0:00:08 > 0:00:11On the 14th August 1894,
0:00:11 > 0:00:15an excited crowd gathered outside Oxford's Natural History Museum.
0:00:18 > 0:00:22This huge Gothic building was hosting the annual meeting
0:00:22 > 0:00:26of the British Association for the Advancement of Science.
0:00:27 > 0:00:30Over 2,000 tickets had been sold in advance
0:00:30 > 0:00:33and the museum was already packed,
0:00:33 > 0:00:37waiting for the next talk to be given by Professor Oliver Lodge.
0:00:40 > 0:00:43His name might not be familiar to us now,
0:00:43 > 0:00:46but his discoveries should have made him as famous
0:00:46 > 0:00:50as some of the other great electrical pioneers of history.
0:00:50 > 0:00:53People like Benjamin Franklin,
0:00:53 > 0:00:56Alessandro Volta,
0:00:56 > 0:00:59or even the great Michael Faraday.
0:00:59 > 0:01:05Quite unwittingly, he would set in motion a series of events
0:01:05 > 0:01:08that would revolutionise the Victorian world
0:01:08 > 0:01:10of brass and telegraph wire.
0:01:10 > 0:01:15This lecture would mark the birth of the modern electrical world,
0:01:15 > 0:01:19a world dominated by silicone and mass wireless communication.
0:01:24 > 0:01:29In this programme, we discover how electricity connected the world together
0:01:29 > 0:01:33through broadcasting and computer networks,
0:01:33 > 0:01:37and how we finally learnt to unravel and exploit electricity
0:01:37 > 0:01:41at an atomic level.
0:01:41 > 0:01:46After centuries of man's experiments with electricity,
0:01:46 > 0:01:50a new age of real understanding was now dawning.
0:02:15 > 0:02:19These tubes are not plugged in to any power source,
0:02:19 > 0:02:22but they still light up.
0:02:22 > 0:02:25It's electricity's invisible effect,
0:02:25 > 0:02:28an effect not just confined to the wires it flows through.
0:02:31 > 0:02:33In the middle of the 19th century,
0:02:33 > 0:02:37a great theory was proposed to explain how this could be.
0:02:39 > 0:02:43The theory says that surrounding any electric charge -
0:02:43 > 0:02:46and there's a lot of electricity flowing above my head -
0:02:46 > 0:02:48is a force field.
0:02:48 > 0:02:53These florescent tubes are lit purely because they are under
0:02:53 > 0:02:58the influence of the force field from the power cables above.
0:03:00 > 0:03:04The theory that a flow of electricity could, in some way,
0:03:04 > 0:03:07create an invisible force field, was originally proposed
0:03:07 > 0:03:13by Michael Faraday, but it would take a brilliant young Scotsman
0:03:13 > 0:03:18called James Clark-Maxwell, who would prove Faraday correct -
0:03:18 > 0:03:22and not through experimentation, but through mathematics.
0:03:23 > 0:03:28This was all a far cry from the typical 19th century way
0:03:28 > 0:03:30of understanding how the world works,
0:03:30 > 0:03:35which was essentially to see it as a physical machine.
0:03:42 > 0:03:47Before Maxwell, scientists had often built strange machines
0:03:47 > 0:03:51or devised wondrous experiments to create and measure electricity.
0:03:53 > 0:03:55But Maxwell was different.
0:03:55 > 0:04:00He was interested in the numbers, and his new theory not only revealed
0:04:00 > 0:04:05electricity's invisible force field, but how it could be manipulated.
0:04:05 > 0:04:08It would prove to be one of the most important
0:04:08 > 0:04:11scientific discoveries of all time.
0:04:11 > 0:04:14Maxwell was a mathematician and a great one
0:04:14 > 0:04:17and he saw electricity and magnetism in an entirely new way.
0:04:17 > 0:04:21He expressed it all in terms of very compact mathematical equations.
0:04:21 > 0:04:25And the most important thing is that in Maxwell's equations
0:04:25 > 0:04:31is an understanding of electricity and magnetism as something linked
0:04:31 > 0:04:34and as something that can occur in waves.
0:04:42 > 0:04:47Maxwell's calculations showed how these fields could be disturbed
0:04:47 > 0:04:52rather like touching the surface of water with your finger.
0:04:52 > 0:04:55Changing the direction of the electric current
0:04:55 > 0:04:57would create a ripple or wave
0:04:57 > 0:05:00through these electric and magnetic fields.
0:05:00 > 0:05:03And constantly changing the direction
0:05:03 > 0:05:06of the flow of the current, forwards and backwards,
0:05:06 > 0:05:12like an alternating current, would produce a whole series of waves,
0:05:12 > 0:05:15waves that would carry energy.
0:05:17 > 0:05:22Maxwell's maths was telling him that changing electric currents
0:05:22 > 0:05:25would be constantly sending out great waves of energy
0:05:25 > 0:05:27into their surroundings.
0:05:27 > 0:05:30Waves that would carry on forever unless something absorbed them.
0:05:43 > 0:05:47Maxwell's maths was so advanced and complicated
0:05:47 > 0:05:51that only a handful of people understood it at the time,
0:05:51 > 0:05:54and although his work was still only a theory,
0:05:54 > 0:06:00it inspired a young German physicist called Heinrich Hertz.
0:06:00 > 0:06:05Hertz decided to dedicate himself to designing an experiment
0:06:05 > 0:06:09to prove that Maxwell's waves really existed.
0:06:11 > 0:06:12And here it is.
0:06:12 > 0:06:16This is Hertz's original apparatus
0:06:16 > 0:06:20and its beauty is in its sheer simplicity.
0:06:20 > 0:06:24Heat generates and alternating current that runs
0:06:24 > 0:06:27along these metal rods, with a spark that jumps across the gap
0:06:27 > 0:06:29between these two spheres.
0:06:29 > 0:06:32Now, if Maxwell was right,
0:06:32 > 0:06:36then this alternating current should generate an invisible
0:06:36 > 0:06:40electromagnetic wave that spreads out into the surroundings.
0:06:40 > 0:06:44If you place a wire in the path of that wave,
0:06:44 > 0:06:50then at the wire, there should be a changing electromagnetic field,
0:06:50 > 0:06:54which should induce an electric current in the wire.
0:06:54 > 0:06:59So what Hertz did was build this ring of wire, his receiver,
0:06:59 > 0:07:02that he could carry around in different positions in the room
0:07:02 > 0:07:06to see if he could detect the presence of the wave.
0:07:06 > 0:07:10And the way he did that was leave a very tiny gap in the wire,
0:07:10 > 0:07:17across which a spark would jump if a current runs through the ring.
0:07:17 > 0:07:22Now, because the current is so weak, that spark is very, very faint
0:07:22 > 0:07:26and Hertz spent pretty much most of 1887
0:07:26 > 0:07:31in a darkened room staring intensely through a lens
0:07:31 > 0:07:35to see if he could detect the presence of this faint spark.
0:07:43 > 0:07:47But Hertz wasn't alone in trying to create Maxwell's waves.
0:07:48 > 0:07:53Back in England, a young physics Professor called Oliver Lodge
0:07:53 > 0:07:55had been fascinated by the topic for years
0:07:55 > 0:07:59but hadn't had the time to design any experiments
0:07:59 > 0:08:01to try to discover them.
