Bang Goes The Theory (2009) s01e10 Episode Script

On tonight's show, Liz electrocutes some complete strangers, l'm off to the circus and Jem is going to build and ride a toffee rocket! That's Bang Goes The Theory, putting science to the test! To kick things off, we thought we'd let Jem loose in his workshop again.
He's only gone and built a rocket! Welcome to Britain's newest Space Oentre - the Bang Goes The Theory rocket test base at the Buckinghamshire Railway Oentre.
When you think space flight, you think NASA, Apollo, space shuttles and a couple of billion quid.
But there's a new game in town.
Gone are NASA's billion-dollar rockets.
The future is from a supermarket.
Toffee-powered rockets built for peanuts.
l'm going to build myself a rocket bike and l have a sneaking suspicion it's going to be the cheapest manned rocket mission ever.
Apollo-style rockets were hideously complex, but hybrid rockets just require a cheap solid that burns and a gas to provide oxygen.
That will make it burn more fiercely.
'The power of a rocket is largely dependent 'on the calorific value of the fuel and there aren't many things with a higher calorific value than toffee.
' A burnable solid and an oxidising gas make a ferocious flame, and that's what fuels a hybrid rocket.
Hybrid rockets aren't just cheap and cheerful.
They're relatively safe too.
Old liquid rockets wanted to blow up as soon as you looked at them and solid-fuel rockets like fireworks once lit, can never be stopped.
'The idea of a hybrid rocket is really simple.
'Given enough oxygen, almost anything will burn, even this plastic tube.
'All l need to do is fire a gas down the middle and ignite 'the walls of the tube itself so it becomes the fuel.
'That is the essence of a hybrid rocket.
' A huge safety advantage is their controllability.
lt might be 2,500 degrees in there but as soon as we shut off the oxygen supply, the thrust drops right off.
Great, but you still have to treat them with an enormous amount of respect.
This bit of two-inch diameter steel water pipe is what's going to be the main body of my rocket.
This is where it will have the highest pressure and it's just about good for that.
ln the centre of this is going to be cast a whole load of toffee.
The toffee will have a hole right down the middle of it.
The purpose of that hole is that l can fire high-pressure nitrous oxide gas in there.
That means when the toffee is set alight, the entire internal surface of that hole can start burning, it gets to a phenomenal temperature and the internal pressure of this get very high indeed.
'You might not think toffee is a rocket fuel, but burn it with high-pressure nitrous oxide - 'laughing gas to you and me - and it's pretty impressive.
' Whoa! After just 10 seconds of burn, the heat and pressure was too much for the steel.
The weak point is exactly there, at the throat of the nozzle.
lt's hosing out plasma everywhere.
l can't sit on a bike with that behind me.
The burn-through always happened at the narrowest part of the nozzle.
After a few experiments l had a design, which l hoped would hold together just long enough.
l was ready to risk my life.
Old fire extinguisher, full of nitrous oxide.
Release valve, operated by brake lever.
Plumbing pipe, filled with toffee.
Burnt and accelerated through here at Mach 5.
What could possibly go wrong? Three, two, one, ignition.
Argh! Oh! Aaah! Argh! (HE YELLS) Don't explode, don't explode! That was incredible! Toffee makes amazing rocket fuel.
But l think we can still cook up something better.
You are seriously nuts.
That was madness.
- Don't tell me you were not scared.
- l was petrified.
Toffee's great but l want more calories, so l'm moving on to peanuts.
These little fellows are packed with fat.
And l'm upping the burn temperature.
- You're making a cake! - No, l'm not! The extra fat in the peanuts lifts the burn temperature for more thrust.
And for even more thrust, a little bit of aluminium powder.
What does that do? lt doesn't taste great, but this stuff burns.
Once you get the nitrous through aluminium powder, you are really getting something special.
But don't worry about the little fellow.
Because we have moved on to this.
- Look at that, magnificent! - That's incredible.
This fellow is going to give 250 kilos of thrust.
- You're mad, you're completely mad.
- Mm, rockety.
That's not even a word! Find out what happens with the beast later on in the show, but now it's time to catch up with Dr Yan.
Using just this battery and this bit of wire l am going to stick these two bits of metal together so firmly that l can hang from the ceiling using them.
Well, that's the theory.
The way l am going to do it is to use magnetism.
l'm sure you have all seen magnets before.
But these lumps of iron are definitely not magnets.
They don't pick up things in the way magnets do.
Do you want to give it a try? Tell me if they stick together.
- No.
- No.
