Original subtitles

On the 14th of August 1894,

an excited crowd gathered

outside Oxford's Natural History Museum.

This huge Gothic building was hosting the annual meeting

of the British Association for the Advancement of Science.

Over 2,000 tickets had been sold in advance,

and the museum was already packed,

waiting for the next talk to be given

by Professor Oliver Lodge.

His name might not be familiar to us now,

but his discoveries should have made him as famous

as some of the other great electrical pioneers of history,

people like Benjamin Franklin,

Alessandro Volta,

or even the great Michael Faraday.

Quite unwittingly, he would set in motion

a series of events that would revolutionize

the Victorian world of brass and telegraph wire.

This lecture would mark the birth

of the modern electrical world,

a world dominated by silicon

and mass wireless communication.

In this program, we discover how electricity

connected the world together

through broadcasting and computer networks,

and how we finally learnt to unravel and exploit electricity

at an atomic level.

After centuries of man's experiments with electricity,

a new age of real understanding was now dawning.

These tubes are not plugged in to any power source,

but they still light up.

It's electricity's invisible effect,

an effect not just confined to the wires it flows through.

In the middle of the 19th century,

a great theory was proposed to explain how this could be.

The theory says that surrounding any electric charge,

and there's a lot of electricity flowing above my head,

is a force field.

These florescent tubes are lit

purely because they are under the influence

of the force field from the power cables above.

The theory that a flow of electricity could, in some way,

create an invisible force field,

was originally proposed by Michael Faraday,

but it would take a brilliant young Scotsman

called James Clerk Maxwell, who would prove Faraday correct.

And not through experimentation, but through mathematics.

This was all a far cry from the typical 19th century way

of understanding how the world works,

which was essentially to see it as a physical machine.

Before Maxwell, scientists had often built strange machines

or devised wondrous experiments

to create and measure electricity.

But Maxwell was different.

He was interested in the numbers,

and his new theory not only revealed

electricity's invisible force field,

but how it could be manipulated.

It would prove to be one of the most important

scientific discoveries of all time.

Maxwell was a mathematician, and a great one

and he saw electricity and magnetism in an entirely new way.

He expressed it all

in terms of very compact mathematical equations.

And the most important thing is that in Maxwell's equations

is an understanding of electricity and magnetism

as something linked

and as something that can occur in waves.

Maxwell's calculations showed

how these fields could be disturbed

rather like touching the surface of water with your finger.

Changing the direction of the electric current

would create a ripple or wave

through these electric and magnetic fields.

And constantly changing the direction

of the flow of the current forwards and backwards,

like an alternating current,

would produce a whole series of waves,

waves that would carry energy.

Maxwell's maths was telling him

that changing electric currents

would be constantly sending out great waves of energy

into their surroundings,

waves that would carry on forever

unless something absorbed them.

Maxwell's maths was so advanced and complicated

that only a handful of people understood it at the time,

and although his work was still only a theory,

it inspired a young German physicist called Heinrich Hertz.

Hertz decided to dedicate himself to designing an experiment

to prove that Maxwell's waves really existed.

And here it is.

This is Hertz's original apparatus

and its beauty is in its sheer simplicity.

Heat generates and alternating current

that runs along these metal rods,

with a spark that jumps across the gap

between these two spheres.

Now, if Maxwell was right,

then this alternating current should generate

an invisible electromagnetic wave

that spreads out into the surroundings.

If you place a wire in the path of that wave,

then at the wire,

there should be a changing electromagnetic field,

which should induce an electric current in the wire.

So what Hertz did was build this ring of wire, his receiver,

that he could carry around

in different positions in the room

to see if he could detect the presence of the wave.

And the way he did that

was leave a very tiny gap in the wire,

across which a spark would jump

if a current runs through the ring.

Now, because the current is so weak

that spark is very, very faint

and Hertz spent pretty much most of 1887

in a darkened room, staring intensely through a lens

to see if he could detect the presence of this faint spark.

But Hertz wasn't alone in trying to create Maxwell's waves.