0:08:03 > 0:08:08Then one day, in early 1888, while setting up an experiment
0:08:08 > 0:08:12on lightning protection, he noticed something unusual.
0:08:15 > 0:08:18Lodge noticed that when he set up his equipment
0:08:18 > 0:08:22and sent an alternating current around the wires,
0:08:22 > 0:08:26he could see glowing patches between the wires,
0:08:26 > 0:08:28and with a bit of tweaking,
0:08:28 > 0:08:32he saw these glowing patches formed a pattern.
0:08:32 > 0:08:36The blue glow and electrical sparks occurred in distinct patches
0:08:36 > 0:08:39evenly spaced along the wires.
0:08:39 > 0:08:43He realised they were the peaks and troughs of a wave,
0:08:43 > 0:08:45an invisible electromagnetic wave.
0:08:47 > 0:08:50Lodge had proved that Maxwell was right.
0:08:51 > 0:08:54Finally, by accident, Lodge had created
0:08:54 > 0:08:59Maxwell's electromagnetic waves around the wires.
0:08:59 > 0:09:02The big question had been answered.
0:09:04 > 0:09:08Filled with excitement at his discovery, Lodge prepared
0:09:08 > 0:09:13to announce it to the world, at that summer's annual scientific meeting
0:09:13 > 0:09:15run by the British Association.
0:09:17 > 0:09:20Before it, though, he decided to go on holiday.
0:09:20 > 0:09:25His timing couldn't have been worse, because back in Germany,
0:09:25 > 0:09:27and at exactly the same time,
0:09:27 > 0:09:31Heinrich Hertz was also testing Maxwell's theories.
0:09:35 > 0:09:39Eventually, Hertz found what he was looking for...
0:09:39 > 0:09:42a minute spark.
0:09:42 > 0:09:46And as he carried his receiver to different positions in the room,
0:09:46 > 0:09:50he was able to map out the shape of the waves
0:09:50 > 0:09:52being produced by his apparatus.
0:09:52 > 0:09:56And he checked each of Maxwell's calculations carefully
0:09:56 > 0:09:58and tested them experimentally.
0:09:58 > 0:10:02It was a "tour de force" of experimental science.
0:10:07 > 0:10:08Back in Britain,
0:10:08 > 0:10:11as the crowds gathered for the British Association meeting,
0:10:11 > 0:10:17Oliver Lodge returned from holiday relaxed and full of anticipation.
0:10:21 > 0:10:25This, Lodge thought, would be his moment of triumph,
0:10:25 > 0:10:29when he could announce his discovery of Maxwell's waves.
0:10:29 > 0:10:35His great friend, the mathematician Fitzgerald, was due to give the opening address in the meeting.
0:10:35 > 0:10:42But in it, he proclaimed that Heinrik Hertz had just published astounding results.
0:10:42 > 0:10:46He had detected Maxwell's waves travelling through space.
0:10:46 > 0:10:50"We have snatched the thunderbolt from Jove himself
0:10:50 > 0:10:54"and enslaved the all prevailing ether", he announced.
0:10:54 > 0:10:58Well, I can only imagine how Lodge must have felt
0:10:58 > 0:11:00having his thunder stolen.
0:11:02 > 0:11:06Professor Oliver Lodge had lost his moment of triumph,
0:11:06 > 0:11:11pipped at the post by Heinrich Hertz.
0:11:11 > 0:11:15Hertz's spectacular demonstration of electromagnetic waves, what we now call radio waves,
0:11:15 > 0:11:21though he didn't know it at the time, will lead to a whole revolution in communications over the next century.
0:11:26 > 0:11:30Maxwell's theory had shown how electric charges could create
0:11:30 > 0:11:33a force field around them.
0:11:33 > 0:11:37And that waves could spread through these fields like ripples on a pond.
0:11:40 > 0:11:43And Hertz had built a device that could actually create
0:11:43 > 0:11:47and detect the waves as they passed through the air.
0:11:48 > 0:11:50But, almost immediately,
0:11:50 > 0:11:55there would be another revelation in our understanding of electricity.
0:11:55 > 0:11:59A revelation that would once again involve Professor Oliver Lodge.
0:11:59 > 0:12:03And, once again, his thunder would be stolen.
0:12:16 > 0:12:21The story starts in Oxford, in the summer of 1894.
0:12:21 > 0:12:24Hertz had died suddenly earlier that year,
0:12:24 > 0:12:28and so Lodge prepared a memorial lecture with a demonstration
0:12:28 > 0:12:34that would bring the idea of waves to a wider audience.
0:12:34 > 0:12:36Lodge had worked on his lecture.
0:12:36 > 0:12:40He'd researched better ways of detecting the waves,
0:12:40 > 0:12:43and he'd borrowed new apparatus from friends.
0:12:43 > 0:12:48He'd made some significant advances in the technology
0:12:48 > 0:12:51designed to detect the waves.
0:12:51 > 0:12:56This bit of apparatus generates an alternating current
0:12:56 > 0:12:57and a spark across this gap.
0:12:59 > 0:13:04The alternating current sends out an electromagnetic wave,
0:13:04 > 0:13:08just as Maxwell predicted, that is picked up by the receiver.
0:13:08 > 0:13:14It sets off a very weak electric current through these two antennae.
0:13:14 > 0:13:16Now, this is what Hertz had done.
0:13:16 > 0:13:22Lodge's improvement on this was to set up this tube full of iron fillings.
0:13:22 > 0:13:25The weak electric current passes through the filings,
0:13:25 > 0:13:28forcing them to clump together.
0:13:28 > 0:13:31And, when they do, they close a second electric circuit
0:13:31 > 0:13:33and set off the bell.
0:13:33 > 0:13:36So if I push the button on this end...
0:13:36 > 0:13:39- BELL TINKLES - ..it sets off the bell at the receiver.
0:13:39 > 0:13:43And it's doing that with no connections between the two.
0:13:43 > 0:13:44It's like magic.
0:13:44 > 0:13:51BELL RINGING/ELECTRICAL BUZZING
0:13:51 > 0:13:53If you could imagine a packed house,
0:13:53 > 0:13:58lots of people in the audience, and what they suddenly see is,
0:13:58 > 0:14:01as if by magic, a bell ringing.
0:14:01 > 0:14:03It's quite incredible.
0:14:03 > 0:14:05BELL RINGS
0:14:05 > 0:14:10It might not have been the most dramatic demonstration the audience had ever seen,
0:14:10 > 0:14:14but it certainly still created a sensation among the crowd.
0:14:14 > 0:14:17Lodge's apparatus, laid out like this,
0:14:17 > 0:14:20no longer looked like a scientific experiment.
0:14:20 > 0:14:24In fact, it looked remarkably like those telegraph machines
0:14:24 > 0:14:30that had revolutionised communication, but without those long cables
0:14:30 > 0:14:34stretching between the sending and receiving stations.
0:14:34 > 0:14:37To the more worldly and savvy members of the audience,
0:14:37 > 0:14:42this was clearly more than showing the maestro Maxwell was right.
