Bang Goes The Theory (2009) s02e05 Episode Script
Season 2, Episode 5
This is Bang Goes The Theory.
On tonight's show, Dallas goes skiing.
Someone put some gates in the way - which slowed me down.
- We've got some work to do.
Jim finds out what powers Britain.
That is just like Longannet power station, only over a billion times smaller.
And l look into last year's flu pandemic.
This tiny parcel containing little more than the genes it needs to replicate can cause serious destruction.
That's Bang Goes The Theory, putting science to the test.
Hello, and welcome to Bang Goes The Theory, another full half hour of adventures in science.
The awesome Winter Olympics in Vancouver.
lnspired me to hit the slopes and lift the lid on the world of ski racing, all in the name of science and technology.
Yeah, right.
Just another excuse for you to put on a pair of skis.
Just watch and learn.
Every year, thousands of skiers, world-class and amateur alike, take advantage of a curious scientific anomaly.
Believe it or not, snow is not very slippy.
But stick a plank or two in your feet and it becomes very slippery indeed.
lt turns out this sudden change is all to do with friction and lubrication.
Friction is a fundamental factor in material science.
lt's the measurement of grip between two materials as they travel across each other.
Something like this hard plastic pencil sharpener and this laminated piece of wood, if l put that on there like that, you can see it travels down very easy.
lt has a low friction coefficient, whereas something like this rubber, put it on the same bit of wood, l can tilt it much higher.
All the way up to there.
We can say it has a higher friction coefficient.
There's another factor to take into consideration.
lf l run my hands together, l can feel the friction like that.
lf l pour a bit of water on my hand, they suddenly become a lot slippier and that is exactly what is happening underneath your skis.
Lubrication.
How do skis become lubricated? One of the other consequences of friction is heat.
When you're skiing along and your ski base is in contact with snow, you're generating a little bit of heat.
That heat melts the snow, so you're skiing on a film of water.
That's what makes you slide along.
The amount of heat the skis generate is surprisingly large.
An average skier on an average slope is generating nearly 300 watts of power.
That's the same as three bright light bulbs under your skis.
Easily enough to melt snow.
ln effect, you're water skiing on hot skis.
To prove the point, l've come up with a cunning experiment to show you the that very cold skis just don't work.
l've managed to get hold of some liquid nitrogen, over 196 degrees below zero, and l'm going to pour it all over my skis.
Probably best not to try this at home.
(ORAOKLlNG) l can hear that crackling.
Here we go.
Let's see what this feels like.
Blimey.
Blimey.
OK.
l don't know if you can see that, it's like skiing on sandpaper.
lt's like somebody has poured glue on the bases of my skis.
Argh! lt's a completely different feel.
lt goes to show that the reason why skis slip is that lubrication underneath your base that's generated by heat caused by friction.
Now l understand how skis work, l feel the need for a little ski challenge.
l'm with Dunblane's finest, Emma Oarrick-Anderson, veteran of four Olympics, and we're going to have a race.
Ready? - l'm ready.
- Let's do it.
Left course, ready? Right course, ready? Go! l made it down in one piece.
l thought you were closer but then l turned around and couldn't see you.
Someone put some gates in the way which slowed me down.
We've got some work to do.
Although l now understand the science of skiing, it clearly isn't enough.
ln an Olympic race, the difference between first and tenth place can be as little as a second.
Emma's kindly agreed to reveal her hi-tech Olympics ski secrets to help me make up some of that time.
Oh, and she's lent me some new skis, too.
Those are your new skis.
How are we going to turbocharge these up and turn me into a world champ? The answer turns out to be an obsessive attention to detail, and that starts with a precision base grind.
Next thing, structure? We're going to put the structure on this.
- Yes.
The tread, if you like.
- That's right.
Structure is the name given to the pattern carved on the bottom of the ski.
Like treads on a car tyre, ski bases need this structure to reduce drag.
How is that going to work in terms of the snow?.
What happens when you're skiing over it because of this? We can see it really well with this one because it's the gross one, the very deep grind.
lf you look closely, you can see the lines coming down here, so the water runs through these grooves and straight off the back.
When fractions of seconds are at stake, it's important to have the ideal amount of water underneath the ski.
Too little, and they're going to be sticky and slow.
Too much, and the water will create drag.
- OK.
Oan we do that? - Yeah, of course.
A really nice one.
Premier deluxe.
- La premier deluxe! - Oui.
- We must win.
- OK.
You must win.
He needs at least three seconds.
l need at least half-an-hour.
After the machine has carved the perfect structure under the base, it's ready for waxing.
The wax you use is going to be specific to the snow type and temperature, and at an Olympic level, has become a dark art.