Back in England,

a young physics professor called Oliver Lodge

had been fascinated by the topic for years

but hadn't had the time to design any experiments

to try to discover them.

Then one day in early 1888,

while setting up an experiment on lightning protection,

he noticed something unusual.

Lodge noticed that when he set up his equipment

and sent an alternating current around the wires,

he could see glowing patches between the wires,

and with a bit of tweaking,

he saw these glowing patches formed a pattern.

The blue glow and electrical sparks occurred

in distinct patches, evenly spaced along the wires.

He realized they were the peaks and troughs of a wave,

an invisible electromagnetic wave.

Lodge had proved that Maxwell was right.

Finally, by accident, Lodge had created.

Maxwell's electromagnetic waves around the wires.

The big question had been answered.

Filled with excitement at his discovery,

Lodge prepared to announce it to the world,

at that summer's annual scientific meeting

run by the British Association.

Before it though, he decided to go on holiday.

His timing couldn't have been worse,

because back in Germany, and at exactly the same time,

Heinrich Hertz was also testing Maxwell's theories.

Eventually, Hertz found what he was looking for:

A minute spark.

And as he carried his receiver around

to different positions in the room,

he was able to map out the shape

of the waves being produced by his apparatus.

And he checked each of Maxwell's calculations carefully

and tested them experimentally.

It was a tour de force of experimental science.

Back in Britain,

as the crowds gathered for the British Association meeting,

Oliver Lodge returned from holiday

relaxed and full of anticipation.

This, Lodge thought, would be his moment of triumph,

when he could announce his discovery of Maxwell's waves.

His great friend, the mathematician Fitzgerald,

was due to give the opening address in the meeting.

But in it, he proclaimed that Heinrich Hertz

had just published astounding results:

He had detected Maxwell's waves traveling through space.

We have snatched the thunderbolt from Jove himself

and enslaved the all-pervading ether, he announced.

Well, I can only imagine how Lodge must have felt

having his thunder stolen.

Professor Oliver Lodge had lost his moment of triumph,

pipped at the post by Heinrich Hertz.

Hertz's spectacular demonstration

of electromagnetic waves, what we now call radio waves,

even though he didn't know it at the time,

is gonna lead to a whole revolution in communications

over the next century.

Maxwell's theory had shown how electric charges

could create a force field around them,

and that waves could spread through these fields

like ripples on a pond,

and Hertz had built a device

that could actually create and detect the waves

as they passed through the air.

But almost immediately, there would be another revelation

in our understanding of electricity,

A revelation that would once again involve.

Professor Oliver Lodge,

and once again, his thunder would be stolen.

The story starts in Oxford, in the summer of 1894.

Hertz had died suddenly earlier that year,

and so Lodge prepared a memorial lecture

with a demonstration that would bring the idea of waves

to a wider audience.

Lodge had worked on his lecture,

he'd researched better ways of detecting the waves,

and he'd borrowed new apparatus from friends.

He'd made some significant advances

in the technology designed to detect the waves.

This bit of apparatus generates an alternating current

and a spark across this gap.

The alternating current sends out an electromagnetic wave,

just as Maxwell predicted,

that is picked up by the receiver.

It sets off a very weak electric current

through these two antennae.

Now, this is what Hertz had done.

Lodge's improvement on this

was to set up this tube full of iron fillings.

The weak electric current passes through the filings,

forcing them to clump together.

And when they do, they close a second electric circuit

and set off the bell.

So if I push the button on this end,

It sets off the bell at the receiver.

And it's doing that with no connections between the two,

it's like magic.

You could imagine a packed house,

lots of people in the audience,

and what they suddenly see is,

as if by magic, a bell ringing.

It's quite incredible.

It might not have been

the most dramatic demonstration the audience had ever seen,

but it certainly still created a sensation among the crowd.

Lodge's apparatus, laid out like this,

no longer looked like a scientific experiment.

In fact, it looked remarkably like those telegraph machines

that had revolutionized communication,

but without those long cables

stretching between the sending and receiving stations.