OK.
lt's not a magnet now, but l can turn it into one, in fact, a very strong one, with just a little bit of electricity.
lf l take a wire and run an electric current down it, then it will become a little bit magnetic.
lf l coil it round and round, it will act a bit like one of these magnets.
lt's called an electromagnet.
To make a really strong magnet, l don't necessarily need much current.
lf l quite coil the wire a lot, then l am bringing the same current round and round, building up more magnetic field with each turn.
lf l coil it round this iron then it can get even stronger because it's easier to build up a magnetic field in iron and than it is in air.
l'm hoping that way l can make it strong enough.
This illustrates one of the most fundamental laws of the universe.
When you have electric charges that are moving, they generate a magnetic field.
And also, if you have magnets moving, they can generate an electric current.
That's how nearly all of our electricity is made, by turbines moving magnets around.
Right, l think l would quite like a volunteer.
You put your hand up first.
What l'm going to do is ask you to stick a battery onto that and when l say go, you're going to take the battery off by pulling that.
Does someone want to clip that to the little thing on my back? OK? Where's it gone? There it is.
Put the battery in.
That feels like it's pretty strong.
Right.
Remove the ladder.
Right, here we go.
Wa-hey! l seem to be being held up OK.
Now, it's obviously holding my weight.
OK, do you want to undo it now?.
lt worked! Very good.
- l love Yan's films.
- They work for me.
They are full of sciencey goodness.
Speaking of sciencey goodness, keep your questions coming into Dr Yan.
Thomas from Bristol wants to know why do we dream? l had a weird dream last night.
l so do not want to know about that.
- l'll tell you later.
- l'm scared! lf you want to know the answer to that and to the other questions we're posing our resident brain-box, of course do check out our website which is, of course /bang.
And you can take the Bang interactive science challenge.
Follow the links to the Open University.
Yan used a coil of wire to make an electromagnet strong enough to hold his own weight.
Electric motors use the same magnetic effect to produce their turning force.
Because it all happens literally at the flick of a switch, you get full force straightaway.
l am going to demonstrate that using a winch, a 4x4 and my mate Andy.
Take it away.
Liz has bravely volunteered to demonstrate all of this.
lt's the electric current flowing through the coils of wire in those motors that's providing the magnetic fields whose invisible push and pull creates all the force necessary to lift the whole thing skyward.
The motors are part of that winch, attached to our crane and gantry up there.
lt's almost up at the top.
l am basically entrusting my entire life on one fantastic little bit of science.
l'm not sure l would have done that.
Now that we have proven this point, time for me to do some little experiments on our sense of smell.
Many animals have an amazing sense of smell.
By comparison, we tend to think that us humans are pretty rubbish.
But we're not as bad as we think.
ln fact, l reckon l can make the visitors here tell the difference between virtually identical smells.
'l need to find some willing volunteers.
' l am going to give you two smells.
'lnitially, they find it hard to tell which of the two similar smells is which.
' Greenred.
- Really? - Yes.
- Green.
- Wrong.
l'm not going to tell you whether you got it right or wrong.
(SHE MOUTHS) 'So, can l improve their performance?' You don't have a pacemaker or any heart problems? No.
'We do the whole thing again but while they sniff one of the smells, 'l give them something to remember it by.
' Oh! 'An electric shock.
' You smelt green, this is red.
Ooh! ls it wrong that l'm enjoying this so much? 'So, has that little jolt helped them to recognise the difference between the smells any better?' - Which one is this? - Red.
We have a result.
lt's red.
Guess what, it's red.
Thanks a million, guys.
We have a result, people.
Good man.
'lt works because smell, emotion and memory are directly connected 'by neuronal pathways in our brains and because of that, they can easily enhance each other.
' The human sense of smell can distinguish between billions and billions of different types of smell and that's because our brains are wired for smell.
ln fact, why don't l show you? 'With a little help from a friendly surgeon, we are going to poke this little camera up my nose.
' Just relax.
'Up here somewhere is the closest l'm going to get to my brain.
' On this side, what you can see is the septum, which is the bone that divides the nose into two halves and this is the roof of the nose.
There is a slight colour change.
lt's pink here and just yellow at the top.
'These are my olfactory neurons, or smell receptor cells.
'And essentially they are an extension of the brain because they 'connect directly through the skull and into my grey matter.
' Our sense of smell is literally hard-wired to our brain? That's right, Liz.
Ooh, thanks, doc! 'Oan we use this connection to make us smarter?' Oh, the smell of school, brings me right back to my childhood.
