Materials: How They Work

This is the vibrant heart of a 21st century city.

There's something strange but wonderful about Piccadilly Circus.

Strange because, as far as the eye can see,

there's nothing natural.

There's not a tree, not a flower, not a blade of grass.

But wonderful because we made it.

We've transformed matter to create the world that we live in.

My name is Mark Miodownik, and as a materials scientist

I've spent my life trying to understand

what's hidden deep beneath the surface

of everything that makes up our modern world.

For me, the story of how materials have driven human civilisation

from the Stone Age to the Silicon Age

is the most exciting story in science.

Without our mastery of the stuff that we found around us,

we would have no buildings, no cars,

no roads, no art.

Nothing.

This is the story of how we created our 21st century world,

how we unlocked the secrets of the raw materials of our planet

and created our future.

First, metals.

From copper and bronze to modern super alloys,

we'll reveal how the atomic structure of metals

gives them their strength.

Next, ceramics. We'll discover the intriguing properties

that have allowed them to shape the modern world.

'From concrete...

'..to fibre optics...' It bends.

'and superconductors.'

The magnet floats on air.

'Finally, plastics.

'We'll explore how scientists trying to improve natural substances,

'like rubber, created a whole new world of modern synthetic materials,

'from Bakelite to graphene.'

This is where our ancestors first settled.

It's where East meets West, where Africa meets Asia.

Underneath my feet, the Earth's crust is shifting.

And the geology here gave our ancestors

access to something that would change their world.

This is one of the first places on Earth

that man stepped out of the Stone Age

and transformed rock into metal.

And it all started with copper.

It's these green streaks that may have been the first clue

there was something a bit special about this rock.

Somehow, we worked out that when you've got this type of rock,

you can do something amazing with it.

We don't really know when our ancestors first discovered

what this marvellous green rock can do.

They might have just ground it up

to use it as a powder to decorate their pottery,

or maybe it happened to be just lying by the fire.

But either way, they discovered something really rather marvellous

about what this stuff can do if you add it to a fire.

Now, the thing about the fire is, you need it to be very, very hot

and for that you need a lot of air,

and that's why they built their fires on hillsides.

These hillsides are extremely windy,

so the air is being funnelled into the fire.

It's actually a genius idea.

And then, when they'd got a very hot fire,

they added the green rock.

And then they kept the temperature high for hours, and they waited.

So when the fire died down,

they would have found bits of a hard stone, black stone,

but amongst that black stone,

look, there's tiny little shiny bits of metal.

They'd transformed rock into metal, it's absolutely extraordinary!

Here we have rock... I mean, there's rock everywhere,

but they'd found the power of transformation.

Look! Look how bright that is! A bright piece of copper.

We know they did it on this hillside because we've found the remnants

from early smelting of our ancestors.

So they did that here,

and this was the beginning of human civilisation,

the age of metals.

Our ancestors realised that with copper,

they could make strong tools,

better than anything they'd had before.

This copper chisel represents the leap out of the Stone Age.

Everything we have in our civilisation today

is due to metal tools like this.

If they get blunt, we can sharpen them.

If they get bent, we can re-straighten them.

If they get damaged, we can repair them.

It's simply the perfect material for tools.

Nothing else our ancestors had in their world

could have done this - not stone, not bone, not wood.

So what's so special about metal?

It's all down to its inner structure.

Metals are made of crystals, and that's a very surprising fact,

because they don't seem to behave

anything like the crystals we are more familiar with.

I'll show you what I mean. I've got a quartz crystal here.

That's what you mean when you say "crystal".

And this is what a quartz crystal says when you hit it with a hammer.

You see? That's what we think of

when we think of crystals being hit with a hammer.

But if I say to you that this piece of metal is made of crystals,

you know already that it's not going to do that.

It's going to be quite malleable, I can do this.

In fact, that's how you work metal, you change its shape.

And that's...that's really strange, because that means

that the crystals in this metal are changing shape instead of exploding.

Inside the metal crystal,

the basic building blocks of everything in the universe, atoms,

are arranged in a regular lattice structure.

But they're not static.

When they're hit, metals can shuffle atoms from one side to the other,

like a Mexican wave.

They can move, rearrange themselves,

and this is why the crystal can change shape.

Metals alone behave like this.

As well as not shattering when you hit them,

they actually get stronger.

The impact creates waves of shuffling atoms

which collide with each other and create blockages.

These make it harder for the atoms to shuffle around,

making the metal stronger.