To the more worldly and savvy members of the audience,

this was clearly more

than showing the maestro Maxwell was right,

this was a revolutionary new form of communication.

Lodge published his lecture notes

on how electromagnetic waves could be sent and received

using his new improvements.

All around the world,

inventors, amateur enthusiasts, and scientists

read Lodge's reports with excitement

and began experimenting with Hertzian waves.

Two utterly different characters were to be inspired by it.

Both would bring improvements to the wireless telegraph,

and both will be remembered

for their contribution to science

far more than Oliver Lodge.

The first was Guglielmo Marconi.

Marconi was a very intelligent, astute,

and a very charming individual,

he definitely had the Italian-Irish charm,

He could apply this to almost anyone

from young ladies to world-renowned scientists.

Marconi was no scientist,

but he read all he could of other people's work

in order to put together his own wireless telegraph system.

It's possible that because he was brought up in Bologna

and it was fairly close to the Italian coast,

that he saw the potential of wireless communications

in relation to maritime usage fairly early on.

Then, aged only 22, he came to London

with his Irish mother to market it.

The other person inspired by Lodge's lecture

was a teacher at the Presidency College in Calcutta,

called Jagadish Chandra Bose.

Despite degrees from London and Cambridge,

the appointment of an Indian as a scientist in Calcutta

had been a battle against racial prejudice.

Indians, it was said,

didn't have the requisite temperament for exact science.

Well, Bose was determined to prove this wrong,

and here in the archives,

we can see just how fast he set to work.

This is a report

of the 66th meeting of the British Association

in Liverpool, September 1896.

And here is Bose,

the first Indian ever to present at the Association meeting,

talking about his work and demonstrating his apparatus.

He'd built and improved-on

the detector that Lodge described,

because in the hot, sticky Indian climate,

he'd found that the metal filings inside the tube

that Lodge used to detect the waves

became rusty, and stuck together,

so Bose had to build a more practical detector

using a coiled wire instead.

His work was described as a sensation.

The detector was extremely reliable

and could work on board ships,

so had great potential for the vast British naval fleet.

Britain was the center

of a vast telecommunications network

which stretched almost around the world,

which was used to support an equally vast maritime network

of merchant and naval vessels,

which were used to support the British Empire.

But Bose, a pure scientist, wasn't interested

in the commercial potential of wireless signals,

unlike Marconi.

This was sort of a new, cutting-edge field,

but Marconi wasn't a trained scientist,

so he did come at things in a fairly different way,

which may have been why he progressed so quickly

in the first place.

And he was very good at forming connections

with the people he needed to form connections with,

to enable his work to be done.

Marconi used his connections

to go straight to the only place

that had the resources to help him.

The British Post Office was a hugely powerful institution.

When Marconi first arrived in London in 1896,

these buildings were newly completed

and already heaving with business

from the empire's postal and telegraphy services.

Marconi had brought his telegraph system

with him from Italy,

claiming it could send wireless signals

over unheard-of distances,

and the Post Office Engineer-in-Chief, William Preece,

immediately saw the technology's potential.

So Preece offered Marconi

the great financial and engineering resources

of the Post Office, and they started work up on the roof.

The old headquarters of the Post Office were right there.

And between this roof and that one,

Marconi and the Post Office engineers

would practice sending and receiving electromagnetic waves.

The engineers helped him improve his apparatus,

and then Preece and Marconi together demonstrated it

to influential people in Government and the Navy.

What Preece didn't realize

was that even as he was proudly announcing.

Marconi's successful partnership with the Post Office,

Marconi was making plans behind the scenes.

He'd applied for a British patent

on the whole field of wireless telegraphy

and was planning on setting up his own company.

When the patent was granted,

all hell broke loose in the scientific community.

That patent was itself revolutionary.

You see, patents could only be taken out on things

that weren't public knowledge,

but Marconi famously had hidden his equipment

in a secret box.

And here it is.

When his patent was finally granted,

Marconi ceremoniously opened the box,

everyone was keen to see what inventions lay within.

Batteries forming a circuit,

iron filings in the tube to complete the circuit

to ring the bell on top.