There are hundreds of different kinds of wax, using different hydrocarbons or fluorocarbons, each with different water-repelling properties, designed for different conditions on the slopes.
On a day like today, we'd be using lo-fluor because the temperatures are quite cold.
You don't need to repel the water very much.
So it's about repelling the water.
The wax is gently melted and then ironed across the whole ski.
After scraping off the excess, it's brushed to force the wax deeper into the porous base.
Now, you can see it's still very dull.
lt's a dull ski still.
lt's fast but it's not super-fast.
l need the super-fast.
l'm relying on you, Michael.
The ski is finally buffed until silky-smooth, and that's as good as science can get it.
You have the best skis, the best wax, the best servicemen But l'm still going to beat you! OK, Emma, l've got my brand-new World Oup giant slalom carving skis.
They've been ground, they've been waxed on, waxed off.
We've got structure, they've been brushed, they've been polished, they've been kissed.
They've been loved.
l think l'm about ready to kick your butt.
Not yet.
There's one last thing.
Lycra.
This Lycra isn't just so l can feel all sexy on the piste - its aerodynamic surface OOULD make all the difference.
Ta-da! Now, with science and technology on my side, l'm beginning to feel l'm in with a real chance.
Go! Even though you beat me that time, these skis make such a difference.
That was great, cos l saw you right beside me after the first gate.
So l knew you were going quicker.
First gate, and then you kicked my butt.
And then l thought l had to up it a little notch.
That was great.
Again, again, again.
Brilliant, Dallas.
But it strikes me that all that ski technology still only works in snowy mountains.
What if we make the whole ski out of ice? Then, it's any slope, any time.
God, that's good.
Leave it with me.
Next up, l wanted to find out how scientists dealt with the swine flu pandemic.
2009 saw a new threat to mankind.
The authorities say there will be more cases and more deaths.
ln March, a new strain of influenza was identified in Mexico.
H1 N1 , or swine flu, had hit the news agenda.
There have been nearly 30,000 confirmed cases, perhaps hundreds of thousands unreported.
Six months later, it had spread to over 200 countries and killed thousands.
And this is what it looks like, the influenza, or flu virus - and it's been around for millennia.
This tiny parcel, containing little more than the genes it needs to replicate, can cause serious destruction.
So how OAN a virus that's been around for thousands of years suddenly cause such chaos and kill so many? The influenza virus doesn't just exist in humans.
Strains of it can also be present in animals like birds and pigs, and if those strains ever combine, that's when a pandemic can start.
lf this is a human strain of the virus, capable of infecting and transmitting between people very easily, and this is an animal strain of the virus, which our immune system is unfamiliar with lf these two strains get the chance to infect the same host cell .
.
and as they replicate, they combine, what you get is a brand-new strain of the influenza virus, and this could cause a pandemic.
And this is what happened in Mexico.
Different strains mixed in a host cell, and what emerged was a new strain.
With early reports of severe illness and death, it looked like many of us would have no resistance to it.
Weeks later, due to the speed of our global transport systems, it spread across the world.
The only thing standing in its way were scientists like Professor Neil Ferguson and his team at lmperial Oollege.
From the moment a new outbreak is identified, it's their job to gather as much data about the virus's behaviour as possible.
From that, they can create predictive models as to how the virus might spread, and what might stop it in its tracks.
How do computer models like this one help us understand the dynamics of a pandemic? The grey represents areas of population, and the red is virus being seeded into that population.
Loads in London.
London and West Midlands, which is where we saw the virus start.
That's because travellers come into those areas predominantly.
lt spreads out into the neighbouring towns.
Oontact between people is key to how a virus spreads.
Most people can infect others two days before and after symptoms begin - an important factor in the models designed at lmperial.
Now we're into June and July and you see the epidemic damping down.
The green areas are areas where there's no longer much transmission, and this is people who are immune.
The epidemic is not yet over though because six weeks later, after the summer holidays, the schools reopen and because the virus was really concentrated in schoolchildren, you get a second wave of the epidemic.
- The map is going red again.
- lnteresting.
Oan you tell me a little bit about how you approach the threat of a pandemic? What's the first thing you have to do? What we do is test interventions.
Whether we should use anti-virals in the population, how much vaccine we should order, what's the likely impact of that vaccine - because we knew we'd only get it in the autumn.
How far might the epidemic have reached before we even had vaccine? So when it comes to a computer simulation like this, is this quite accurate? Unfortunately, no two pandemics are alike.
There was still great uncertainty at the beginning of this pandemic about its exact characteristics.
Lots of people are criticising the response in the UK at the moment because they say we overreacted, we cried wolf.
The difficulty is, very early in a pandemic, you pick up the people who are most sick.
So in Mexico Oity, they picked up deaths.