So the more hammering you do,

the more blockages you form in the crystal,

and so the stronger the metal gets.

It was the strength of metal over stone and wood

that became its main attraction.

With metal tools,

our ancestors could dream up projects on a massive scale.

It's believed the limestone blocks that built the pyramids of Egypt

were carved using copper chisels.

But soon copper wasn't enough.

Our love affair with metals consumed us.

Here on the shores of what's now Israel,

metals from distant lands were traded.

And it was one of these, tin, that moved on the story of metals,

as our ancestors began to mix metals together.

So they took some copper...some tin,

and they melted them together to make a mixture,

which we call an alloy.

And they created a new metal, bronze.

Bronze was the creation of Man the metal-smith,

rather than a gift of nature,

and it gave its name to a new era, the Bronze Age.

Now, this is a nail made out of pure copper,

and as metals go, copper's pretty weak.

Have a look at this.

After a while, it just can't get any further,

and so the metal itself buckles.

If I do the same with a tin nail... let's see what happens.

Tin is actually softer than copper, even.

That's a real joke for a nail, isn't it?

But here's the odd thing.

The mixture, a bronze nail...

well, this is much stronger.

Ha-ha-ha-ha!

So that's odd, isn't it? You add two soft metals together,

and you get something much harder and much stronger.

How do you explain that?

In bronze, the tin atoms replace some of the copper atoms,

which are smaller.

This interferes with the lattice structure,

making it more difficult for the atoms to shuffle across the crystal.

This makes the new alloy much stronger.

The strength of bronze

gave us the means not only to build, but to destroy.

As well as tools,

we made the swords and shields of conquest and dominion.

Bronze propelled the evolution

of a new, complex, more technological society.

It also created new occupations,

such as mining, manufacturing and trading metals.

Since then, we've continued to combine metals,

making new and stronger alloys.

And the most successful combination in history is steel,

an alloy of iron and carbon.

90% of the metal we make today is steel.

It allowed as to travel across the globe by rail...

..by road...

..and by sea.

Strong, reliable steel enabled us to build great cities.

The construction industry would be nowhere without steel.

The buildings around me wouldn't be standing

without steel at their heart.

And we've continued our quest to create better, stronger alloys.

There's been a huge flowering of metallurgy

in the last 60 years.

And there seemed to be no problem we couldn't solve.

'And we were facing another.

'How to get a metal to work in the most extreme environment on Earth.

'A jet engine.'

Let me show you what I mean.

Inside jet engines,

is an incredibly difficult place for metals to be.

Extremely hot temperatures.

Extremely high stress they had to put up with.

So they had to design a new alloy

that could cope with this environment.

And it was called "superalloy".

So-called because it was so super.

Here's a bit of it here.

I'm going to pit it against our old friend steel,

who, of course, we know and love.

I'm going to hang weights off these two wires.

It's the same weight, in both cases,

and they're the same thickness of wire.

So, now they're under the same stress.

Now, I'm going to make it harder for them,

because they'll have to hold that up while under huge temperatures,

which means me putting a blowtorch on them.

OK, are you guys ready? Let's go.

So, the steel wire succumbed within a few seconds.

And that's only a fraction of the heat inside a jet engine.

I could be here all day with the superalloy.

This superalloy can take this.

I know these metals all look the same, but inside this superalloy

is the most exquisite microstructure,

that was designed for this purpose.

To control the movement inside the metal,

and make it unbelievably strong at high temperatures.

'The cubes of material within the superalloy

'are called "gamma prime crystals".

'They sit within the alloy,

'affecting its ability to change shape.

'Which makes it incredibly strong,

'even at temperatures close to its melting point.'

That's pretty impressive,

and, as the jet age progressed,

scientists and engineers pushed the technology,

to create more and more powerful engines.

'Superalloys were the strongest metals

'we had ever created.

But metals alone haven't shaped our modern world.

I'm standing on top of the modern world,

on a structure built from some of the most extraordinary materials that humans have invented.

Everything around me is man-made.

And it's built of this -

sand and clay.

We've transformed sand into transparent glass.

Malleable clay has metamorphosised into hard earthenware

and brittle porcelain.

These miracle materials are ceramics.

All forged from the stuff of the Earth.

And the one I think has had the greatest impact

on the ancient and modern worlds

was invented by the Romans.

Their inspiration may have come from volcanoes,

like Mount Vesuvius and Etna.