Nothing they hadn't seen before,

and yet Marconi had patented the lot.

The reason Marconi is famous

is not because of that invention.

He doesn't invent radio, but he improves it,

and turns it into a system.

Lodge doesn't do that, and that's why we remember Marconi,

and that's why we don't remember Lodge.

The scientific world was up in arms.

Here was this young man who knew very little

about the science behind his equipment,

about to make his fortune, from their work.

Even his great supporter Preece was disappointed and hurt

when he found out Marconi was about to go it alone

and set up his own company.

Lodge and other scientists began a frenzy

of patenting every tiny detail and improvement

they made to their equipment.

This new atmosphere shocked Bose

when he returned to Britain.

Bose wrote home to India

in disgust at what he found in England.

Money, money, money all the time, what a devouring greed.

I wish you could see the craze for money of the people here.

His disillusionment with the changes he saw

in the country he revered

for scientific integrity and excellence, is palpable.

Eventually though, it was his friends

who convinced Bose to take out his one and only patent,

on his discovery of a new kind of detector for waves.

It was this discovery that would lead

to perhaps an even greater revolution for the world:

He had discovered the power of crystals.

This replaces older techniques using iron filings,

which are messy, and difficult, and don't work well,

and here's a whole new way of detecting radio waves,

and it's one that's going to be at the center

of a radio industry.

Bose's discovery was simple,

but it would truly shape the modern world.

When some crystals are touched with metal

to test their electrical conductivity,

they can show rather odd and varied behavior.

Take this crystal, for example.

If I can touch it in exactly the right spot

with the tip of this metal wire,

and then hook it up to a battery,

it gives quite a significant current.

But if I switch round my connections to the battery

and try and pass the current through

in the opposite direction, it's a lot less.

It's not a full conductor of electricity,

it's a semiconductor,

and it found its first use

in detecting electromagnetic waves.

When Bose used a crystal like this in his circuits

instead of the tube of filings,

he found it was a much more efficient and effective

detector of electromagnetic waves.

It was this strange property

of the junction between the wire,

known as the cat's whisker,

and the crystal, which allowed current to pass

much more easily in one direction than the other,

that meant it could be used

to extract a signal from electromagnetic waves.

At the time, no-one had any idea

why certain crystals acted in this way,

but to scientists and engineers, this strange behavior

had a profound and almost miraculous practical effect.

With crystals as detectors,

now it was possible to broadcast

and detect the actual sound of a human voice, or music.

In his Oxford lecture in 1894,

Oliver Lodge had opened a Pandora's box.

As an academic, he'd failed to foresee

that the scientific discoveries he'd been such a part of

had such commercial potential.

The one patent he had managed to secure,

the crucial means of tuning a receiver

to a particular radio signal,

was bought off him by Marconi's powerful company.

Perhaps the worst indignation for Lodge, though,

would come in 1909,

when Marconi was awarded the Nobel Prize in Physics

for wireless communication.

It's difficult to imagine a bigger snub

to the physicist who'd so narrowly missed out to Hertz

in the discovery of radio waves,

and who'd then go on to show the world

how they could be sent and received.

But despite this snub, Lodge remained magnanimous,

using the new broadcasting technology

that resulted from his work, to give credit to others,

as this rare film of him shows.

Hertz made a great advance.

He discovered how to produce and detect waves in space,

thus bringing the ether into practical use, harnessing it,

harnessing it for the transmission of intelligence

in a way which has subsequently been elaborated

by a number of people.

Today, we can hardly imagine a world without broadcasting,

to imagine a time when radio waves

hadn't even been dreamt of.

Engineers continued to refine and perfect our ability

to transmit and receive electromagnetic waves,

but their initial discovery

was ultimately a triumph of pure science,

from Maxwell, through Hertz, to Lodge.

But still, the very nature

of electricity itself remained unexplained.

What created those electrical charges and currents

in the first place?

Although scientists were learning to exploit electricity,

they still didn't know what it actually was.

But this question was being answered

with experiments looking into

how electricity flowed through different materials.