And there was a real concern, maybe this is a severe pandemic.
We were missing all the people who were mildly ill or not ill at all.
Only as we got more and more data could we tell this was actually a mild virus.
Models can help us estimate how the battle against a pandemic will play itself out, but sooner or later, you've got to fight the virus directly, and to do that, you need to understand how the virus enters and infects our bodies.
The answer lies in the proteins that stick out from the surface of the virus called H and N.
The H protein makes it possible for the virus to enter and infect the cell.
The N protein allows the barriers to exit the cell so it can infect others.
For virologists like Wendy Berkeley, these surface proteins are key to attacking the virus head on, with vaccines and anti-viral drugs.
What can we do to tackle viruses likes swine flu? There are two strategies for tackling a virus.
The first is to use a drug, an anti-viral drug, which you would give to somebody once they were already sick.
And the second would be to use a vaccine, which you would give to people before they'd encountered the virus, but that would protect them if they ever came across it.
So with both those strategies, it involves concentrating on those all-important H and N proteins on the surface of a virus.
That's right.
So how do we go about making a anti-viral drug? How do they work? The anti-virals that we have against influenza virus target the N protein - the one that helps the virus spread through the body and on to new people.
And that allowed scientists to design a drug - what we now call Tamiflu - which would fit into the protein and stop it from working.
The great thing about that drug is it turns out that the hole where the drug fits into is the same shape, no matter whether the N comes from swine flu, bird flu or human flu.
So one drug can deal with all the different influenzas that are out there.
So by simply blocking the function of the N protein, the spread of the influenza virus from cell to cell could be stopped.
Once you have your anti-virals, but you begin to learn more about the virus you're dealing with, you can then turn to vaccines, can't you? Vaccines depend on us making antibodies to the virus, which is part of our own immune response, and saves us from being infected if we encounter the virus in the environment.
We know that antibodies against the H protein are key to protecting us, so to make a vaccine, we grow up the virus in the laboratory, and then we cut off the H protein from the outside of the virus and purify it away.
lf we inject that into somebody's arm, their immune system reacts to that because it's foreign, and they make antibodies which then are present in that person and protect them from infection if somebody sneezes.
As with all vaccines, the key to fighting H1 N1 was to trick the body's immune system into thinking it was being infected by the virus itself, so that our immune system could develop the defences it needed for a real attack.
H1 N1 is now off the news agenda, but there WlLL be another pandemic in the future.
How bad it will be, no-one can tell, but what's for certain is that predictive models and our understanding of those surface proteins will be crucial to defeating the virus.
Wow.
The problem is that viruses are just so unpredictable.
Absolutely.
We'll never know what strain we're going to get next.
But the interesting thing is, there are more viruses on the planet than there are human beings, and the vast majority of them don't cause us any harm.
And if you think about it, they need their host to stay alive for them to replicate and to spread to other hosts.
ln fact, a lot of viruses are vital components of ecosystems.
That makes total sense.
So at what point does a virus become dangerous? Good question.
The problems usually arise when a human population comes into contact with a wild animal population.
A virus is living perfectly happy in a wild animal, causing the animal no harm - and then, for example, we encroach on that wild animal's habitat, we are now host to the virus, and it will probably lead to disease in us.
But that is still a rare occurrence, and we're beginning to understand viruses a whole lot better now so we'll be better equipped to deal with the next pandemic.
Good.
Now for something completely different - it's time to go and see Yan, and this week he's got a chocolate conundrum.
Why are bees like this After Eight factory? Well, inside, these mints start out life as hard, crunchy pieces of minty sugar.
They're not gooey at all.
So how do they go all soft? To find out, we'll need to get into the nitty-gritties of sugar.
This is just ordinary table sugar, and chemically, there are lots of different types of sugar.
This one's called sucrose.
As you can see, it forms hard, crunchy crystals, which is no good if you're after a soft centre.
The sucrose molecule is made up of a front bit and a back bit joined together by a single bond.
On their own, each bit is itself a sugar, but of a different sort.
This one's glucose, like you get in some energy drinks, and this one's fructose.
You often get that in fruits.
The thing is, they don't form crunchy crystals so easily.
So, break this bond, and we can make a nice, smooth paste.
Now, l OAN break that bond using sheer heat.
The problem is, heat and chocolate don't mix.
Hey! Fortunately, there is a more subtle way.
Enzymes are just natural chemicals, and living things produce lots of different sorts.
This one is called invertase, and it's being added here into this vat of minty sucrose.
These are just sucrose squares with a tiny bit of invertase in.
And they're cool and hard, just right for coating chocolate.
This is where they come off the line and they've all been covered in chocolate? That's right.
