19:19What you need is something that can see through my clothes.
0:19:19 > 0:19:23Of course, while you're going through the metal detector,
0:19:23 > 0:19:29your luggage goes through an X-ray machine, which sees through things. How does it do it?
0:19:29 > 0:19:35With cunningly planted objects - a bottle of shampoo, a hair drier and a see-through necklace -
0:19:35 > 0:19:36I'll find out.
0:19:36 > 0:19:42So my suitcase is going through the X-ray machine. What is going on in there right now?
0:19:42 > 0:19:48As the bag has gone into the X-ray tunnel, we've fired X-ray energy at the bag,
0:19:48 > 0:19:51which has gone through the bag.
0:19:51 > 0:19:58As it goes through, it is absorbed at different rates by different pieces of material it contacts.
0:19:58 > 0:20:04So the energy that goes in is different to the energy coming out and we can make a picture.
0:20:04 > 0:20:07What do the different colours mean?
0:20:07 > 0:20:14Orange depicts something that is positively organic. That means something definitely not metallic.
0:20:14 > 0:20:20So most items fall into the organic range. Blue, as you can see here,
0:20:20 > 0:20:23- is something positively metallic.- OK.
0:20:23 > 0:20:27If it's not sure or it's an equal combination, it's green.
0:20:27 > 0:20:30- What are you seeing here, then? - Various liquids.
0:20:30 > 0:20:37You've got a bottle here which looks way outside the legal limit to board an aircraft.
0:20:37 > 0:20:41Yes, it's over 100ml. It's my shampoo.
0:20:41 > 0:20:47- What about over here? What's going on?- We've got a metallic case because it's blue,
0:20:47 > 0:20:52- but what appears to be, to me, a necklace.- Why is it black, then?
0:20:52 > 0:20:57Items that are very dense - lead for example or large lumps of metal - they're black.
0:20:57 > 0:21:02It is possible it's polished metal beads or it could be lead crystal.
0:21:02 > 0:21:08'High-energy X-rays reveal what's inside your luggage because they pass through some materials
0:21:08 > 0:21:14'more easily than others, but they're not an option for scanning passengers.
0:21:14 > 0:21:19'As well as going through your clothes, high-energy X-rays will go through your body
0:21:19 > 0:21:26'and can cause harm. Repeated exposure is very dangerous, so we cannot risk X-raying every passenger
0:21:26 > 0:21:31'on every flight. But X-rays aren't the only option.
0:21:31 > 0:21:36'They're just one part of a whole family of electro-magnetic waves.
0:21:36 > 0:21:41'And with the help of some hosepipe at the airport fire station,
0:21:41 > 0:21:45'I'm going to show you some of the others.'
0:21:46 > 0:21:52Electro-magnetic radiation can be described as energy that travels in waves through space.
0:21:52 > 0:21:58There's lots of different types of radiation depending on its wavelength and frequency.
0:21:58 > 0:22:05The entire range of radiation can be described in the electro-magnetic spectrum.
0:22:06 > 0:22:10'X-rays are among the smallest, just above the tiny gamma waves.'
0:22:10 > 0:22:15Wavelengths here can be as small as one picometre in length.
0:22:15 > 0:22:22The thickness of one strand of my hair is 50 million picometres, so that's very short wavelengths.
0:22:22 > 0:22:28'Almost a million times bigger, light waves are still under a thousandth of a millimetre.
0:22:28 > 0:22:34'Microwaves can be a whole centimetre. Then, finally, there are radio waves,
0:22:34 > 0:22:38'which can be tens or even hundreds of metres long.
0:22:38 > 0:22:42'Each of these waves can pass through different materials.
0:22:42 > 0:22:49'What we need at the airport is something that uses a wave that gets through clothes, but not bodies.
0:22:49 > 0:22:53'And here it is. The millimetre wave scanner.'
0:22:53 > 0:23:00The good thing about this energy level is it's not absorbed by the body, so it's very safe to use.
0:23:00 > 0:23:06It will go through your clothes. Your body is much more dense, so it will reflect the vast majority
0:23:06 > 0:23:12back to the scanner. We then measure that millimetric wave radiation and turn it into a picture
0:23:12 > 0:23:16to look at the contours of your body for anything concealed.
0:23:16 > 0:23:20OK, let's do it before I lose my bottle and run off.
0:23:20 > 0:23:26- I'm going to walk over here. Stand on that circle.- 'So will it spot this hidden weapon of mine?
0:23:26 > 0:23:31'Or, come to think of it, anything else under my clothes?'