Back in the 1850s, one of Germany's great experimentalists

and a talented glass blower, Heinrich Geissler,

created these beautiful showpieces.

Geissler pumped most of the air

out of these intricate glass tubes

and then had small amounts of other gases pumped in.

He then passed an electrical current through them.

They glowed with stunning colors,

and the current flowing through the gas seemed tangible.

Although they were designed purely for entertainment,

over the next 50 years,

scientists saw Geissler's tubes as a chance

to study how electricity flowed.

Efforts were made to pump more and more air

out of the tubes.

Could the electric current pass through nothingness,

through the vacuum?

This is a very rare flick book film of the British scientist

who created a vacuum good enough to answer that question.

His name was William Crookes.

Crookes create tubes like this.

He pumped out as much of the air as he could

so that it was as close to a vacuum as he could make it.

Then, when he passed an electric current through the tube.

He noticed a bright glow on the far end.

A beam seemed to be shining through the tube

and hitting the glass at the other end.

It seemed at last we could see electricity.

The beam became known as a cathode ray,

and this tube was the forerunner of the cathode ray tube

that was used in television sets for decades.

Physicist JJ Thomson discovered that these beams

were made up of tiny, negatively-charged particles,

and because they were carriers of electricity,

they became known as electrons.

Because the electrons only moved in one direction,

from the heated metal plate

through the positively-charged plate at the other end,

they behaved in exactly the same way

as Bose's semiconductor crystals.

But whereas Bose's crystals were naturally temperamental,

you had to find the right spot for them to work,

these tubes could be manufactured consistently.

They became known as valves,

and they soon replaced crystals in radio sets everywhere.

These discoveries would lead

to an explosion of new technology.

Early 20th century electronics

is all about what you can do with valves.

So, the radio industry is built on valves,

early television is built on valves,

early computers are built with valves.

These are what you build the electronic world with.

Having discovered how to manipulate

electrons flowing through a vacuum,

scientists were now keen to understand

how they could flow through other materials,

but that meant understanding

the things that made up materials:

Atoms.

It was in the early years of the 20th century

that we finally got a handle

on exactly what atoms were made up of and how they behaved,

and so what electricity actually was on the atomic scale.

At the University of Manchester, Ernest Rutherford's team

were studying the inner structure of the atom

and producing a picture

to describe what an atom looked like.

This revelation would finally help explain

some of the more puzzling features of electricity.

By 1913, the picture of the atom was one

in which you had a positively-charged nucleus in the middle

surrounded by negatively-charged orbiting electrons,

in patterns called shells.

Each of these shells corresponded

to an electron with a particular energy.

Now, given an energy boost, an electron could jump

from an inner shell to an outer one.

And the energy had to be just right,

if it wasn't enough,

the electron wouldn't make the transition.

And this boost was often temporary

because the electron would then drop back down again

to its original shell.

As it did this, it had to give off its excess energy

by spitting out a photon,

and the energy of each photon depended on its wavelength,

or as we would perceive it, its color.

Understanding the structure of atoms could now also explain

nature's great electrical light shows.

Just like Geissler's tubes,

the type of gas the electricity passes through

defines its color.

Lightning has a blue tinge

because of the nitrogen in our atmosphere.

Higher in the atmosphere, the gases are different

and so is the color of the photons they produce,

creating the spectacular auroras.

Understanding atoms, how they fit together in materials

and how their electrons behave,

was the final key to understanding

the fundamental nature of electricity.

This is a Wimshurst machine

and it's used to generate electric charge.

Electrons are rubbed off these discs

and start a flow of electricity

through the metal arms of the machine.

Now, metals conduct electricity

because the electrons are very weakly bound

inside their atoms

and so can slosh about and be used to flow as electricity.

Insulators on the other hand, don't conduct electricity

because the electrons are very tightly bound

inside the atoms

and are not free to move about.

The flow of electrons, and hence electricity,

through materials was now understood,

conductors and insulators could be explained.

What was more difficult to understand

was the strange properties of semiconductors.

Our modern electronic world is built upon semiconductors

and would grind to a halt without them.