Oan you pick one up for me? - lt's really hard, isn't it? - lt's much harder than l was expecting.
After this, these chocolates get taken off, put into storage, let the invertase do its work.
What enzymes do is make chemical reactions happen more easily.
So instead of lots of heat, the invertase can break this bond at room temperature.
An enzyme is just like a miniature machine with just the right tools to make the reaction happen.
The invertase grabs the sucrose molecule, bends into just the right position, moves a little bit, and the reaction happens just like that.
Now, invertase just breaks this particular bond in sucrose, but in nature, there are thousands of other enzymes which each help a different reaction happen.
And that includes digestion.
Now it's all soft and just how it should be.
After a few days, the invertase is broken down with sucrose, so now there are no big crunchy crystals and it's all gooey.
But what's that got to do with bees? Well, bees use the same enzyme - invertase - to do the same thing.
Nectar is essentially sugars in water, and to store it to eat through the winter, the bees use invertase to convert the sucrose to glucose and fructose, and then they fan it with their wings to drive off the water.
That makes a soft, gooey paste.
We call ithoney.
Mmm.
Lovely stuff from Dr Yan, there.
Next, l'm off on one enormous power trip.
Ooal has had a lot of bad press over the years, but like it or not, it's still the energy source for the vast majority of Britain's electricity needs.
This is Longannet power station in Fife, the third largest coal-fired power station in Europe.
lt supplies a quarter of all Scotland's electricity, and burns 4 million tonnes of coal a year.
That means this whole mountain of coal l'm standing on is only six months' supply.
And it's not just British coal, either.
lt might all look the same, but the stuff they're shifting around comes from as far afield as Russia, South Africa and Oolombia.
lt arrives on 12 massive trains every day.
At full power, Longannet's furnaces can burn all the coal in one of these wagons in just three minutes.
Each of the massive 600 megawatt generators, enough to boil around a quarter of a million kettles at once, is controlled by just one man and a mouse.
But it's not until you get into the plant itself that those numbers start to make sense.
The scale is incredible.
Each of the four boiler units are over 60 metres high, and the process starts right at the bottom.
When the coal arrives, it heads to these pulverisers which smash it into a fine powder, which is then blown into the furnaces.
The fans are incredibly powerful, lifting tonnes of coal up two storeys or more, to the point where it's injected into the inferno.
Just this one massive coal feeder is sending 25 tonnes an hour to the furnaces.
There are 32 of these.
At full whack, 1 ,000 metric tonnes of coal is fired into the furnaces every hour.
That's like the weight of 1 41 double-decker buses.
Almost at the top of the boiler unit is something l was dying to look into the door that goes right into the furnace.
The energy transfer going on in there is simply astonishing.
And that phenomenal furnace does just one thing - turn water into steam.
So how do you turn steam into electricity? The answer is a steam turbine, which very simply is just a paddle wheel attached to a dynamo, placed in a jet of steam with a bit of pressure behind it.
And that is just like Longannet power station, only over a billion times smaller.
Fire creates heat, which makes water boil , making high-pressure steam, which spins a turbine, and provides power for over a quarter of Scotland.
But there is a downside to burning 4 million tonnes of coal a year.
You end up producing an awful lot of gas.
When you burn coal, you're reacting carbon with oxygen, and the 4 million tonnes of coal they burn here every year becomes, with that added oxygen, about 7 million tonnes of carbon dioxide.
And all of that comes out of these four flues.
ln fact, this one chimney is responsible for a significant proportion of the UK's OO2 emissions.
And that's a big problem, because like it or not, we're going to be relying on coal for our power for many years to come.
But there might just be a way to lessen its impact.
Theoretically, it's possible to extract 90% of the OO2 from the exhaust gases - and that's what's going on in this test facility.
What you're looking at is the start of an experiment which could, at a price, lead to a huge reduction in OO2 emissions from burning coal.
What's going on here is they're literally giving the exhaust gases from the power station a shower.
And it's all to do with chemicals called amines, and they're very good at binding to carbon dioxide.
Nicknamed the Shower in the Tower, as the flue gases rise upwards, a strong amine solution rains down on them.
And incredibly, by the time the exhaust gases have reached the top of that tower, 90% of the carbon dioxide has been absorbed by the tiny amine droplets raining down the inside.
The next stage is to get the carbon dioxide out of the amine solution.
And by warming it .
.
something like that happens.
lt all bubbles out the top.
This is a tiny experimental plant, treating only one six-hundredth of Longannet's gases.
But once they've perfected the technique, they hope to scale it up and ultimately treat every puff of smoke coming from the coal.
- Good bye.
- Bye.
Right, l'm ready.
Seriously guys, why do you think this is a good idea? - Skis made of ice! lt's got to work.