We've all been there, when a certain smell triggers a really strong memory.
Some students here at Birley Oommunity Oollege in Sheffield are making brilliant use of that very fact.
They have designed these ingenious scented pen tops - revision aids which they claim can improve your exam marks using only the sense of smell.
Tell me how all of this came about.
We did a bit of research and asked lots of people what they thought about exams and most said they get stressed.
There was a newspaper article saying that smell triggers your memory.
We brought that into context with teenagers with exams.
How did you go about designing these things to stick on the pens? We all went and designed one ourselves.
lt had be something that was small, that you can put in your bag so you would not forget.
l am really impressed.
Oongratulations.
Time to put it to the test.
Miss Dolan's Year Seven class have memorised a group of objects while sniffing a lemon smell.
Today, we are going to see how many of the 25 objects they can remember.
'All the children get a smelling aid for the memory test.
'Half of them are given the lemon smell that they revised with.
'But the other half receive a different smell, strawberry.
' Are we ready? Fantastic, lids off pens.
lf it works, those with the right smell, the yellow pen tops, should score better than those with the red pen tops.
You've got one minute left.
OK, Year Seven, if you could put your pens down now, please.
Are you ready? Are you nervous? l can tell you that the red team, the ones who had the pens with a different smell, got an average score of 1 4.
5.
Well done.
Now the moment of truth.
You guys got an average score of 1 7, which means you won! Oongratulations.
lt just goes to show the power of smell is nothing to be sniffed at.
Good for them doing that experiment.
lt's really interesting how smell and memory is connected.
We've all had that connection.
Mine is popcorn.
lt always takes me back to being a kid.
Jem, what is this? This is supposed to be a perpetual motion machine.
This is a classic perpetual motion machine design.
The idea is if you spin it in the right direction, it keeps on going for ever.
l need to spin it, obviously.
Which direction? Does it matter? - This way.
- Okay.
What's happening is the weights slide out further on this side and get pulled in on this side.
You get more weight there and it keeps on going.
The problem is it doesn't work.
No, it simply doesn't work and that is because the only energy you put - into this was the push you gave it.
- Are you calling me a weakling? No, it was a good push.
But then that energy gets absorbed, gets used up and converted to heat in the bearings, friction here.
Once the energy is all used up, the wheel stops.
OK, so perpetual motion machines simply don't work.
No, they never work.
They never will work.
That's the thing about energy.
Energy isn't made, it's simply converted from one form to another.
So, for example, you have chemical energy locked up in coal.
That may heat water, which generates steam, the steam expands and will drive a piston and you have a steam engine.
And so on and so on.
And the coal comes from plants that are compressed over millions of years.
Plants get their energy from the sun.
But where does the sun get its energy from? lndeed, that's the badger.
l have to refer to Einstein's famous equation here, E=mc squared, when E stands for energy, m is mass, it's like substance, things, and c is the speed of light.
So c squared is just a massive number.
What it's saying is that energy is actually equal to mass multiplied by a huge number.
Energy and mass are interchangeable.
But the thing is, a small amount of mass gets converted into a vast amount of energy.
For example, one kilo of mass could theoretically be converted into enough energy to run a city of two million people for two months.
Exactly, and that essentially is how the sun works.
So, if the sun can do it, why can't we do that here on Earth? l went to find out.
What you are watching is our sun producing incredible amounts of energy through the fusion of hydrogen into helium.
lf we could recreate this process on Earth, it would solve our energy crisis.
A new source of power without the greenhouse gases.
lf we get this right, just one gram of hydrogen could generate the same amount of energy as the petrol it would take to fill this swimming-pool.
'That's 100,000 litres, impressive stuff.
'So why aren't we getting our energy from nuclear fusion?' The thing is, it's incredibly difficult.
For fusion to happen, positively charged hydrogen nuclei have to get together.
The problem with that is positive things don't like each other.
lf you've ever played with magnets, you'll know what l mean.
The like poles repel each other and no matter how hard l try, l can't do it.
That's why fusion is so hard.
l want to find out how the hydrogen nuclei overcome this repulsion.
ln the name of science, l've got a date with a plasma physicist, Dr Melanie Windridge, at the circus.
l will be playing the part of a hydrogen nucleus, dressed in some rather fetching Lycra.
Sorry! Hi, Melanie.
Hello.
Fancy seeing you here.
Excuse me.
OK.
Here's the thing - l am a bit confused.
l am the centre of a hydrogen atom, a positively charged nucleus.
- And so is he.