Jagadish Chandra Bose

may have stumbled upon their properties back in the 1890s,

but no one could have foreseen

just how important they were to become.

But with the outbreak of the Second World War,

things were about to change.

Here in Oxford, this newly-built physics laboratory

was immediately handed over to the war research effort.

The researchers here were tasked

with improving the British radar system.

Radar was a technology that used electromagnetic waves

to detect enemy bombers, and as its accuracy improved,

it became clear that valves just weren't up to the job,

so the team had to turn to old technology:

Instead of valves, they used semiconductor crystals.

Now, they didn't use the same sort of crystals

that Bose had developed,

instead they used silicon.

This device is a silicon crystal receiver.

There's a tiny tungsten wire coiled down

and touching the surface of a little silicon crystal.

It's incredible how important a device it was.

It was the first time

silicon had really been exploited as a semiconductor,

but for it to work, it needed to be very pure,

and both sides in the war

put a lot of resources into purifying it.

In fact, the British had better silicon devices

so they must have had some coils of silicon

already at that time

which we were just starting with in Berlin.

The British had better silicon semiconductors

because they had help from laboratories in the US,

in particular, the famous Bell Labs.

And it wasn't long before physicists realized

that if semiconductors could replace valves in radar,

perhaps they could replace valves

in other devices too, like amplifiers.

The simple vacuum tube,

with its one-way stream of electrons,

had been modified to produce a new device.

By placing a metal grille in the path of the electrons

and applying a tiny voltage to it,

a dramatic change

in the strength of the beam could be produced.

These valves worked as amplifiers,

turning a very weak electrical signal

into a much stronger one.

An amplifier is something

that in one sense is really simple:

You just take a small current,

you turn it into a larger current.

But in other ways, it changes the world,

because when you can amplify a signal,

you can send it anywhere in the world.

As soon as the war was over, German expert Herbert Matare

and his colleague Heinrich Welker

started to build a semiconductor device

that could be used as an electrical amplifier.

And here is that first working model

that Matare and Welker made.

If you look inside, you can see the tiny crystal

and the wires that make contact with it.

If you pass a small current through one of the wires,

this allows a much larger current

to flow through the other one,

so it was acting as a signal amplifier.

These tiny devices could replace big, expensive valves

in long-distance telephone networks, radios,

and other equipment where a faint signal needed boosting.

Matare immediately realized what he'd created,

but his bosses were initially not interested.

Not, that is, until a paper appeared in a journal

announcing a Bell Labs discovery.

A research team there had stumbled across the same effect

and now they were announcing their invention to the world.

They called it the transistor.

They had it in December 1947,

and we had it in beginning '48.

But just, just life, you know,

they had it a little bit earlier, the effect.

But funnily enough, their transistors were just no good.

Although the European device was more reliable

than Bell Labs' more experimental model,

neither quite fulfilled their promise:

They worked, but were just too delicate,

so the search was on

for a more robust way to amplify electrical signals

and the breakthrough came by accident.

In Bell Labs, silicon crystal expert Russell Ohl

noticed that one of his silicon ingots

had a really bizarre property:

It seemed to be able to generate its own voltage.

And when he tried to measure this

by hooking it up to an oscilloscope,

he noticed that the voltage changed all the time.

The amount of voltage it generated seemed to depend on

how much light there was in the room.

So, by casting a shadow over the crystal,

he saw the voltage dropped;

More light meant the voltage went up.

What's more, when he turned a fan on

between the lamp and the crystal

the voltage started to oscillate with the same frequency

that the blades of the fan

were casting shadows over the crystal.

One of Ohl's colleagues immediately realized

that the ingot had a crack in it

that formed a natural junction,

and this tiny natural junction in an otherwise solid block

was acting just like the much more delicate junction

between the end of a wire and a crystal

that Bose had discovered,

except here it was sensitive to light.

The ingot had cracked because either side contained

slightly different amounts of impurities.

One side had slightly more of the element phosphorous,

while the other had slightly more

of a different impurity, boron,

and electrons seemed to be able to move across

from the phosphorous side to the boron side,

but not vice versa.