When they erupt, they spew out ash and the Romans noticed that,

when the ash got wet, it hardened and became almost as hard as stone.

The Romans saw the potential to make a powerful new material -

concrete.

'Chris Brandon has studied Roman concrete for over 20 years.

'And he's going to help me make some.

'We're using volcanic ash called pozzolana ash

'and adding burnt limestone made into a putty.

'The same ingredients the Romans would have used.'

How do we know that Romans made concrete this way?

Is it written down somewhere, a recipe?

Yes, there is a recipe in Vitruvius, Pliny also wrote about it.

'We're not heating our mixture, but heat is still fundamental'.

The pozzolana ash was formed as minerals reacted

in the extreme heat of a volcano.

And the Romans heated limestone themselves.

As the heat drove off carbon dioxide,

it turns limestone into the very reactive burnt limestone -

quicklime.

'We're adding water right now to make the cement paste.

'That's the key ingredient of concrete.'

We must make sure it is a stiff mix.

You can see this is a paste now,

something I can mould and shape into whatever I want.

The water kicks off a complex set of chemical reactions.

New compounds are formed.

Some are gels which harden into these fibre-like fibrils,

which can be seen magnified many thousand times.

The fibrils grow into a hard, interlocking mesh

that is the basis of concrete's strength.

It's a reaction that can keep going for years,

and the concrete goes on getting harder and harder.

It was concrete that gave the Romans their great structures.

Their amphitheatres, stadiums and the Dome of the Pantheon.

Built almost 2,000 years ago,

spanning a distance of more than 40 metres, the Pantheon still

has the largest unreinforced concrete dome in the world.

But the Romans weren't the only ones to recognise

the huge potential of concrete.

TRAIN WHISTLE BLOWS

Victorians too used it to create magnificent feats of engineering.

But they also realised that it had one fatal flaw.

Dr Phil Purnell has been studying concrete for over 15 years.

Well, today, Mark,

we're going to get you to walk a concrete plank to give us

some indication of how concrete could let us down if not careful.

-Wow, it really is a concrete plank.

-It certainly is, yes.

-We're going to get you to walk across it.

-OK.

So if you would like to sort of get onto that there.

I'm slightly nervous about this, because I can't

imagine that there is a good reason for me walking a plank.

As you gently inch your weight across the plank,

you're making it bend, you're bending the concrete.

And when you bend something, the top of that goes into crushing,

it's being crushed, it goes into compression.

The bottom of it is pulled apart and goes into what we call tension.

'As the plank curves a tiny bit under my weight,

'the top surface becomes concave and is squashed,

'while the bottom is stretched.'

Of course, as I get closer to the middle,

I'm making the plank work much harder.

When you're in the middle, you have

a maximum crushing on the top and a maximum pulling underneath.

-Concrete is very, very good...

-CRASH!

..but as you can see, very, very poor in tension.

-So what we've demonstrated...

-That's exactly what you don't want a building to do!

-Exactly.

-You really don't want that to happen.

-OK, wow.

This is actually a thick piece of concrete, I'm really surprised.

That's as thick as your concrete floors at home or an office block.

-That's a genuine thickness of concrete.

-Wow.

'The reason concrete can snap like this is down to its inner structure.'

Concrete isn't entirely solid. It's riddled with tiny holes.

When it's compressed, the holes close up

and the concrete stays strong.

But when it's under tension, the holes open up.

Stress will concentrate at the edges of the holes.

Here, cracks can start...

..and the stress can be powerful enough to split the concrete.

As the cracks grow, they join up with other cracks

and can rip the concrete apart.

So, to build bigger, we would need to find a way

of working around concrete's one great weakness.

So, what is this trick? What's the answer to making concrete stronger,

resisting these bending forces?

Well, back in the 1850s, there was a plasterer from Newcastle,

called Mr Wilkinson, and he was making concrete floor slabs.

And what he noticed is that these slabs have a tendency

to crack in between the joists.

Just like my unfortunate experience with the plank.

Exactly like your unfortunate experience with the plank, yes.

So Wilkinson noticed where the cracks were appearing

in his concrete floor slabs and he had an idea, and a very bright idea.

And he took some barrel hoops,

took some of the flat hoops that go around and hold a barrel together,

and he placed them in the concrete where he noticed the cracks

were appearing, where he knew we had to resist these pulling forces.

-So he invented reinforced concrete?

-He did. Back in 1853. Yes.

-What a dude.

-Absolutely! He laid the foundations for modern urban life.