0:14:42 > 0:14:47This was a revolutionary new form of communication.
0:14:52 > 0:14:56Lodge published his lecture notes on how electromagnetic waves
0:14:56 > 0:15:00could be sent and received using his new improvements.
0:15:00 > 0:15:04All around the world, inventors, amateur enthusiasts
0:15:04 > 0:15:07and scientists read Lodge's reports with excitement
0:15:07 > 0:15:11and began experimenting with Hertzian waves.
0:15:14 > 0:15:19Two utterly different characters were to be inspired by it.
0:15:19 > 0:15:23Both would bring improvements to the wireless telegraph,
0:15:23 > 0:15:30and both would be remembered for their contribution to science far more than Oliver Lodge.
0:15:30 > 0:15:34The first was Guglielmo Marconi.
0:15:34 > 0:15:36Marconi was a very intelligent, astute
0:15:36 > 0:15:38and a very charming individual.
0:15:38 > 0:15:41He definitely had the Italian, Irish charm.
0:15:41 > 0:15:49He could apply this to almost anyone from sort of young ladies to world-renowned scientists.
0:15:49 > 0:15:51Marconi was no scientist,
0:15:51 > 0:15:55but he read all he could of other people's work
0:15:55 > 0:15:59in order to put together his own wireless telegraph system.
0:15:59 > 0:16:04It's possible that because he was brought up in Bologna and it was fairly close to the Italian coast,
0:16:04 > 0:16:11that he saw the potential of wireless communications in relation to maritime usage fairly early on.
0:16:11 > 0:16:15Then, aged only 22, he came to London
0:16:15 > 0:16:17with his Irish mother to market it.
0:16:20 > 0:16:25The other person inspired by Lodge's lecture was a teacher
0:16:25 > 0:16:28at the Presidency College in Calcutta,
0:16:28 > 0:16:31called Jagadish Chandra Bose.
0:16:31 > 0:16:35Despite degrees from London and Cambridge,
0:16:35 > 0:16:42the appointment of an Indian as a scientist in Calcutta had been a battle against racial prejudice.
0:16:44 > 0:16:50Indians, it was said, didn't have the requisite temperament for exact science.
0:16:50 > 0:16:53Well, Bose was determined to prove this wrong,
0:16:53 > 0:16:57and here in the archives, we can see just how fast he set to work.
0:16:58 > 0:17:04This is a report of the 66th meeting of the British Association
0:17:04 > 0:17:06in Liverpool, September 1896.
0:17:06 > 0:17:09And here is Bose,
0:17:09 > 0:17:13the first Indian ever to present at the association meeting,
0:17:13 > 0:17:17talking about his work and demonstrating his apparatus.
0:17:17 > 0:17:22He'd built and improved on the detector that Lodge described,
0:17:22 > 0:17:25because in the hot, sticky Indian climate,
0:17:25 > 0:17:30he'd found that the metal filings inside the tube that Lodge used to detect the waves
0:17:30 > 0:17:32became rusty and stuck together.
0:17:32 > 0:17:38So Bose had to build a more practical detector using a coiled wire instead.
0:17:38 > 0:17:41His work was described as a sensation.
0:17:43 > 0:17:47The detector was extremely reliable and could work onboard ships,
0:17:47 > 0:17:52so had great potential for the vast British naval fleet.
0:17:52 > 0:17:56Britain was the centre of a vast telecommunications network
0:17:56 > 0:17:58which stretched almost around the world,
0:17:58 > 0:18:04which was used to support an equally vast maritime network of
0:18:04 > 0:18:08merchant and naval vessels, which were used to support the British Empire.
0:18:09 > 0:18:16But Bose, a pure scientist, wasn't interested in the commercial potential of wireless signals...
0:18:16 > 0:18:18unlike Marconi.
0:18:18 > 0:18:23This was sort of a new, cutting-edge field, but Marconi
0:18:23 > 0:18:27wasn't a trained scientist, so he came at things in a different way,
0:18:27 > 0:18:32which may have been why he progressed so quickly in the first place.
0:18:32 > 0:18:35And he was very good at forming connections with the people
0:18:35 > 0:18:39he needed to form connections with, to enable his work to be done.
0:18:41 > 0:18:45Marconi used his connections to go straight to the only place
0:18:45 > 0:18:47that had the resources to help him.
0:18:52 > 0:18:55The British Post Office was a hugely powerful institution.
0:18:55 > 0:18:59When Marconi first arrived in London in 1896,
0:18:59 > 0:19:04these buildings were newly completed and already heaving with business
0:19:04 > 0:19:08from the empire's postal and telegraphy services.
0:19:08 > 0:19:12Marconi had brought his telegraph system with him from Italy,
0:19:12 > 0:19:17claiming it could send wireless signals over unheard of distances.
0:19:17 > 0:19:20And the Post Office Engineer-in-Chief,
0:19:20 > 0:19:24William Preece, immediately saw the technology's potential.
0:19:26 > 0:19:31So, Preece offered Marconi the great financial and engineering resources
0:19:31 > 0:19:36of the Post Office, and they started work up on the roof.
0:19:38 > 0:19:42The old headquarters of the Post Office were right there.
0:19:42 > 0:19:46And between this roof and that one, Marconi and the Post Office engineers
0:19:46 > 0:19:51would practise sending and receiving electromagnetic waves.
0:19:51 > 0:19:57The engineers helped him improve his apparatus, and then Preece and Marconi together
0:19:57 > 0:20:01demonstrated it to influential people in Government and the Navy.
0:20:05 > 0:20:07What Preece didn't realise
0:20:07 > 0:20:13was that even as he was proudly announcing Marconi's successful partnership with the Post Office,
0:20:13 > 0:20:16Marconi was making plans behind the scenes.
0:20:18 > 0:20:22He'd applied for a British patent on the whole field of wireless telegraphy
0:20:22 > 0:20:26and was planning on setting up his own company.
0:20:26 > 0:20:30When the patent was granted, all hell broke loose
0:20:30 > 0:20:33in the scientific community.
0:20:37 > 0:20:40That patent was itself revolutionary.
0:20:43 > 0:20:46You see, patents could only be taken out on things
0:20:46 > 0:20:48that weren't public knowledge,
0:20:48 > 0:20:53but Marconi famously had hidden his equipment in a secret box.
0:20:58 > 0:21:00And here it is.
0:21:00 > 0:21:02When his patent was finally granted,
0:21:02 > 0:21:06Marconi ceremoniously opened the box.
0:21:06 > 0:21:09Everyone was keen to see what inventions lay within.
0:21:13 > 0:21:15Batteries forming a circuit,
0:21:15 > 0:21:18iron filings in the tube to complete the circuit
0:21:18 > 0:21:20to ring the bell on top.
0:21:20 > 0:21:26Nothing they hadn't seen before, and yet, Marconi had patented the lot.
0:21:28 > 0:21:32The reason Marconi is famous is not because of that invention.
0:21:32 > 0:21:35He doesn't invent radio, but he improves it
0:21:35 > 0:21:37and turns it into a system.
0:21:37 > 0:21:41Lodge doesn't do that. And that's why we remember Marconi,
0:21:41 > 0:21:44and that's why we don't remember Lodge.