Photons of light shining down onto the crystal

were knocking electrons out of the atoms,

but it was the impurity atoms that were driving this flow.

Phosphorous has an electron that is going spare,

and boron is keen to accept another,

so electrons tended to flow from the phosphorous side

to the boron side

and crucially, only flowed one way across the junction.

The head of the semiconductor team, William Shockley,

saw the potential of this one-way junction within a crystal,

but how would it be possible to create a crystal

with two junctions in it that could be used as an amplifier?

Another researcher at Bell Labs called Gordon Teal

had been working on a technique that would allow just that.

He'd discovered a special way to grow single crystals

of the semiconductor germanium.

In this research institute, they grow semiconductor crystals

in the same way that Teal did back in Bell Labs,

only here, they grow them much, much bigger.

At the bottom of this vat is a container

with glowing-hot molten germanium,

just as pure as you can get it.

Inside it are a few atoms of whatever impurity is required

to alter its conductive properties.

Now, the rotating arm above has a seed crystal at the bottom

that has been dipped into the liquid

and will be slowly raised up again.

As the germanium cools and hardens, it forms a long crystal

like an icicle, below the seed.

The whole length is one single, beautiful germanium crystal.

Teal worked out that as the crystal is growing,

other impurities can be added to the vat and mixed in.

This gives us a single crystal

with thin layers of different impurities,

creating junctions within the crystal.

This crystal with two junctions in it was Shockley's dream.

Applying a small current

through the very thin middle section

allows a much larger current

to flow through the whole triple sandwich.

From a single crystal like this,

hundreds of tiny solid blocks could be cut,

each containing the two junctions

that would allow the movement of electrons through them

to be precisely controlled.

These tiny and reliable devices

could be used in all sorts of electrical equipment.

You cannot have the electronic equipment

that we have without tiny components.

And you get a weird effect actually,

the smaller they get, the more reliable they get,

it's a win-win situation.

The Bell Labs team were awarded the Nobel Prize

for their world-changing invention,

while the European team were forgotten.

William Shockley left Bell Labs,

and in 1955 set up his own semiconductor Laboratory

in rural California,

recruiting the country's best physics graduates.

But the celebratory mood didn't last long,

because Shockley was almost impossible to work for.

People left his company

because they just disliked the way he treated them.

So, the fact that Shockley was actually such a git

is why you have Silicon Valley.

It starts that whole process

of spin-off, and growth, and new companies,

and it all starts off

with Shockley being such a shocking human being.

The new companies were in competition with each other

to come up with the latest semiconductor devices.

They made transistors so small that huge numbers of them

could be incorporated into an electrical circuit

printed on a single slice of semiconductor crystal.

These tiny and reliable chips

could be used in all sorts of electrical equipment

most famously in computers:

A new age had dawned.

Today, microchips are everywhere,

they've transformed almost every aspect of modern life,

from communication, to transport and entertainment.

But perhaps just as importantly,

our computers have become so powerful

they're helping us to understand the Universe

in all its complexity.

A single microchip like this one today

can contain around four billion transistors.

It's incredible how far technology has come in 60 years.

It's easy to think that with the great leaps we've made

in understanding and exploiting electricity,

there's little left to learn about it.

But we'd be wrong.

For instance, making the circuits smaller and smaller

meant that a particular feature of electricity

that had been known about for over a century

was becoming more and more problematic:

Resistance.

A computer chip has to be continuously cooled.

If you take away the fan, this is what happens.

Wow, that's shooting up.

100, 120, 130 degrees.

200 degrees, and it cut out.

That just took a few seconds

and the chip is well and truly cooked.

You see, as the electrons flow through the chip,

they're not just traveling around unimpeded,

they're bumping into the atoms of silicon,

and the energy being lost by these electrons

is producing heat.

Now sometimes, this was useful,

inventors made electric heaters and ovens,

and whenever they got something to glow white-hot,

well, that's a light bulb.

But resistance in electronic apparatus and in power lines,

is a major waste of energy and a huge problem.