Without reinforced concrete, nothing we see around us would exist.

Reinforced concrete might seem simple,

but it works because steel is the perfect partner for concrete.

They both share a surprising quality.

They expand and contract at the same rate when they get hot or cold.

And unlike concrete, steel is strong when it's under tension.

It bends without breaking, like concrete does.

As we learned more about materials,

we found it easier to find clever ways to fix problems.

For instance, we didn't try to stop concrete cracking completely,

just to control it.

So, to test this beam, we're pushing down on it repeatedly

with a force of about 2.5 tonnes, so we are putting it under the sort

of loads that we might expect, for example, a rail or road bridge

to be put under when large vehicles go over the top of it.

I can see it's bending. It's bending quite a lot.

It's bending quite a lot, yes.

I hate to tell you this, but it's cracking.

It's cracking quite considerably.

But look at the difference compared to our plank in the other room.

Here, our cracks are only travelling a certain way up,

because what is happening is, the steel is holding the beam together,

the steel is holding that crack together.

If I just traced this crack out, to highlight it a bit more clearly.

We can see the crack is travelling up from the bottom of the beam.

But it stops roughly halfway up the beam,

so I will just raw a dotted line there to show where it stopped.

And everything above that dotted line is

going into the crushing force, into compression.

Everything below that dotted line is being pulled, going into tension.

So above the line, the concrete is doing the work.

Below the line, the steel is doing the work.

So we're getting the very best out of both materials.

-So that crack is stable? Nothing to worry about?

-It's perfectly stable.

All reinforced concrete buildings are cracked to some degree,

and the important thing, when designing reinforced concrete,

is to make sure that you have lots and lots

and lots of small cracks instead of one very, very big crack.

Most people see concrete as drab, grey and ugly.

It hasn't got many fans.

But I think it's an extraordinary material.

You can build man-made mountains with it.

Buildings of any shape you want.

Structures that will last for thousands of years.

And that's the secret of concrete's success.

Many of the iconic structures of our era, the Sydney Opera House,

the Millau Viaduct, the tallest bridge in the world,

and Dubai's Burj Khalifa, the world's tallest building,

wouldn't exist without reinforced concrete.

Reinforced concrete is flexible and versatile and it's freed us

from the limitations of stone and brick.

In the age of concrete, the only limitation is our imagination.

Ceramics are now shaping society in ways that are more profound

than the buildings we live in.

We've discovered that, at the very small-scale,

and at extreme temperatures,

these materials behave in ways that we just hadn't imagined.

And that's propelled us into the information age.

'It's a story that didn't begin in a high-tech lab,

'but in the dentist's chair.' At the beginning of the 20th century,

inventors realised that bent quartz rods could carry light.

And so they created the dental illuminator.

'Then, a German medical student took the idea further.

'He assembled lots of thin fibres into bundles

'to see if he could transmit not just light, but an image.'

His goal was to look at the inaccessible parts of the body during surgery.

'And fibre-optic bundles were perfect.

'They could follow the contours of the body,

'because of a surprising property of glass.'

Glass of the everyday scale is brittle and stiff,

but at the microscale, it behaves totally differently.

It bends.

You can only see this amazing elastic property of glass

in something as thin as an optical fibre,

the diameter of a human hair.

Atoms in glass are connected by bonds,

which behave a little like stiff springs.

This means glass can bend a tiny bit.

The finer the glass thread, the less force it needs to bend.

So the less likely it is to crack.

And in such a fine thread, drawn from molten glass,

there's less chance of a defect, which could make it shatter.

That's not the only thing that's special about this glass.

It's also incredibly pure, so light can travel down it for miles.

But light normally travels in straight lines,

so how does it go around these bends?

'To find out, I'm with Dr Natalie Wheeler,

'who researches optical fibres at the University of Southampton.'

So here we have a length of optical fibre, and as you can see,

it's extremely thin, and also, since it's been coated with

a polymer during the fabrication process, it's also extremely strong.

Inside the coating of this optical fibre is a glass core,

surrounded by a glass cladding layer.

It's these two layers that help the light go around bends.

We can actually demonstrate how this works using this set up here.

-If you would like to just pull out that cork there.

-This one?

-Yeah.

Wow! That's amazing! Look at that!

'This laser light mimics what happens in an optical fibre.

'When light travels from a dense to a less dense medium,

'like this liquid to air,

'or from the glass core to its cladding layer,

'what happens to the light depends on the angle at which it hits the boundary.