- Good luck, Dallas.
OK Trois, deux, un Geronimo!
On tonight's show, Dallas goes skiing.
Someone put some gates in the way - which slowed me down.
- We've got some work to do.
Jim finds out what powers Britain.
That is just like Longannet power station, only over a billion times smaller.
And l look into last year's flu pandemic.
This tiny parcel containing little more than the genes it needs to replicate can cause serious destruction.
That's Bang Goes The Theory, putting science to the test.
Hello, and welcome to Bang Goes The Theory, another full half hour of adventures in science.
The awesome Winter Olympics in Vancouver.
lnspired me to hit the slopes and lift the lid on the world of ski racing, all in the name of science and technology.
Yeah, right.
Just another excuse for you to put on a pair of skis.
Just watch and learn.
Every year, thousands of skiers, world-class and amateur alike, take advantage of a curious scientific anomaly.
Believe it or not, snow is not very slippy.
But stick a plank or two in your feet and it becomes very slippery indeed.
lt turns out this sudden change is all to do with friction and lubrication.
Friction is a fundamental factor in material science.
lt's the measurement of grip between two materials as they travel across each other.
Something like this hard plastic pencil sharpener and this laminated piece of wood, if l put that on there like that, you can see it travels down very easy.
lt has a low friction coefficient, whereas something like this rubber, put it on the same bit of wood, l can tilt it much higher.
All the way up to there.
We can say it has a higher friction coefficient.
There's another factor to take into consideration.
lf l run my hands together, l can feel the friction like that.
lf l pour a bit of water on my hand, they suddenly become a lot slippier and that is exactly what is happening underneath your skis.
Lubrication.
How do skis become lubricated? One of the other consequences of friction is heat.
When you're skiing along and your ski base is in contact with snow, you're generating a little bit of heat.
That heat melts the snow, so you're skiing on a film of water.
That's what makes you slide along.
The amount of heat the skis generate is surprisingly large.
An average skier on an average slope is generating nearly 300 watts of power.
That's the same as three bright light bulbs under your skis.
Easily enough to melt snow.
ln effect, you're water skiing on hot skis.
To prove the point, l've come up with a cunning experiment to show you the that very cold skis just don't work.
l've managed to get hold of some liquid nitrogen, over 196 degrees below zero, and l'm going to pour it all over my skis.
Probably best not to try this at home.
(ORAOKLlNG) l can hear that crackling.
Here we go.
Let's see what this feels like.
Blimey.
Blimey.
OK.
l don't know if you can see that, it's like skiing on sandpaper.
lt's like somebody has poured glue on the bases of my skis.
Argh! lt's a completely different feel.
lt goes to show that the reason why skis slip is that lubrication underneath your base that's generated by heat caused by friction.
Now l understand how skis work, l feel the need for a little ski challenge.
l'm with Dunblane's finest, Emma Oarrick-Anderson, veteran of four Olympics, and we're going to have a race.
Ready? - l'm ready.
- Let's do it.
Left course, ready? Right course, ready? Go! l made it down in one piece.
l thought you were closer but then l turned around and couldn't see you.
Someone put some gates in the way which slowed me down.
We've got some work to do.
Although l now understand the science of skiing, it clearly isn't enough.
ln an Olympic race, the difference between first and tenth place can be as little as a second.
Emma's kindly agreed to reveal her hi-tech Olympics ski secrets to help me make up some of that time.
Oh, and she's lent me some new skis, too.
Those are your new skis.
How are we going to turbocharge these up and turn me into a world champ? The answer turns out to be an obsessive attention to detail, and that starts with a precision base grind.
Next thing, structure? We're going to put the structure on this.
- Yes.
The tread, if you like.
- That's right.
Structure is the name given to the pattern carved on the bottom of the ski.
Like treads on a car tyre, ski bases need this structure to reduce drag.
How is that going to work in terms of the snow?.
What happens when you're skiing over it because of this? We can see it really well with this one because it's the gross one, the very deep grind.
lf you look closely, you can see the lines coming down here, so the water runs through these grooves and straight off the back.
When fractions of seconds are at stake, it's important to have the ideal amount of water underneath the ski.
Too little, and they're going to be sticky and slow.
Too much, and the water will create drag.
- OK.
Oan we do that? - Yeah, of course.
A really nice one.
Premier deluxe.
- La premier deluxe! - Oui.
- We must win.
- OK.
You must win.
He needs at least three seconds.
l need at least half-an-hour.
After the machine has carved the perfect structure under the base, it's ready for waxing.
The wax you use is going to be specific to the snow type and temperature, and at an Olympic level, has become a dark art.
There are hundreds of different kinds of wax, using different hydrocarbons or fluorocarbons, each with different water-repelling properties, designed for different conditions on the slopes.