0:21:48 > 0:21:51The scientific world was up in arms.
0:21:51 > 0:21:56Here was this young man who knew very little about the science behind his equipment
0:21:56 > 0:22:00about to make his fortune, from their work.
0:22:00 > 0:22:04Even his great supporter Preece, was disappointed and hurt
0:22:04 > 0:22:09when he found out Marconi was about to go it alone and set up his own company.
0:22:09 > 0:22:14Lodge and other scientists began a frenzy of patenting
0:22:14 > 0:22:18every tiny detail and improvement they made to their equipment.
0:22:21 > 0:22:26This new atmosphere shocked Bose when he returned to Britain.
0:22:28 > 0:22:32Bose wrote home to India in disgust at what he found in England.
0:22:32 > 0:22:37"Money, money, money all the time, what a devouring greed!
0:22:37 > 0:22:43"I wish you could see the craze for money of the people here."
0:22:43 > 0:22:46His disillusionment with the changes he saw
0:22:46 > 0:22:53in the country he revered for scientific integrity and excellence is palpable.
0:22:53 > 0:22:55Eventually, though, it was his friends
0:22:55 > 0:22:59who convinced Bose to take out his one and only patent,
0:22:59 > 0:23:04on his discovery of a new kind of detector for waves.
0:23:04 > 0:23:10It was this discovery that would lead to perhaps an even greater revolution for the world.
0:23:10 > 0:23:14He had discovered the power of crystals.
0:23:16 > 0:23:19This replaces older techniques using iron filings, which are
0:23:19 > 0:23:21messy and difficult and don't work well.
0:23:21 > 0:23:25And here's a whole new way of detecting radio waves,
0:23:25 > 0:23:28and it's one that's going to be at the centre of a radio industry.
0:23:29 > 0:23:32Bose's discovery was simple,
0:23:32 > 0:23:36but it would truly shape the modern world.
0:23:36 > 0:23:42When some crystals are touched with metal to test their electrical conductivity,
0:23:42 > 0:23:46they can show rather odd and varied behaviour.
0:23:46 > 0:23:49Take this crystal, for example.
0:23:49 > 0:23:53If I can touch it in exactly the right spot with the tip of this metal wire,
0:23:53 > 0:23:57and then hook it up to a battery,
0:23:57 > 0:23:59it gives quite a significant current.
0:24:01 > 0:24:04But if I switch round my connections to the battery
0:24:04 > 0:24:08and try and pass the current through in the opposite direction...
0:24:08 > 0:24:10it's a lot less.
0:24:12 > 0:24:18It's not a full conductor of electricity, it's a semi-conductor.
0:24:18 > 0:24:23And it found its first use in detecting electromagnetic waves.
0:24:23 > 0:24:27When Bose used a crystal like this in his circuits
0:24:27 > 0:24:30instead of the tube of filings,
0:24:30 > 0:24:36he found it was a much more efficient and effective detector of electromagnetic waves.
0:24:36 > 0:24:41It was this strange property of the junction between the wire,
0:24:41 > 0:24:45known as the "cat's whisker", and the crystal, which allowed current to pass
0:24:45 > 0:24:49much more easily on one direction than the other,
0:24:49 > 0:24:54that meant it could be used to extract a signal from electromagnetic waves.
0:24:56 > 0:25:03At the time, no-one had any idea why certain crystals acted in this way.
0:25:03 > 0:25:07But to scientists and engineers, this strange behaviour
0:25:07 > 0:25:11had a profound and almost miraculous practical effect.
0:25:12 > 0:25:16With crystals as detectors,
0:25:16 > 0:25:25now it was possible to broadcast and detect the actual sound of a human voice, or music.
0:25:36 > 0:25:38In his Oxford lecture in 1894,
0:25:38 > 0:25:42Oliver Lodge had opened a Pandora's box.
0:25:42 > 0:25:49As an academic, he'd failed to foresee that the scientific discoveries he'd been such a part of
0:25:49 > 0:25:52had such commercial potential.
0:25:52 > 0:25:54The one patent he had managed to secure,
0:25:54 > 0:25:59the crucial means of tuning a receiver to a particular radio signal,
0:25:59 > 0:26:04was bought off him by Marconi's powerful company.
0:26:09 > 0:26:12Perhaps the worst indignation for Lodge, though,
0:26:12 > 0:26:14would come in 1909,
0:26:14 > 0:26:19when Marconi was awarded the Nobel Prize in Physics for wireless communication.
0:26:21 > 0:26:25It's difficult to imagine a bigger snub to the physicist
0:26:25 > 0:26:29who'd so narrowly missed out to Hertz in the discovery of radio waves,
0:26:29 > 0:26:31and who'd then go on to show the world
0:26:31 > 0:26:34how they could be sent and received.
0:26:36 > 0:26:40'But despite this snub, Lodge remained magnanimous,
0:26:40 > 0:26:44'using the new broadcasting technology that resulted from his work
0:26:44 > 0:26:46'to give credit to others,
0:26:46 > 0:26:49'as this rare film of him shows.'
0:26:49 > 0:26:51Hertz made a great advance.
0:26:53 > 0:26:57He discovered how to produce and detect waves in space,
0:26:57 > 0:27:00thus bringing the ether into practical use.
0:27:01 > 0:27:05Harnessing it, harnessing it for the transmission of intelligence
0:27:05 > 0:27:09in a way which has subsequently been elaborated by a number of people.
0:27:21 > 0:27:26Today, we can hardly imagine a world without broadcasting,
0:27:26 > 0:27:29to imagine a time when radio waves hadn't even been dreamt of.
0:27:31 > 0:27:35Engineers continued to refine and perfect our ability
0:27:35 > 0:27:38to transmit and receive electromagnetic waves,
0:27:38 > 0:27:44but their discovery was ultimately a triumph of pure science,
0:27:44 > 0:27:47from Maxwell, through Hertz, to Lodge.
0:27:47 > 0:27:53But still, the very nature of electricity itself remained unexplained.
0:27:53 > 0:27:58What created those electrical charges and currents in the first place?
0:28:00 > 0:28:04Although scientists were learning to exploit electricity,
0:28:04 > 0:28:09they still didn't know what it actually was.
0:28:09 > 0:28:12But this question was being answered with experiments
0:28:12 > 0:28:16looking into how electricity flowed through different materials.
0:28:17 > 0:28:22Back in the 1850s, one of Germany's great experimentalists
0:28:22 > 0:28:25and a talented glass blower, Heinrich Geissler,
0:28:25 > 0:28:28created these beautiful showpieces.
0:28:28 > 0:28:31ELECTRICITY BUZZES
0:28:37 > 0:28:42Geissler pumped most of the air out of these intricate glass tubes
0:28:42 > 0:28:45and then had small amounts of other gases pumped in.
0:28:49 > 0:28:52He then passed an electrical current through them.
0:28:52 > 0:28:55They glowed with stunning colours,
0:28:55 > 0:28:59and the current flowing through the gas seemed tangible.
0:29:01 > 0:29:04Although they were designed purely for entertainment,
0:29:04 > 0:29:09over the next 50 years, scientists saw Giessler's tubes as a chance
0:29:09 > 0:29:12to study how electricity flowed.