It's thought that resistance wastes

up to 20% of all the electricity we generate.

It's one of the greatest problems of modern times,

and the search is on

for a way to solve the problem of resistance.

What we think of as temperature is really a measure

of how much the atoms in a material are vibrating.

And if the atoms are vibrating,

then electrons flowing through

are more likely to bump into them.

So in general, the hotter the material,

the higher its electrical resistance,

and the cooler it is,

the lower the resistance.

But what happens if you cool something right down,

close to absolute zero, 273 degrees Celsius?

Well, at absolute zero there's no heat at all,

and so the atoms aren't moving at all.

What happens then to the flow of electricity,

the flow of electrons?

Using a special device called a cryostat,

that can keep things close to absolute zero,

we can find out.

Inside this cryostat, in this coil,

is mercury, the famous liquid metal,

and it forms part of an electric circuit.

Now, this equipment here

measures the resistance in the mercury,

but look what happens as I lower the mercury

into the coldest part of the cryostat.

There it is,

the resistance has dropped to absolutely nothing.

Mercury, like many substances we now know,

have this property,

it's called becoming superconducting,

which means they have no resistance at all

to the flow of electricity.

But these materials only work

when they're very, very cold.

If we could use a superconducting material

in our power cables and in our electronic apparatus,

we'd avoid losing so much

of our precious electrical energy through resistance.

The problem, of course,

is that superconductors had to be kept

at extremely low temperatures.

Then, in 1986, a breakthrough was made.

In a small laboratory

near Zurich, Switzerland,

IBM physicists recently discovered superconductivity

in a new class of materials

that is being called one of the most important

scientific breakthroughs in many decades.

This is a block of the same material

made by the researchers in Switzerland.

It doesn't look very remarkable,

but if you cool it down with liquid nitrogen,

something special happens:

It becomes a superconductor.

And because electricity and magnetism are so tightly linked,

that gives it equally extraordinary magnetic properties.

This magnet is suspended,

levitating above the superconductor.

The exciting thing is that although cold,

this material is way above absolute zero.

These magnetic fields are so strong

that not only can they support the weight of this magnet,

but they should also support MY weight.

I'm about to be levitated.

Oh, that's a very, very strange sensation.

When this material was first discovered in 1986,

it created a revolution.

Not only had no-one considered

that it might be superconducting,

but it was doing so at a temperature

much warmer than anyone had thought possible.

We are tantalizingly close

to getting room-temperature superconductors.

We're not there yet,

but one day, a new material will be found

and when we put that into our electronics equipment,

we could build a cheaper, better, more sustainable world.

Today, materials have been produced

that exhibit this phenomenon

at the sort of temperatures you get in your freezer,

but these new superconductors

can't be fully explained by the theoreticians.

So, without a complete understanding,

experimentalists are often guided as much by luck

as they are by a proper scientific understanding.

Recently, a laboratory in Japan held a party

in which they ended up dosing their superconductors

with a range of alcoholic beverages.

Unexpectedly, they found that red wine

improves the performance of the superconductors.

Electrical research now has the potential, once again,

to revolutionize our world

if room temperature superconductors can be found.

Our addiction to electricity's power is only increasing,

and when we fully understand how to exploit superconductors,

a new electrical world will be upon us.

It's going to lead to one of the most exciting periods

of human discovery and invention,

a brand-new set of tools, techniques, and technologies

to once again transform the world.

Electricity has changed our world:

Only a few hundred years ago,

it was seen as a mysterious and magical wonder.

Then, it leapt out of the laboratory

with a series of strange and wondrous experiments,

eventually being captured and put to use.

It revolutionized communication, first through cables,

and then as waves through electricity's far-reaching fields.

It powers and lights the modern world.

Today, we can hardly imagine life without electricity,

it defines our era,

and we would be utterly lost without it.

And yet, it still offers us more.

We stand, once again,

at the beginning of a new age of discovery,

a new revolution.

But above all else, there's one thing

that all those who deal in the science of electricity know:

Its story is not over yet.