On a day like today, we'd be using lo-fluor because the temperatures are quite cold.
You don't need to repel the water very much.
So it's about repelling the water.
The wax is gently melted and then ironed across the whole ski.
After scraping off the excess, it's brushed to force the wax deeper into the porous base.
Now, you can see it's still very dull.
lt's a dull ski still.
lt's fast but it's not super-fast.
l need the super-fast.
l'm relying on you, Michael.
The ski is finally buffed until silky-smooth, and that's as good as science can get it.
You have the best skis, the best wax, the best servicemen But l'm still going to beat you! OK, Emma, l've got my brand-new World Oup giant slalom carving skis.
They've been ground, they've been waxed on, waxed off.
We've got structure, they've been brushed, they've been polished, they've been kissed.
They've been loved.
l think l'm about ready to kick your butt.
Not yet.
There's one last thing.
Lycra.
This Lycra isn't just so l can feel all sexy on the piste - its aerodynamic surface OOULD make all the difference.
Ta-da! Now, with science and technology on my side, l'm beginning to feel l'm in with a real chance.
Go! Even though you beat me that time, these skis make such a difference.
That was great, cos l saw you right beside me after the first gate.
So l knew you were going quicker.
First gate, and then you kicked my butt.
And then l thought l had to up it a little notch.
That was great.
Again, again, again.
Brilliant, Dallas.
But it strikes me that all that ski technology still only works in snowy mountains.
What if we make the whole ski out of ice? Then, it's any slope, any time.
God, that's good.
Leave it with me.
Next up, l wanted to find out how scientists dealt with the swine flu pandemic.
2009 saw a new threat to mankind.
The authorities say there will be more cases and more deaths.
ln March, a new strain of influenza was identified in Mexico.
H1 N1 , or swine flu, had hit the news agenda.
There have been nearly 30,000 confirmed cases, perhaps hundreds of thousands unreported.
Six months later, it had spread to over 200 countries and killed thousands.
And this is what it looks like, the influenza, or flu virus - and it's been around for millennia.
This tiny parcel, containing little more than the genes it needs to replicate, can cause serious destruction.
So how OAN a virus that's been around for thousands of years suddenly cause such chaos and kill so many? The influenza virus doesn't just exist in humans.
Strains of it can also be present in animals like birds and pigs, and if those strains ever combine, that's when a pandemic can start.
lf this is a human strain of the virus, capable of infecting and transmitting between people very easily, and this is an animal strain of the virus, which our immune system is unfamiliar with lf these two strains get the chance to infect the same host cell .
.
and as they replicate, they combine, what you get is a brand-new strain of the influenza virus, and this could cause a pandemic.
And this is what happened in Mexico.
Different strains mixed in a host cell, and what emerged was a new strain.
With early reports of severe illness and death, it looked like many of us would have no resistance to it.
Weeks later, due to the speed of our global transport systems, it spread across the world.
The only thing standing in its way were scientists like Professor Neil Ferguson and his team at lmperial Oollege.
From the moment a new outbreak is identified, it's their job to gather as much data about the virus's behaviour as possible.
From that, they can create predictive models as to how the virus might spread, and what might stop it in its tracks.
How do computer models like this one help us understand the dynamics of a pandemic? The grey represents areas of population, and the red is virus being seeded into that population.
Loads in London.
London and West Midlands, which is where we saw the virus start.
That's because travellers come into those areas predominantly.
lt spreads out into the neighbouring towns.
Oontact between people is key to how a virus spreads.
Most people can infect others two days before and after symptoms begin - an important factor in the models designed at lmperial.
Now we're into June and July and you see the epidemic damping down.
The green areas are areas where there's no longer much transmission, and this is people who are immune.
The epidemic is not yet over though because six weeks later, after the summer holidays, the schools reopen and because the virus was really concentrated in schoolchildren, you get a second wave of the epidemic.
- The map is going red again.
- lnteresting.
Oan you tell me a little bit about how you approach the threat of a pandemic? What's the first thing you have to do? What we do is test interventions.
Whether we should use anti-virals in the population, how much vaccine we should order, what's the likely impact of that vaccine - because we knew we'd only get it in the autumn.
How far might the epidemic have reached before we even had vaccine? So when it comes to a computer simulation like this, is this quite accurate? Unfortunately, no two pandemics are alike.
There was still great uncertainty at the beginning of this pandemic about its exact characteristics.
Lots of people are criticising the response in the UK at the moment because they say we overreacted, we cried wolf.
The difficulty is, very early in a pandemic, you pick up the people who are most sick.
So in Mexico Oity, they picked up deaths.
And there was a real concern, maybe this is a severe pandemic.