0:29:14 > 0:29:18Efforts were made to pump more and more air out of the tubes.
0:29:18 > 0:29:22Could the electric current pass through nothingness?
0:29:22 > 0:29:24Through the vacuum?
0:29:28 > 0:29:34This is a very rare flick book film of the British scientist
0:29:34 > 0:29:38who created a vacuum good enough to answer that question.
0:29:38 > 0:29:40His name was William Crookes.
0:29:42 > 0:29:45Crookes create tubes like this.
0:29:45 > 0:29:48He pumped out as much of the air as he could
0:29:48 > 0:29:52so that it was as close to a vacuum as he could make it.
0:29:52 > 0:29:55Then, when he passed an electrical current through the tube...
0:29:55 > 0:29:58ELECTRICAL BUZZING
0:29:58 > 0:30:02..he noticed a bright glow on the far end.
0:30:02 > 0:30:05A beam seemed to be shining through the tube
0:30:05 > 0:30:08and hitting the glass at the other end.
0:30:08 > 0:30:11It seemed, at last, we could see electricity.
0:30:11 > 0:30:14The beam became known as a cathode ray,
0:30:14 > 0:30:18and this tube was the forerunner of the cathode ray tube
0:30:18 > 0:30:22that was used in television sets for decades.
0:30:26 > 0:30:31Physicist JJ Thompson discovered that these beams
0:30:31 > 0:30:35were made up of tiny, negatively charged particles,
0:30:35 > 0:30:41and because they were carriers of electricity, they became known as electrons.
0:30:42 > 0:30:45Because the electrons only moved in one direction,
0:30:45 > 0:30:50from the heated metal plate through the positively charged plate at the other end,
0:30:50 > 0:30:55they behaved in exactly the same way as Bose's semi-conductor crystals.
0:30:55 > 0:30:59But, whereas Bose's crystals were naturally temperamental -
0:30:59 > 0:31:02you had to find the right spot for them to work -
0:31:02 > 0:31:05these tubes could be manufactured consistently.
0:31:06 > 0:31:08They became known as valves,
0:31:08 > 0:31:13and they soon replaced crystals in radio sets everywhere.
0:31:17 > 0:31:21These discoveries would lead to an explosion of new technology.
0:31:22 > 0:31:27Early 20th century electronics is all about what you can do with valves.
0:31:27 > 0:31:30So, the radio industries is built on valves,
0:31:30 > 0:31:32early television is built on valves,
0:31:32 > 0:31:34early computers are built with valves.
0:31:34 > 0:31:37These are what you build the electronic world with.
0:31:39 > 0:31:44Having discovered how to manipulate electrons flowing through a vacuum,
0:31:44 > 0:31:47scientists were now keen to understand
0:31:47 > 0:31:50how they could flow through other materials.
0:31:51 > 0:31:56But that meant understanding the things that made up materials -
0:31:56 > 0:31:57atoms.
0:32:07 > 0:32:12It was in the early years of the 20th century that we finally
0:32:12 > 0:32:17got a handle on exactly what atoms were made up of and how they behaved.
0:32:18 > 0:32:22And so, what electricity actually was on the atomic scale.
0:32:25 > 0:32:29At the University of Manchester, Ernest Rutherford's team
0:32:29 > 0:32:31were studying the inner structure of the atom
0:32:31 > 0:32:36and producing a picture to describe what an atom looked like.
0:32:36 > 0:32:43This revelation would finally help explain some of the more puzzling features of electricity.
0:32:43 > 0:32:47By 1913, the picture of the atom was one in which you had
0:32:47 > 0:32:50a positively charged nucleus in the middle
0:32:50 > 0:32:55surrounded by negatively charged orbiting electrons,
0:32:55 > 0:32:57in patterns called shells.
0:32:57 > 0:33:02Each of these shells corresponded to an electron with a particular energy.
0:33:02 > 0:33:06Now, given an energy boost, an electron could jump
0:33:06 > 0:33:09from an inner shell to an outer one.
0:33:09 > 0:33:11And the energy had to be just right -
0:33:11 > 0:33:15if it wasn't enough, the electron wouldn't make the transition.
0:33:15 > 0:33:18And this boost was often temporary because the electron
0:33:18 > 0:33:22would then drop back down again to its original shell.
0:33:22 > 0:33:25As it did this, it had to give off its excess energy
0:33:25 > 0:33:27by spitting out a photon...
0:33:28 > 0:33:33..and the energy of each photon depended on its wavelength,
0:33:33 > 0:33:36or, as we would perceive it, its colour.
0:33:39 > 0:33:43Understanding the structure of atoms could now also explain
0:33:43 > 0:33:45nature's great electrical light shows.
0:33:45 > 0:33:48THUNDER
0:33:48 > 0:33:50Just like Geissler's tubes,
0:33:50 > 0:33:54the type of gas the electricity passes through defines its colour.
0:33:58 > 0:34:03Lightning has a blue tinge because of the nitrogen in our atmosphere.
0:34:04 > 0:34:08Higher in the atmosphere, the gases are different
0:34:08 > 0:34:12and so is the colour of the photons they produce,
0:34:12 > 0:34:14creating the spectacular auroras.
0:34:20 > 0:34:24Understanding atoms, how they fit together in materials
0:34:24 > 0:34:29and how their electrons behave, was the final key to understanding
0:34:29 > 0:34:32the fundamental nature of electricity.
0:34:38 > 0:34:40This is a Wimshurst Machine
0:34:40 > 0:34:43and it's used to generate electric charge.
0:34:45 > 0:34:50Electrons are rubbed off these discs and start a flow of electricity
0:34:50 > 0:34:53through the metal arms of the machine.
0:34:55 > 0:34:57Now, metals conduct electricity
0:34:57 > 0:35:01because the electrons are very weakly bound inside their atoms
0:35:01 > 0:35:06and so can slosh about and be used to flow as electricity.
0:35:06 > 0:35:09Insulators, on the other hand, don't conduct electricity
0:35:09 > 0:35:13because the electrons are very tightly bound inside the atoms
0:35:13 > 0:35:15and are not free to move about.
0:35:17 > 0:35:20The flow of electrons, and hence electricity,
0:35:20 > 0:35:22through materials was now understood.
0:35:22 > 0:35:26Conductors and insulators could be explained.
0:35:26 > 0:35:28What was more difficult to understand
0:35:28 > 0:35:31was the strange properties of semi-conductors.
0:35:34 > 0:35:39Our modern electronic world is built upon semi-conductors
0:35:39 > 0:35:42and would grind to a halt without them.
0:35:42 > 0:35:48Jagadish Chandra Bose may have stumbled upon their properties back in the 1890s,
0:35:48 > 0:35:54but no-one could have foreseen just how important they were to become.
0:35:55 > 0:35:58But, with the outbreak of the Second World War,
0:35:58 > 0:36:00things were about to change.
0:36:06 > 0:36:09Here in Oxford, this newly built physics laboratory
0:36:09 > 0:36:13was immediately handed over to the war research effort.
0:36:13 > 0:36:17The researchers here were tasked with improving the British radar system.