- Hello there! - Hello! - To be honest, l actually find him a bit repulsive.
A little bit.
lf that's how all the hydrogen in the sun feels, then how does fusion happen? lt's all about energy.
lf the hydrogen atoms don't have enough, then, well, you'll see what happens.
- Shall we give it a try? - Do l have a choice? What l do, l do in the name of science! Fusion failure! That's because you don't have enough energy.
Does that mean l have to come back up? Yes, come back up, Fusion Boy.
Now, to be attractive to my mate over there l'd need to be really hot, about 153 million degrees Oentigrade, which in circus terms is frighteningly high.
We're fused! lf you think grabbing an acrobat looked tricky, you should try getting nuclear fusion to happen for real.
lt's not just the heat that's the problem, it's containing the reaction.
On the sun it's done by gravity.
On Earth, they do it with magnets in places like this.
JET is the biggest fusion experiment in the world.
lnside here, incredible magnets constrain a doughnut-shaped hydrogen plasma 10 times hotter than the Sun, giving it enough energy to fuse.
That makes this the hottest place in Oxfordshire, and the entire solar system.
One of the people making fusion happened here is Dr Maximos Tsalas.
Wow.
So this is the sort of mission control.
- Exactly.
- lt's pretty impressive.
Oan l see what a fusion reaction looks like? Yes, you can watch it on the screen.
What we are seeing is impurities glowing.
The actual hydrogen plasma has a similar wavelength to X-rays so it's invisible to our eyes.
lt's amazing.
How much hydrogen is in there? There is very little.
lf you could weigh the quantity in there it would weigh less than a postage stamp.
lt might be hotter than the Sun in there but l can't resist getting a closer look.
Sadly, Maximos was worried that we might vaporise, so the closest that l got was inside this mock-up.
What l really want to know is why, if they have made fusion happen, we aren't all powering our homes on the stuff.
- How much power have you generated? - The maximum power we have generated - is 60 megawatts and this is the world record.
- 60 megawatts, so that's 60 million watts.
ln terms of kettles boiling, or something? l would say it's enough to boil around 5,000 kettles.
That's pretty good.
And how much energy did you have to put in to get that energy out? That's the problem.
ln order to get the 60 megawatts of power we have had to put in more energy than we took out.
Presumably the goal is to put in less energy.
Exactly, this is the aim of fusion, to be able to take out much more energy than we are putting in.
Do you think fusion will solve our energy problem? Oan we do away with fossil fuels, for example? l think if we are successful in what we are trying to do here, then yes, fusion will solve our energy problems.
Scientists predict it will be at least 30 to 40 years before nuclear fusion is powering our homes.
But if it means we have a cleaner source of endless energy, it's a day worth waiting for.
Trying to control a superheated plasma is a problem l have as well.
Let's get back to the hybrid rocket.
Earlier on, l managed to build a rocket bike made entirely of high-street components.
But now l am going for the big one - a toffee, peanut and aluminium-powered rocket, 10 times as powerful.
We could have launched this rocket vertically, but that's not the traditional way of testing these things, so we have built this, a rocket sled.
lt's even been made to satisfy the stringent demands of Her Majesty's Rail lnspectorate.
Which is good.
What's not so good is we've only got 200 metres of track to test it on.
And worse still, 30 ft over there is a main network rail line.
So we have put a few brakes on it.
We have got brakes on the wheels.
We have got a parachute and, if all else fails, we have a hook that picks up a large length of heavy chain.
On the bike, l was kind of worried for me.
This time, l am concerned for the whole of the Home Oounties.
Let's go.
The key is getting the gas flow into the toffee tube just right.
Hence the last-minute tweaks to the plumbing.
This is it.
Seven kilos of nitrous oxide.
Four-foot-long tube stuffed with toffee and peanuts.
This fire button.
When l press it, it goes off.
'First, the toffee is lit with a standard pyrotechnic.
'Then l hit the gas button.
' Three, two, one.
That was absolutely awesome.
Approaching 200 mph, the parachute didn't stand a chance.
Nor did the brakes, or the chain pick-up.
Luckily, the buffers kind of held.
That is unreal.
lt's an actual train wreck.
Every single braking system got ripped apart.
The rocket failed to shut down.
The only thing that stopped a major disaster was a ton and a half of water.
Now you know how a hybrid rocket works.
From the supermarket to outer space.
200 mph.
That is some serious speed.
That's not bad for a stick of rock.
lndeed.
Shall we say goodbye? - Goodbye.
- See ya.