We were missing all the people who were mildly ill or not ill at all.
Only as we got more and more data could we tell this was actually a mild virus.
Models can help us estimate how the battle against a pandemic will play itself out, but sooner or later, you've got to fight the virus directly, and to do that, you need to understand how the virus enters and infects our bodies.
The answer lies in the proteins that stick out from the surface of the virus called H and N.
The H protein makes it possible for the virus to enter and infect the cell.
The N protein allows the barriers to exit the cell so it can infect others.
For virologists like Wendy Berkeley, these surface proteins are key to attacking the virus head on, with vaccines and anti-viral drugs.
What can we do to tackle viruses likes swine flu? There are two strategies for tackling a virus.
The first is to use a drug, an anti-viral drug, which you would give to somebody once they were already sick.
And the second would be to use a vaccine, which you would give to people before they'd encountered the virus, but that would protect them if they ever came across it.
So with both those strategies, it involves concentrating on those all-important H and N proteins on the surface of a virus.
That's right.
So how do we go about making a anti-viral drug? How do they work? The anti-virals that we have against influenza virus target the N protein - the one that helps the virus spread through the body and on to new people.
And that allowed scientists to design a drug - what we now call Tamiflu - which would fit into the protein and stop it from working.
The great thing about that drug is it turns out that the hole where the drug fits into is the same shape, no matter whether the N comes from swine flu, bird flu or human flu.
So one drug can deal with all the different influenzas that are out there.
So by simply blocking the function of the N protein, the spread of the influenza virus from cell to cell could be stopped.
Once you have your anti-virals, but you begin to learn more about the virus you're dealing with, you can then turn to vaccines, can't you? Vaccines depend on us making antibodies to the virus, which is part of our own immune response, and saves us from being infected if we encounter the virus in the environment.
We know that antibodies against the H protein are key to protecting us, so to make a vaccine, we grow up the virus in the laboratory, and then we cut off the H protein from the outside of the virus and purify it away.
lf we inject that into somebody's arm, their immune system reacts to that because it's foreign, and they make antibodies which then are present in that person and protect them from infection if somebody sneezes.
As with all vaccines, the key to fighting H1 N1 was to trick the body's immune system into thinking it was being infected by the virus itself, so that our immune system could develop the defences it needed for a real attack.
H1 N1 is now off the news agenda, but there WlLL be another pandemic in the future.
How bad it will be, no-one can tell, but what's for certain is that predictive models and our understanding of those surface proteins will be crucial to defeating the virus.
Wow.
The problem is that viruses are just so unpredictable.
Absolutely.
We'll never know what strain we're going to get next.
But the interesting thing is, there are more viruses on the planet than there are human beings, and the vast majority of them don't cause us any harm.
And if you think about it, they need their host to stay alive for them to replicate and to spread to other hosts.
ln fact, a lot of viruses are vital components of ecosystems.
That makes total sense.
So at what point does a virus become dangerous? Good question.
The problems usually arise when a human population comes into contact with a wild animal population.
A virus is living perfectly happy in a wild animal, causing the animal no harm - and then, for example, we encroach on that wild animal's habitat, we are now host to the virus, and it will probably lead to disease in us.
But that is still a rare occurrence, and we're beginning to understand viruses a whole lot better now so we'll be better equipped to deal with the next pandemic.
Good.
Now for something completely different - it's time to go and see Yan, and this week he's got a chocolate conundrum.
Why are bees like this After Eight factory? Well, inside, these mints start out life as hard, crunchy pieces of minty sugar.
They're not gooey at all.
So how do they go all soft? To find out, we'll need to get into the nitty-gritties of sugar.
This is just ordinary table sugar, and chemically, there are lots of different types of sugar.
This one's called sucrose.
As you can see, it forms hard, crunchy crystals, which is no good if you're after a soft centre.
The sucrose molecule is made up of a front bit and a back bit joined together by a single bond.
On their own, each bit is itself a sugar, but of a different sort.
This one's glucose, like you get in some energy drinks, and this one's fructose.
You often get that in fruits.
The thing is, they don't form crunchy crystals so easily.
So, break this bond, and we can make a nice, smooth paste.
Now, l OAN break that bond using sheer heat.
The problem is, heat and chocolate don't mix.
Hey! Fortunately, there is a more subtle way.
Enzymes are just natural chemicals, and living things produce lots of different sorts.
This one is called invertase, and it's being added here into this vat of minty sucrose.
These are just sucrose squares with a tiny bit of invertase in.
And they're cool and hard, just right for coating chocolate.
This is where they come off the line and they've all been covered in chocolate? That's right.
Oan you pick one up for me? - lt's really hard, isn't it? - lt's much harder than l was expecting.