0:36:23 > 0:36:27Radar was a technology that used electromagnetic waves
0:36:27 > 0:36:31to detect enemy bombers, and as its accuracy improved,
0:36:31 > 0:36:35it became clear that valves just weren't up to the job.
0:36:39 > 0:36:42So, the team had to turn to old technology -
0:36:42 > 0:36:47instead of valves, they used semi-conductor crystals.
0:36:47 > 0:36:50Now, they didn't use the same sort of crystals
0:36:50 > 0:36:53that Bose had developed - instead they used silicon.
0:36:56 > 0:37:00This device is a silicon crystal receiver.
0:37:00 > 0:37:03There's a tiny tungsten wire coiled down
0:37:03 > 0:37:07and touching the surface of a little silicon crystal.
0:37:07 > 0:37:10It's incredible how important a device it was.
0:37:14 > 0:37:20It was the first time silicon had really been exploited as a semi-conductor,
0:37:20 > 0:37:24but for it to work, it needed to be very pure
0:37:24 > 0:37:29and both sides in the war put a lot of resources into purifying it.
0:37:31 > 0:37:34In fact, the British had better silicon devices
0:37:34 > 0:37:39so they must have had some coils of silicon already at that time
0:37:39 > 0:37:43which we were just starting with, you know, in Berlin.
0:37:45 > 0:37:48The British had better silicon semi-conductors
0:37:48 > 0:37:52because they had help from laboratories in the US,
0:37:52 > 0:37:54in particular, the famous Bell Labs.
0:37:54 > 0:37:58And it wasn't long before physicists realised
0:37:58 > 0:38:01that if semi-conductors could replace valves in radar,
0:38:01 > 0:38:07perhaps they could replace valves in other devices too, like amplifiers.
0:38:09 > 0:38:14The simple vacuum tube, with its one-way stream of electrons,
0:38:14 > 0:38:17had been modified to produce a new device.
0:38:17 > 0:38:21By placing a metal grill in the path of the electrons
0:38:21 > 0:38:22and applying a tiny voltage to it,
0:38:22 > 0:38:26a dramatic change in the strength of the beam could be produced.
0:38:26 > 0:38:29These valves worked as amplifiers,
0:38:29 > 0:38:33turning a very weak electrical signal into a much stronger one.
0:38:33 > 0:38:37An amplifier is something, in one sense, really simple.
0:38:37 > 0:38:41You just take a small current, you turn it into a larger current.
0:38:41 > 0:38:44But in other ways, it changes the world,
0:38:44 > 0:38:49because when you can amplify a signal, you can send it anywhere in the world.
0:38:52 > 0:38:57As soon as the war was over, German expert Herbert Matare
0:38:57 > 0:39:00and his colleague, Heinrich Welker, started to build
0:39:00 > 0:39:05a semi-conductor device that could be used as an electrical amplifier.
0:39:06 > 0:39:13And here is that first working model that Matare and Welker made.
0:39:13 > 0:39:16If you look inside, you can see the tiny crystal
0:39:16 > 0:39:20and the wires that make contact with it.
0:39:20 > 0:39:23If you pass a small current through one of the wires,
0:39:23 > 0:39:27this allows a much larger current to flow through the other one,
0:39:27 > 0:39:31so it was acting as a signal amplifier.
0:39:33 > 0:39:38These tiny devices could replace big, expensive valves
0:39:38 > 0:39:44in long distance telephone networks, radios and other equipment
0:39:44 > 0:39:47where a faint signal needed boosting.
0:39:47 > 0:39:50Matare immediately realised what he'd created,
0:39:50 > 0:39:53but his bosses were initially not interested.
0:39:53 > 0:39:56Not, that is, until a paper appeared in a journal
0:39:56 > 0:39:59announcing a Bell Labs discovery.
0:40:03 > 0:40:07A research team there had stumbled across the same effect
0:40:07 > 0:40:11and now they were announcing their invention to the world.
0:40:11 > 0:40:13They called it the transistor.
0:40:15 > 0:40:20They had it in December 1947, and we had it in beginning '48.
0:40:20 > 0:40:24But just, just life, you know.
0:40:24 > 0:40:28They had it a little bit earlier, the effect.
0:40:28 > 0:40:33But, funnily enough, their transistors were just no good.
0:40:35 > 0:40:38Although the European device was more reliable
0:40:38 > 0:40:41than Bell Labs' more experimental model,
0:40:41 > 0:40:44neither quite fulfilled their promise -
0:40:44 > 0:40:47they worked, but were just too delicate.
0:40:49 > 0:40:53So the search was on for a more robust way to amplify electrical signals
0:40:53 > 0:40:57and the breakthrough came by accident.
0:40:58 > 0:41:02In Bell Labs, silicon crystal expert Russell Ohl
0:41:02 > 0:41:06noticed that one of his silicon ingots had a really bizarre property.
0:41:06 > 0:41:10It seemed to be able to generate its own voltage
0:41:10 > 0:41:14and when he tried to measure this by hooking it up to an Oscilloscope,
0:41:14 > 0:41:18he noticed that the voltage changed all the time.
0:41:18 > 0:41:21The amount of voltage it generated seemed to depend on
0:41:21 > 0:41:24how much light there was in the room.
0:41:24 > 0:41:28So, by casting a shadow over the crystal,
0:41:28 > 0:41:30he saw the voltage dropped.
0:41:30 > 0:41:33More light meant the voltage went up.
0:41:33 > 0:41:40What's more, when he turned a fan on between the lamp and the crystal
0:41:40 > 0:41:44the voltage started to oscillate with the same frequency
0:41:44 > 0:41:49that the blades of the fan were casting shadows over the crystal.
0:41:52 > 0:41:56One of Ohl's colleagues immediately realised
0:41:56 > 0:42:00that the ingot had a crack in it that formed a natural junction,
0:42:00 > 0:42:05and this tiny natural junction in an otherwise solid block
0:42:05 > 0:42:09was acting just like the much more delicate junction
0:42:09 > 0:42:14between the end of a wire and a crystal that Bose had discovered.
0:42:14 > 0:42:16Except here, it was sensitive to light.
0:42:18 > 0:42:23The ingot had cracked because either side contained
0:42:23 > 0:42:27slightly different amounts of impurities.
0:42:27 > 0:42:30One side had slightly more of the element phosphorous,
0:42:30 > 0:42:35while the other had slightly more of a different impurity - boron.
0:42:35 > 0:42:38And electrons seemed to be able to move across
0:42:38 > 0:42:43from the phosphorous side to the boron side, but not vice versa.
0:42:43 > 0:42:46Photons of light shining down onto the crystal
0:42:46 > 0:42:49were knocking electrons out of the atoms,
0:42:49 > 0:42:53but it was the impurity atoms that were driving this flow.
0:42:55 > 0:42:59Phosphorous has an electron that is going spare...
0:42:59 > 0:43:02and boron is keen to accept another,
0:43:02 > 0:43:06so electrons tended to flow from the phosphorous side
0:43:06 > 0:43:12to the boron side and, crucially, only flowed one way across the junction.
0:43:19 > 0:43:22The head of the semi-conductor team, William Shockley,
0:43:22 > 0:43:26saw the potential of this one-way junction within a crystal,
0:43:26 > 0:43:30but how would it be possible to create a crystal
0:43:30 > 0:43:34with two junctions in it that could be used as an amplifier?