'If the angle is large enough, it won't pass through.

'It'll be reflected back in.'

At the interface between the two materials,

the light is being reflected, and you can see it bouncing along here.

So the interface between them allows the total internal reflection?

-Exactly.

-That's absolutely fantastic.

Using these amazing properties of optical fibres, in 1930,

medical student, Heinrich Lamm, successfully transmitted

the first image of a lightbulb filament using an optical fibre bundle.

Then scientists realised they could have a far more powerful use -

to transmit vast amounts of information at the speed of light.

Optical fibres have become a foundation

of the information revolution.

Without them, we wouldn't have our world of instant phone calls,

e-mails, cable TV or the internet.

Today, a single strand of optical fibre can transmit

2.5 million times more information than a standard copper cable.

In fact, over the last 50 years,

ceramics have been taking over from metals

in a materials revolution that gave us our high-tech, high speed world.

Ceramics have also been replacing metals

in medicine and in electronics.

But there's one essential of life that surely metals are vital for -

electricity.

Electricity travels down miles and miles of metal wires to reach us.

And because of the way metals conduct,

some of the energy is lost along the way.

If I make a small electric circuit with some copper wire,

a battery and a bulb, the bulb burns

pretty brightly, but now, if I just use a longer wire,

65 metres of it, same bulb, same battery,

it's much duller.

So the wire absorbs quite a lot of the electricity.

So when it comes to crossing countries and continents,

we lose a massive amount of energy.

The UK's electricity network loses more than 7% of the electricity

just getting from the power station to your plug.

But that could change and it's all down to the way

some materials respond to extreme temperatures.

This time, the transformation isn't due to the power of heat,

but of cold.

In 1911, Dutch physicist Heike Kamerlingh Onnes

was testing materials at extremely low temperatures.

He cooled mercury down to the temperature of liquid helium.

Minus 269 degrees Celsius.

That's just four degrees above absolute zero.

Onnes discovered something that nobody had ever seen before.

At these extreme temperatures,

mercury conducts electricity without losing any energy at all.

He called it superconductivity.

In a metal, electricity is conducted when electrons travel through it.

At normal temperatures,

the electrons bump into atoms and lose energy.

It's called electrical resistance.

But at extremely low temperatures, the electrons can pair up and

navigate through the atoms without bumping into them and losing energy.

The metal now has no electrical resistance.

Onnes received a Nobel Prize for his work.

And in the years that followed, scientists discovered

that many other metals become superconductors at temperatures close to absolute zero.

With society depending more and more on electricity,

superconductors seem to have a huge potential.

But the breakthrough was as frustrating as it was exciting.

How could we find a use for something that only worked at such extreme temperatures?

What was needed was a material that would perform like the superconducting metals,

but at a temperature that wasn't down near absolute zero.

And when the breakthrough came, it wasn't the material

that anyone expected to conduct electricity at all.

It wasn't a metal. It was a ceramic.

This is a ceramic called yttrium barium copper oxide,

and not only does it not conduct electricity, it doesn't

really behave very interestingly at all to electricity or magnets.

It seems dead. But cold does many strange things to this material.

If we cool it down

and, admittedly, we have to cool it down quite a lot,

to liquid nitrogen temperatures, that's minus 196 degrees centigrade.

It takes a few minutes for the liquid nitrogen to cool it right down,

and when it does, the ceramic becomes a superconductor.

And it has another trick up its sleeve.

Now when I place a magnet over the ceramic,

something completely different happens.

It seems like the magnet floats on air.

What's happening is it is being levitated by the ceramic.

The ceramic is repelling the magnetic field of the magnet.

It's absolutely extraordinary.

The cold has changed the way the ceramic behaves.

It's showing another material miracle

that's unique to superconductors.

Normally, this ceramic isn't affected at all by a magnet.

But when the ceramic is cooled, and becomes a superconductor,

an external magnetic field makes electrical currents flow within it.

These generate their own magnetic field

which repels the external one.

And so a ceramic can repel a magnet.

This ceramic has now become a superconductor and that means

it can conduct electricity without losing any energy.

It can do that when it's cooled to about minus 196 degrees centigrade.

That may sound extreme, but it's pretty warm compared

to the temperatures you need to make metals superconduct.

Since they discovered this,

scientists have begun to design ceramics at the atomic level.

They've added different elements, atom by atom,

in search of their ultimate aim.

Superconductors that will work at practical temperatures.