After this, these chocolates get taken off, put into storage, let the invertase do its work.
What enzymes do is make chemical reactions happen more easily.
So instead of lots of heat, the invertase can break this bond at room temperature.
An enzyme is just like a miniature machine with just the right tools to make the reaction happen.
The invertase grabs the sucrose molecule, bends into just the right position, moves a little bit, and the reaction happens just like that.
Now, invertase just breaks this particular bond in sucrose, but in nature, there are thousands of other enzymes which each help a different reaction happen.
And that includes digestion.
Now it's all soft and just how it should be.
After a few days, the invertase is broken down with sucrose, so now there are no big crunchy crystals and it's all gooey.
But what's that got to do with bees? Well, bees use the same enzyme - invertase - to do the same thing.
Nectar is essentially sugars in water, and to store it to eat through the winter, the bees use invertase to convert the sucrose to glucose and fructose, and then they fan it with their wings to drive off the water.
That makes a soft, gooey paste.
We call ithoney.
Mmm.
Lovely stuff from Dr Yan, there.
Next, l'm off on one enormous power trip.
Ooal has had a lot of bad press over the years, but like it or not, it's still the energy source for the vast majority of Britain's electricity needs.
This is Longannet power station in Fife, the third largest coal-fired power station in Europe.
lt supplies a quarter of all Scotland's electricity, and burns 4 million tonnes of coal a year.
That means this whole mountain of coal l'm standing on is only six months' supply.
And it's not just British coal, either.
lt might all look the same, but the stuff they're shifting around comes from as far afield as Russia, South Africa and Oolombia.
lt arrives on 12 massive trains every day.
At full power, Longannet's furnaces can burn all the coal in one of these wagons in just three minutes.
Each of the massive 600 megawatt generators, enough to boil around a quarter of a million kettles at once, is controlled by just one man and a mouse.
But it's not until you get into the plant itself that those numbers start to make sense.
The scale is incredible.
Each of the four boiler units are over 60 metres high, and the process starts right at the bottom.
When the coal arrives, it heads to these pulverisers which smash it into a fine powder, which is then blown into the furnaces.
The fans are incredibly powerful, lifting tonnes of coal up two storeys or more, to the point where it's injected into the inferno.
Just this one massive coal feeder is sending 25 tonnes an hour to the furnaces.
There are 32 of these.
At full whack, 1 ,000 metric tonnes of coal is fired into the furnaces every hour.
That's like the weight of 1 41 double-decker buses.
Almost at the top of the boiler unit is something l was dying to look into the door that goes right into the furnace.
The energy transfer going on in there is simply astonishing.
And that phenomenal furnace does just one thing - turn water into steam.
So how do you turn steam into electricity? The answer is a steam turbine, which very simply is just a paddle wheel attached to a dynamo, placed in a jet of steam with a bit of pressure behind it.
And that is just like Longannet power station, only over a billion times smaller.
Fire creates heat, which makes water boil , making high-pressure steam, which spins a turbine, and provides power for over a quarter of Scotland.
But there is a downside to burning 4 million tonnes of coal a year.
You end up producing an awful lot of gas.
When you burn coal, you're reacting carbon with oxygen, and the 4 million tonnes of coal they burn here every year becomes, with that added oxygen, about 7 million tonnes of carbon dioxide.
And all of that comes out of these four flues.
ln fact, this one chimney is responsible for a significant proportion of the UK's OO2 emissions.
And that's a big problem, because like it or not, we're going to be relying on coal for our power for many years to come.
But there might just be a way to lessen its impact.
Theoretically, it's possible to extract 90% of the OO2 from the exhaust gases - and that's what's going on in this test facility.
What you're looking at is the start of an experiment which could, at a price, lead to a huge reduction in OO2 emissions from burning coal.
What's going on here is they're literally giving the exhaust gases from the power station a shower.
And it's all to do with chemicals called amines, and they're very good at binding to carbon dioxide.
Nicknamed the Shower in the Tower, as the flue gases rise upwards, a strong amine solution rains down on them.
And incredibly, by the time the exhaust gases have reached the top of that tower, 90% of the carbon dioxide has been absorbed by the tiny amine droplets raining down the inside.
The next stage is to get the carbon dioxide out of the amine solution.
And by warming it .
.
something like that happens.
lt all bubbles out the top.
This is a tiny experimental plant, treating only one six-hundredth of Longannet's gases.
But once they've perfected the technique, they hope to scale it up and ultimately treat every puff of smoke coming from the coal.
- Good bye.
- Bye.
Right, l'm ready.
Seriously guys, why do you think this is a good idea? - Skis made of ice! lt's got to work.
- Good luck, Dallas.
OK Trois, deux, un Geronimo!