0:43:36 > 0:43:39Another researcher at Bell Labs called Gordon Teal
0:43:39 > 0:43:43had been working on a technique that would allow just that.
0:43:45 > 0:43:49He'd discovered a special way to grow single crystals
0:43:49 > 0:43:52of the semi-conductor germanium.
0:43:55 > 0:43:58In this research institute, they grow semi-conductor crystals
0:43:58 > 0:44:02in the same way that Teal did back in Bell Labs -
0:44:02 > 0:44:05only here, they grow them much, much bigger.
0:44:10 > 0:44:15At the bottom of this vat is a container with glowing hot,
0:44:15 > 0:44:18molten germanium, just as pure as you can get it.
0:44:18 > 0:44:24Inside it are a few atoms of whatever impurity is required
0:44:24 > 0:44:27to alter its conductive properties.
0:44:27 > 0:44:32Now, the rotating arm above has a seed crystal at the bottom
0:44:32 > 0:44:37that has been dipped into the liquid and will be slowly raised up again.
0:44:42 > 0:44:47As the germanium cools and hardens, it forms a long crystal
0:44:47 > 0:44:49like an icicle, below the seed.
0:44:49 > 0:44:54The whole length is one single, beautiful germanium crystal.
0:45:02 > 0:45:05Teal worked out that, as the crystal is growing,
0:45:05 > 0:45:10other impurities can be added to the vat and mixed in.
0:45:10 > 0:45:16This gives us a single crystal with thin layers of different impurities
0:45:16 > 0:45:20creating junctions within the crystal.
0:45:27 > 0:45:31This crystal with two junctions in it was Shockley's dream.
0:45:31 > 0:45:36Applying a small current through the very thin middle section
0:45:36 > 0:45:41allows a much larger current to flow through the whole triple sandwich.
0:45:44 > 0:45:47From a single crystal like this,
0:45:47 > 0:45:51hundreds of tiny solid blocks could be cut,
0:45:51 > 0:45:56each containing the two junctions that would allow the movement of electrons through them
0:45:56 > 0:45:58to be precisely controlled.
0:46:01 > 0:46:04These tiny and reliable devices
0:46:04 > 0:46:08could be used in all sorts of electrical equipment.
0:46:08 > 0:46:13You cannot have the electronic equipment that we have without tiny components.
0:46:13 > 0:46:16And you get a weird effect - the smaller they get, the more reliable they get,
0:46:16 > 0:46:18it's a win-win situation.
0:46:18 > 0:46:19APPLAUSE
0:46:20 > 0:46:26The Bell Labs team were awarded the Nobel Prize for their world changing invention,
0:46:26 > 0:46:30while the European team were forgotten.
0:46:34 > 0:46:36William Shockley left Bell Labs,
0:46:36 > 0:46:42and in 1955 set up his own semi-conductor Laboratory in rural California,
0:46:42 > 0:46:47recruiting the country's best physics graduates.
0:46:47 > 0:46:49But the celebratory mood didn't last long,
0:46:49 > 0:46:54because Shockley was almost impossible to work for.
0:46:54 > 0:46:59People left his company because they just disliked the way he treated them.
0:46:59 > 0:47:04So, the fact that Shockley was actually such a git
0:47:04 > 0:47:07is why you have Silicon Valley.
0:47:07 > 0:47:12It starts that whole process of spin-off and growth and new companies,
0:47:12 > 0:47:17and it all starts off with Shockley being such a shocking human being.
0:47:28 > 0:47:30The new companies were in competition with each other
0:47:30 > 0:47:34to come up with the latest semi-conductor devices.
0:47:34 > 0:47:36They made transistors so small
0:47:36 > 0:47:41that huge numbers of them could be incorporated into an electrical circuit
0:47:41 > 0:47:45printed on a single slice of semi-conductor crystal.
0:47:49 > 0:47:55These tiny and reliable chips could be used in all sorts of electrical equipment...
0:47:55 > 0:47:58most famously in computers.
0:47:58 > 0:48:01A new age had dawned.
0:48:11 > 0:48:14Today, microchips are everywhere.
0:48:14 > 0:48:18They've transformed almost every aspect of modern life,
0:48:18 > 0:48:22from communication to transport and entertainment.
0:48:23 > 0:48:25But, perhaps, just as importantly,
0:48:25 > 0:48:28our computers have become so powerful
0:48:28 > 0:48:33they're helping us to understand the universe in all its complexity.
0:48:36 > 0:48:40A single microchip like this one today
0:48:40 > 0:48:45can contain around four billion transistors.
0:48:45 > 0:48:49It's incredible how far technology has come in 60 years.
0:48:53 > 0:48:56It's easy to think that with the great leaps we've made
0:48:56 > 0:48:58in understanding and exploiting electricity,
0:48:58 > 0:49:02there's little left to learn about it.
0:49:02 > 0:49:04But we'd be wrong.
0:49:06 > 0:49:10For instance, making the circuits smaller and smaller
0:49:10 > 0:49:16meant that a particular feature of electricity that had been known about for over a century
0:49:16 > 0:49:19was becoming more and more problematic.
0:49:19 > 0:49:20Resistance.
0:49:23 > 0:49:27A computer chip has to be continuously cooled.
0:49:27 > 0:49:29If you take away the fan, this is what happens.
0:49:33 > 0:49:34Wow! That's shooting up!
0:49:34 > 0:49:37100, 120, 130 degrees...
0:49:42 > 0:49:46..200 degrees, and it cut out.
0:49:46 > 0:49:50That just took a few seconds and the chip is well and truly cooked.
0:49:50 > 0:49:54You see, as the electrons flow through the chip,
0:49:54 > 0:49:56they're not just travelling around unimpeded.
0:49:56 > 0:49:59They're bumping into the atoms of silicone,
0:49:59 > 0:50:04and the energy being lost by these electrons is producing heat.
0:50:05 > 0:50:07Now, sometimes this was useful.
0:50:07 > 0:50:11Inventors made electric heaters and ovens,
0:50:11 > 0:50:13and whenever they got something to glow white-hot,
0:50:13 > 0:50:15well, that's a light bulb.
0:50:15 > 0:50:18But resistance in electronic apparatus,
0:50:18 > 0:50:20and in power lines,
0:50:20 > 0:50:21is the major waste of energy
0:50:21 > 0:50:24and a huge problem.
0:50:29 > 0:50:35It's thought that resistance wastes up to 20% of all the electricity we generate.
0:50:35 > 0:50:40It's one of the greatest problems of modern times.
0:50:40 > 0:50:45And the search is on for a way to solve the problem of resistance.
0:50:50 > 0:50:52What we think of as temperature
0:50:52 > 0:50:58is really a measure of how much the atoms in a material are vibrating.
0:50:58 > 0:51:00And if the atoms are vibrating,
0:51:00 > 0:51:02then electrons flowing through
0:51:02 > 0:51:05are more likely to bump into them.
0:51:05 > 0:51:07So, in general, the hotter the material,
0:51:07 > 0:51:10the higher its electrical resistance,
0:51:10 > 0:51:11and the cooler it is,
0:51:11 > 0:51:13the lower the resistance.