Degree by degree, we're approaching our goal.

We currently use this thick copper cable to transmit electricity.

But it can now be replaced by this thin superconducting ceramic cable.

And as long as it's cooled, it will lose no electricity.

In America, ceramic superconductors

have started to be used in the power grid.

China and Korea are planning to use them in cities of the future.

In years to come, they could transport electricity on a massive scale.

Just imagine, solar farms in the desert could be supplying

our homes in Britain with minimal energy being lost on the way.

By pushing metals and ceramics to their very limits,

we've built vast cities that have changed the face of the planet.

We've conquered land, sea and air.

And we've learnt to communicate at the speed of light.

But I think the materials that are perhaps our greatest achievement

are something entirely artificial, invented by us,

and created in the lab -

plastics.

It's not just technologically marvellous stuff.

It's fundamentally changed how we live.

It's allowed us to be modern.

I'm going to explore how we turned our backs

on the raw materials of nature and began to design and create our own.

Plastic - better, cheaper, and entirely man-made.

We've created more new materials in the last 100 years

than in the rest of history, and what's really exciting about that

is that it's just the beginning.

We're on the verge of creating a new generation of materials

more ambitious than ever before.

And that's because we are coming full circle

and making new materials that are completely artificial,

but which take their inspiration from the natural world.

The story began in 1834, in a prison in Philadelphia

with one inmate who saw the potential

of a newly imported natural material.

His name was Charles Goodyear,

and he'd been locked up for not paying his debts.

But Goodyear wasn't making his supper,

he was cooking up something entirely different.

Goodyear was obsessed with this stuff, natural rubber.

It was the miracle substance of the early 19th century

because it had some very strange properties.

It was stretchy but it was also waterproof.

And this meant that it seemed to have huge potential to make things

like raincoats, tyres and wellies.

If, however, it wasn't for one thing.

This is a ball of natural rubber...

..and you can see that at room temperature

it's pretty lively stuff.

But if you change the temperature,

well then, the material changes its behaviour.

So look, I've got some different types of temperature here.

I've got a ball that's been cooled down.

And here it is.

And let's see how that behaves.

It's quite ridiculously dead, inert.

None of that springiness. None of that liveliness is left.

And what about the hot one?

It's funny, you only have to heat it up a little bit

and it becomes really pongy and also sticky.

Almost disgusting. It's a very unpleasant material to be around.

In Goodyear's day, people noticed this

and products made out of natural rubber

were pretty hopeless in the hot or the cold weather.

Shops that sold them, well, they were inundated with complaints.

So this is the problem that Goodyear was trying to solve.

Goodyear was determined to find the magic ingredients

that would improve rubber and transform it into a material

that didn't melt in the heat or go hard in the cold.

He tried mixing rubber with the most bizarre substances imaginable,

from black ink to witch hazel to chicken soup!

But nothing seemed to work.

But his luck was to change.

In 1839, having been bailed out of debtor's prison,

Goodyear found himself at a small rubber company in Massachusetts.

Dr Stuart Cook is director of research

at the Malaysian Rubber Board's UK research centre

and is going to help us recreate what Goodyear did.

That counts as one of the weirdest things I've ever seen.

Goodyear was still trying anything he could lay his hands on.

And this time,

he tried adding two substances to the natural rubber,

yellow sulphur and white lead,

which was commonly used as a pigment.

Using the factory's mill, these were ground into the natural rubber

until they were both thoroughly mixed in.

So you can see now the rubber compound

has changed quite dramatically.

Yes. It's looking extremely voluptuous, actually.

-It's got this creaminess about it.

-Yes.

So far, there were no signs that Goodyear was any closer

to reaching his goal of improving on natural rubber.

The rubber compound that came out of the mill

appeared no better than previous attempts.

Stuart, I have to say it is sticky.

I mean, he must have been pretty disappointed

because he's trying to solve the stickiness problem, and it's sticky.

The crucial thing is what happened next.

Whether by mistake or not,

Goodyear left the rubber compound lying on a hot stove.

Natural rubber would have melted into a gooey mess,

but Goodyear's rubber compound didn't do this.

The combination of sulphur, white lead and heat

had transformed the rubber into a very different material.

That is absolutely extraordinary. What an amazing material.

So Goodyear, when he referred to this,

said it had the appearance of looking charred.

It's better than charred, I think he was under-estimating that!

And it's not sticky.

Cured, as Goodyear said.

This is what the surface of natural rubber looks like

magnified over 10,000 times.