0:23:33 > 0:23:38- And stop there.- OK. I forgot to suck in my belly!- It'll be fine.
0:23:38 > 0:23:44- OK, here's the image of your entire body.- But have you found my weapon?- I think so.
0:23:44 > 0:23:48- Have you? Go on.- If we turn it round, I believe you have a knife
0:23:49 > 0:23:55- placed on the small of your back, but between your bra.- Well done!
0:23:55 > 0:24:00It is actually a knife. A ceramic knife, stuck into my bra strap. Awesome.
0:24:00 > 0:24:05- And the radiation found it. - It really did. Excellent stuff.
0:24:05 > 0:24:11'With a new generation of scanners rolling out at airports across the UK,
0:24:11 > 0:24:14'checking in has never been safer or quicker.'
0:24:14 > 0:24:19It's an amazing bit of tech, but it does raise privacy questions.
0:24:19 > 0:24:25- There will be people at home watching that thinking, "I am not walking through that."- I know.
0:24:25 > 0:24:31It is understandable, but for those scanners, the operators of the visual part of the scanner
0:24:31 > 0:24:36are nowhere near the scanner. They never see the individual go through.
0:24:36 > 0:24:40They're always same sex operators. A woman operator looks at women.
0:24:40 > 0:24:47The images are never recorded and also because the whole scanning technology is based on contours,
0:24:47 > 0:24:53your underwear is so close to your body that it helps conceal the more detailed bits of your anatomy.
0:24:53 > 0:24:59Your bits and bobs. Fair enough, but still people will worry. Is it going to be compulsory?
0:24:59 > 0:25:04So far, these haven't rolled out across the UK and the guidelines aren't set in stone.
0:25:04 > 0:25:09Ultimately, it's going to be down to each airport to decide.
0:25:09 > 0:25:14Something I was a bit more curious about is the safe exposure limits.
0:25:14 > 0:25:20Say, for example, I was a frequent flyer going through these things five, ten times a week.
0:25:20 > 0:25:25- Is that too much?- I fly a lot for my job and had the same question.
0:25:25 > 0:25:31These scanners have been rigorously tested and the results are they don't cause you any harm.
0:25:31 > 0:25:38- The operators can stand beside it 24/7 and the health risks are negligible.- There you go.
0:25:38 > 0:25:44We've come to the end of the show. In two weeks' we're in Manchester doing Bang Live.
0:25:44 > 0:25:48We'd love it if you came to see us. All the details are at /bang.
0:25:48 > 0:25:52And you can catch up on one of our favourite projects from the past.
0:25:52 > 0:25:55Remember my coffee-powered car?
0:25:55 > 0:25:584.30am. Time to wake up and smell the coffee.
0:25:58 > 0:26:03But I'm not drinking it. I'm converting it into flammable gas
0:26:03 > 0:26:10that hopefully will get this car 210 miles from BBC Television Centre to Manchester.
0:26:15 > 0:26:20It couldn't have started any better and then gone any worse.
0:26:20 > 0:26:25The car overheats, then we have to pull it onto a truck, then we can't start it again.
0:26:25 > 0:26:32We have a problem with gas quality. We're supposed to be in Manchester, we're not even in Birmingham.
0:26:42 > 0:26:44APPLAUSE
0:26:47 > 0:26:49That was absolutely amazing!
0:26:49 > 0:26:51Guys!
0:26:51 > 0:26:55Well, since that epic journey to Manchester,
0:26:55 > 0:26:59somebody's taken the idea and seriously pimped it up.
0:27:02 > 0:27:09And just a few days ago, Coffee Car Mark 2 made an attempt on a new land speed record.
0:27:13 > 0:27:15ENGINE SPLUTTERS
0:27:15 > 0:27:18True to form, not everything went to plan.
0:27:18 > 0:27:22# Raindrops are falling on my head
0:27:22 > 0:27:28# But that doesn't mean my eyes will soon be turning red
0:27:28 > 0:27:30# Crying's not for me... #
0:27:30 > 0:27:36You can see how it all turned out and get the full story on /bang.
0:27:36 > 0:27:40# Because I'm free... #
0:27:41 > 0:27:45Indeed. As we mentioned earlier, next week is a bit special.
0:27:45 > 0:27:51We're going to look at nuclear power, at radiation - what it is and why it's so controversial.
0:27:51 > 0:27:55- We'll see you then. Bye bye. - Bye.- Bye.
0:28:10 > 0:28:14Subtitles by Subtext for Red Bee Media Ltd - 2011
0:28:15 > 0:28:17Email subtitling@bbc.co.uk