0:51:13 > 0:51:15But what happens if you cool something right down,
0:51:15 > 0:51:18close to absolute zero,
0:51:18 > 0:51:22-273 degrees Celsius?
0:51:22 > 0:51:24Well, at absolute zero,
0:51:24 > 0:51:26there's no heat at all,
0:51:26 > 0:51:29and so the atoms aren't moving at all.
0:51:29 > 0:51:32What happens then to the flow of electricity?
0:51:32 > 0:51:34The flow of electrons?
0:51:37 > 0:51:42Using a special device called a cryostat,
0:51:42 > 0:51:45that can keep things close to absolute zero, we can find out.
0:51:45 > 0:51:49Inside this cryostat,
0:51:49 > 0:51:50in this coil, is mercury,
0:51:50 > 0:51:52the famous liquid metal.
0:51:52 > 0:51:55And it forms part of an electric circuit.
0:51:55 > 0:51:59Now, this equipment here measures the resistance in the mercury,
0:51:59 > 0:52:02but look what happens as I lower the mercury
0:52:02 > 0:52:06into the coldest part of the cryostat.
0:52:09 > 0:52:11There it is.
0:52:11 > 0:52:13The resistance has dropped to absolutely nothing.
0:52:13 > 0:52:16Mercury, like many substances we now know,
0:52:16 > 0:52:18have this property.
0:52:18 > 0:52:20It's called "becoming super conducting",
0:52:20 > 0:52:25which means they have no resistance at all to the flow of electricity.
0:52:26 > 0:52:29But these materials only work
0:52:29 > 0:52:32when they're very, very cold.
0:52:32 > 0:52:37If we could use a superconducting material in our power cables,
0:52:37 > 0:52:39and in our electronic apparatus,
0:52:39 > 0:52:44we'd avoid losing so much of our precious electrical energy through resistance.
0:52:47 > 0:52:51The problem, of course, is that superconductors had to be kept
0:52:51 > 0:52:54at extremely low temperatures.
0:52:54 > 0:52:57Then, in 1986,
0:52:57 > 0:52:58a breakthrough was made.
0:53:01 > 0:53:04In a small laboratory near Zurich, Switzerland,
0:53:04 > 0:53:09IBM physicists recently discovered superconductivity in a new class of materials
0:53:09 > 0:53:13that is being called one of the most important scientific breakthroughs in many decades.
0:53:15 > 0:53:21This is a block of the same material made by the researchers in Switzerland.
0:53:21 > 0:53:23It doesn't look very remarkable,
0:53:23 > 0:53:25but if you cool it down with liquid nitrogen,
0:53:25 > 0:53:28something special happens.
0:53:28 > 0:53:31It becomes a superconductor,
0:53:31 > 0:53:35and because electricity and magnetism are so tightly linked,
0:53:35 > 0:53:38that gives it equally extraordinary magnetic properties.
0:53:40 > 0:53:42This magnet is suspended,
0:53:42 > 0:53:45levitating above the superconductor.
0:53:47 > 0:53:51The exciting thing is, that although cold,
0:53:51 > 0:53:55this material is way above absolute zero.
0:54:05 > 0:54:08These magnetic fields are so strong
0:54:08 > 0:54:12that not only can they support the weight of this magnet,
0:54:12 > 0:54:14but they should also support MY weight.
0:54:14 > 0:54:17I'm about to be levitated.
0:54:19 > 0:54:22Oh, it's a very, very strange sensation.
0:54:26 > 0:54:29When this material was first discovered in 1986,
0:54:29 > 0:54:31it created a revolution.
0:54:31 > 0:54:35Not only had no-one considered that it might be superconducting,
0:54:35 > 0:54:41but it was doing so at a temperature much warmer than anyone had thought possible.
0:54:41 > 0:54:45We are tantalisingly close to getting room temperature superconductors.
0:54:45 > 0:54:46We're not there yet,
0:54:46 > 0:54:49but one day, a new material will be found.
0:54:49 > 0:54:52And when we put that into our electronics equipment,
0:54:52 > 0:54:56we could build a cheaper, better, more sustainable world.
0:54:58 > 0:55:02Today, materials have been produced that exhibit this phenomenon
0:55:02 > 0:55:06at the sort of temperatures you get in your freezer.
0:55:06 > 0:55:11But these new superconductors can't be fully explained by the theoreticians.
0:55:11 > 0:55:13So without a complete understanding,
0:55:13 > 0:55:17experimentalists are often guided as much by luck
0:55:17 > 0:55:20as they are by a proper scientific understanding.
0:55:22 > 0:55:25Recently, a laboratory in Japan held a party
0:55:25 > 0:55:28in which they ended up dosing their superconductors
0:55:28 > 0:55:30with a range of alcoholic beverages.
0:55:31 > 0:55:34Unexpectedly, they found that red wine
0:55:34 > 0:55:38improves the performance of the superconductors.
0:55:40 > 0:55:42Electrical research
0:55:42 > 0:55:45now has the potential, once again,
0:55:45 > 0:55:47to revolutionise our world,
0:55:47 > 0:55:51IF room temperature superconductors can be found.
0:56:02 > 0:56:06Our addiction to electricity's power is only increasing.
0:56:06 > 0:56:11And when we fully understand how to exploit superconductors,
0:56:11 > 0:56:14a new electrical world will be upon us.
0:56:14 > 0:56:20It's going to lead to one of the most exciting periods of human discovery and invention,
0:56:20 > 0:56:24a brand-new set of tools, techniques and technologies
0:56:24 > 0:56:27to once again transform the world.
0:56:35 > 0:56:38Electricity has changed our world.
0:56:38 > 0:56:43Only a few hundred years ago, it was seen as a mysterious and magical wonder.
0:56:44 > 0:56:51Then, it leapt out of the laboratory with a series of strange and wondrous experiments,
0:56:51 > 0:56:54eventually being captured and put to use.
0:56:56 > 0:56:58It revolutionised communication,
0:56:58 > 0:57:00first through cables,
0:57:00 > 0:57:04and then as waves through electricity's far-reaching fields.
0:57:06 > 0:57:09It powers and lights the modern world.
0:57:09 > 0:57:13Today, we can hardly imagine life without electricity.
0:57:13 > 0:57:15It defines our era,
0:57:15 > 0:57:18and we'd be utterly lost without it.
0:57:21 > 0:57:23And yet, it still offers us more.
0:57:23 > 0:57:28We stand, once again, at the beginning of a new age of discovery,
0:57:28 > 0:57:29a new revolution.
0:57:36 > 0:57:38But above all else,
0:57:38 > 0:57:43there's one thing that all those who deal in the science of electricity know -
0:57:43 > 0:57:46its story is not over yet.
0:58:05 > 0:58:08To find out more about the story of electricity,
0:58:08 > 0:58:11and to put your power knowledge to the test,
0:58:11 > 0:58:15try the Open University's interactive energy game.
0:58:15 > 0:58:20Go to:
0:58:20 > 0:58:22..and follow links to the Open University.
0:58:44 > 0:58:47Subtitles by Red Bee Media Ltd
0:58:47 > 0:58:51E-mail subtitling@bbc.co.uk