It's an irregular structure with stretched-out fibres

interspersed with tiny air pockets.

By a process which became known as vulcanisation,

Goodyear had transformed this to make it useful to man.

The key to that change is what happens inside the rubber.

Natural rubber is made up of lots of long strands.

Each one, a single molecule made of atoms.

During vulcanisation, the sulphur creates links between the molecules.

This is what makes rubber tougher

and able to withstand hot or cold temperatures.

So he must have been a very happy man?

I think he realised the importance of this chance discovery.

But it took him then many years to convince the rest of the world.

But this was really the start of the rubber industry as we know it.

The significance of Goodyear's discovery went far beyond rubber.

What he showed was the power of chemistry

to transform raw materials into something new.

What he'd discovered was still called rubber

but it didn't occur naturally.

It was man-made.

The success of rubber kick-started a quest for more man-made materials

to better nature's own.

This led to the discovery of the first commercially-produced plastic.

And no-one was more aware of its potential than Dr Leo Baekeland.

In his mansion in the suburbs of New York, he set to work.

He'd set his sights on replacing shellac

which is the material that old records were made out of.

Shellac is a resin that's excreted by the Indian lac beetle,

and it looks like this!

And as the demand for shellac increased,

the lac beetle just couldn't keep up.

And Baekeland thought that he could solve this problem

by creating a new plastic.

In the grounds of his estate, Baekeland had built a chemistry lab

equipped with everything he would need.

Baekeland's starting point

was to investigate a mysterious chemical reaction.

It involves mixing two chemicals, phenol and formaldehyde.

Dr Sara Ronca is a chemist at Loughborough University

and is an expert in plastics.

This is quite a pongy reaction you've got here.

It's a very smelly one!

This is the reaction that interested Baekeland.

It takes a few minutes before anything happens...

He must have been a patient man, Baekeland?

You really need a lot of patience.

..but then, something rather spectacular occurs.

-Oh! Woah.

-Yeah.

The reaction creates a plastic-y substance

that moulds to the shape of the beaker,

and turns pink.

Nobody had yet found a use for it.

But it caught the attention of Baekeland.

Look it, though. It's pretty cool stuff!

It does look promising, I can see why he's interested in it.

It's sort of plasticy, but it falls apart.

It falls apart and it's porous, so you cannot really use it.

Baekeland understood that if he managed to get

a better version of this material, this could have some potential.

Baekeland believed he could find a way

to modify the chemical reaction

so it would give him a better, stronger, more useful plastic.

Day after day, he tried everything he could think of.

After five years of painstaking work,

he finally found that by controlling the speed of the reaction

with chemicals and heat, he could produce something different and new.

This time, there was no pink solid produced.

Instead, inside the flask an orange resin was slowly forming.

Let's have a look. It looks...

It's like honey.

It's very very viscous. Exactly like honey.

Baekeland's next step was to pour the liquid resin into a mould.

With pressure and heat,

he hoped it would turn into a solid plastic shape.

In our case, we're trying to make a plastic cup.

So either this is going to be a soggy mess or...

Let's see what we managed to achieve.

Oh. Aw.

Well, I don't think this is quite what we were expecting to produce!

What do you think went wrong?

I guess we didn't wait long enough.

We still have some bubbles in it.

But you can see the shape.

Can you imagine how many times Baekeland had to repeat this

to get something nice?

I think for me, you see modern plastic objects

in their perfect thousands, millions of them.

When you actually try to make one yourself,

you realise it's really tricky stuff.

Baekeland persisted

until he had perfected the process to make hard, solid plastic objects.

And he named his new plastic Bakelite.

As a liquid resin, Bakelite is made up of stringy chains

that can move around, so it can be moulded.

But when heat and pressure are applied,

the chains grow in length, links form between them,

locking Bakelite into shape.

Bakelite was a major breakthrough.

By the end of 1930s, over 200,000 tonnes of Bakelite

had been made into a fantastic variety of household objects.

But as successful as it was, even Bakelite had its limits.

What strikes you is not just what's here, but what's missing.

There are no plastic bags, there are no water bottles,

there are no trainers,

these objects that form such a large part of our lives.

And that's because Bakelite is just not up to making those things.

It's too hard and brittle. It's inflexible.

This material of a thousand uses,

never became as ubiquitous as the plastics we use today.

But that was about to change.

Factories would soon be churning out countless new plastics

that would transform our lives.

They weren't invented by chance or trial and error,

but for the first time

through an understanding of the inner structure of plastics.

Plastics are polymers and that's Greek for many parts.

So they're a bit like this chain of paperclips.

They're individual components linked together.

Although in the case of plastics, the individual components

are molecules containing mostly carbon and hydrogen.

And the key thing is that they can join together to form long chains.

Now in the 1920s, when scientists realised

this is what plastics looked like,

it opened up new possibilities for making plastics.

Because before then, well,

the chemical reactions they were using were a bit of a mystery.

But then they realised that they only had to find molecules

that would link together

and they could create loads of new plastics.

And in one of those great moments in history

where knowledge and opportunity coincide,

scientists realised that a vast source of raw ingredients

for these new plastics had already been discovered.

With the proliferation of the motorcar

and expansion of industry and cities,

enormous quantities of oil and gas were being pumped out of the ground

and processed into fuel.

And the products of oil and gas refineries

were hydrocarbons, containing exactly the kind of molecules

that could join up to make plastics.

Cheap and abundant,

everything was now in place for the plastics explosion.

Nylon, PVC,

polystyrene, polyester.

All destined to become household names.

Plastics were taking over our material world.

Everything from toys and tools to footwear and furniture

could now be made with plastics.

In every aspect of our lives,

they were replacing more traditional materials

like metals and woods, ceramics and leather.

But there was one area which they couldn't compete,

and that's where strength was required.

The modern age demanded strong materials.

And when we needed strength,

we looked not to plastics but to metals.

On their own, plastics were too weak,

too bendy to make a car or a plane.

But plastics had one big advantage, they were light,

an essential quality for speed and flight.

So scientists set out on a quest to create plastics as strong as metals.

In 1963, engineers at the Royal Aircraft Establishment

in Farnborough made a breakthrough.

They managed to strengthen plastic so effectively,

it looked as though it might give metal a run for its money.

This is carbon fibre.

It's extremely strong, light and stiff.

Scientists found that when they combined it with plastic

they created a new material that was much better

than the sum of its parts.

Some people called it black plastic,

but today we know it as carbon fibre composite.

Here, a carbon fibre composite is being made from sheets

that contain carbon fibres and plastic.

It's built up layer by layer,

on moulds that can take any shape you need.

And then cooked in an oven, to make the plastic set hard.

The end result is a material with a unique combination of properties,

strong, stiff and light.

Ideal for making one of the fastest machines on the planet.

Since the 1980s,

Formula One teams stopped using metal for their car bodies,

and changed to using carbon fibre composite

because of its winning combination

of lightness, stiffness and strength.

But lightness, stiffness and strength

aren't all we demand from our materials.

In recent years, one new material with exotic

but incredibly useful properties has come out of the lab -

graphene.

It's the strongest material we know.

200 times stronger than steel.

And in this two-dimensional material,

electricity travels at an amazing one million metres per second.

The different colours represent different thicknesses of graphite.

The yellow is hundreds of atoms thick.

But the fragment that is faint blue, almost transparent,

is just one single atomic layer.

You can't go thinner than this.

This is who I've come to see.

Professor Andre Geim is one-half of the Nobel Prize-winning duo

that discovered graphene.

Because it shows so remarkable properties, especially conductivity.

Think about this. This is only atom thick.

And when you make films thinner and thinner,

usually properties deteriorate.

In this, you are at the ultimate limit.

Magnified 20 million times,

this is what graphene looks like at the atomic scale.

Each blurry white spot is an individual carbon atom

and you can just make out how they are arranged in a hexagonal pattern.

Graphene is two dimensional

and that's what gives it its unique properties.

This material, despite being one atom thick,

it's already conducting and that was sort of eureka moment

when I first realised that this material is worth studying.

In the hi-tech, dust-free clean labs at Manchester,

Andre's team are developing transistors made from graphene.

Graphene could ultimately replace silicon chips,

creating the next generation of super-fast computers,

up to 100 times faster than today's.

And we're only just beginning to imagine the vast possibilities

graphene opens up in other fields of science.

There's a sense in which anything is possible,

that only our imaginations will limit what we can create.

We've come a long way since we smelted copper

from the rocks of the desert.

We've manipulated, moulded and manufactured materials

that have allowed us to shape our modern world

and create magnificent structures like these.

But for me, there's no doubt that the journey is far from over.

There are new discoveries to be made,

frontiers to be crossed.

The inner world of material science holds much of the key to our future.