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00:00On the 14th of August, 1894, an excited crowd were outside the doors of the Oxford Natural History Museum.
00:18This huge Gothic building was hosting the annual meeting of the British Association for the Advancement of Science.
00:28Over 2,000 tickets had been sold in advance,
00:31and the museum was fully packed, waiting for the next door to be given by Professor Oliver Lodge.
00:41His name may seem strange to us today,
00:44but his discoveries would be at the level of other great pioneers of electricity,
00:50such as Benjamin Franklin,
00:54Alessandro Volta,
00:57or even the brilliant Michael Faraday.
01:01Quite unwittingly, we would see the direct cause of a series of events
01:05that would revolutionise the use of brass and telegraph wire in the Victorian world.
01:11This lecture would mark the birth of the modern electrical world,
01:15a world dominated by silicon and mass-wired communication.
01:21In this programme, we will discover how electricity brought the world together
01:26through the media and computer networks.
01:31We will see how humanity learned to unravel the mysteries of electricity
01:36and exploit it at the atomic level.
01:39After centuries of experiments,
01:41man would be able to fully understand the behaviour of electricity.
01:45We are at the birth of a new world,
01:48a world of electricity.
01:50We are at the birth of a new era.
01:56The History of Electricity
02:01Episode 3 Light and Energy
02:0519th century
02:16These fluorescent lights are not connected to any source of energy,
02:21but they are lit.
02:23It is the invisible effect of electricity,
02:26an effect that is not limited to the cables through which the current circulates.
02:31In the mid-19th century,
02:33the theory that justifies this phenomenon was proposed.
02:40The theory says that there is a field of force
02:43around all matter charged with electrical energy.
02:47These fluorescent tubes are lit
02:50because they are under the influence of the field of force
02:53generated by the high-voltage cables that I have above me.
03:01Michael Faraday would be the first to say
03:04that any flow of electricity creates a kind of invisible field of force.
03:11However, it would be a brilliant young Scottish man
03:14named James Clare Maxwell
03:16who would later prove Faraday's theory
03:19using mathematics, not experimentation.
03:24His theory was far cry from the typical mindset
03:28of understanding how the world works,
03:31which was essentially to see it as a physical machine.
03:44Before Maxwell, scientists would have designed strange machines
03:48and carried out experiments to create and measure electricity.
03:53However, Maxwell was interested in numbers
03:56and not only was he able to demonstrate
03:59that there was an invisible field of force in electricity,
04:02but he also observed how it could be manipulated.
04:05He would be able to make his theory
04:08one of the most important discoveries in history.
04:13Maxwell was a mathematician and a very good one.
04:16He revolutionized the perception of electricity and magnetism
04:19by expressing them all in mathematical equations.
04:22The most important fact is that in Maxwell's equations
04:25there is a link between electricity and magnetism,
04:28as well as the fact that electricity is transmitted by waves.
04:43Maxwell's calculations showed how these fields could disturb
04:47rather than touching the surface of the water
04:50by introducing a finger,
04:52changing the direction of the electric current
04:55would create a wave in both fields, magnetic and electric.
05:01And constantly changing the direction of the current alternatively,
05:05forward and backward,
05:08would produce a whole series of waves,
05:12waves that would carry energy.
05:17Maxwell's maths was telling people
05:20that changing electric currents
05:23would be constantly sending off waves of energy
05:26into their surroundings, waves that would carry on forever,
05:29unless something absorbed them.
05:44Maxwell's mathematical theory was so novel and complicated
05:48that very few people of the time could understand it.
05:52Although his work was eminently theoretical,
05:55it would inspire a young German physicist called Heinrich Hertz.
06:01Hertz decided to focus his work on designing an experiment
06:05that could demonstrate Maxwell's wave theory.
06:11Look at this.
06:13This is Hertz's original apparatus.
06:17Its beauty lies in its simplicity.
06:21Heat generates an alternating current
06:24that flows through these metal rods,
06:27producing a spark between these two spheres.
06:30Now, if Maxwell's theory was correct,
06:33this alternating current should generate
06:36an invisible electromagnetic wave around the apparatus.
06:41If you place a wire in the path of that wave,
06:44then at the wire there should be a changing electromagnetic field,
06:49which would induce an electric current in the wire.
06:54So what Hertz did was to build this ring of wire,
06:58his receiver, which he could carry around
07:01in different sections of the room
07:04to see if he could detect the presence of the wave.
07:07And the way he did that was he put a mirror into the air
07:10in the wire across which a spark would jump.
07:13Now, because the current is so weak,
07:16that spark is very, very difficult to see.
07:19And Hertz had pretty much most of 1887
07:22in a dark room staring extensively through a lens
07:26to see if he could detect the presence of the faint spark.
07:43But Hertz was not alone in his company
07:46to recreate Maxwell's waves.
07:50In England, a young physicist named Oliver Lodge
07:53had been fascinated by the idea for years,
07:56but had not had the opportunity to design any experiment to demonstrate it.
08:04At the beginning of 1888,
08:06while preparing an experiment with lightning bolts,
08:09he would notice something strange.
08:14Lodge noticed that when he set up his equipment
08:18and sent an alternating current around the wires,
08:22he could see glowing patches between the wires.
08:26And with the facts we knew,
08:28he saw these glowing patches form a pattern.
08:32The sparks and electric sparks
08:35would happen along the wires.
08:39He observed that they corresponded with the crests and valleys of the waves
08:44of an invisible wave.
08:47Lodge had tested Maxwell's theory.
08:51Unknowingly, Lodge had recreated Maxwell's electromagnetic waves
08:56along the wires.
08:59The big question had been solved.
09:03Filled with excitement,
09:05Lodge was preparing to share his discovery with the world
09:08at the annual meeting of the British Association for the Advancement of Science.
09:15However, he decided to take a summer vacation first.
09:20Big mistake.
09:22In Germany, Heinrich Hertz was carrying out a parallel investigation
09:26to prove Maxwell's theory.
09:30Hertz would reach his goal
09:33by making his receiver create a tiny spark.
09:37And as he carried his receiver around the different passages of the room,
09:41he was able to map the shape of the waves produced by his apparatus.
09:46And he checked each one of Maxwell's calculations
09:50and tested them experimentally.
09:54It was a tour de force of experimental science.
10:06In England, with the crowd waiting for the meeting of the British Association
10:10for the Advancement of Science,
10:12Lodge returned from his vacation very relaxed and full of expectations.
10:18This, Lodge thought, was going to be the pinnacle of Lodge.
10:22He was going to announce his discovery of Maxwell's waves.
10:26His great friend, the mathematician Fitzgerald,
10:29was due to give the opening address of the meeting
10:32and in it he proclaimed that Heinrich Hertz
10:35had just published astounding results.
10:38He had detected Maxwell's waves traveling through space.
10:43We have snatched the lightning from Job himself
10:46and enslaved the all-powerful aether, he announced.
10:52Well, I can only imagine how Lodge felt
10:55when he saw his work exhausted.
11:00Professor Oliver Lodge had seen how his triumph
11:03was blurred under the shadow of Heinrich Hertz.
11:08Hertz had made a demonstration of his discovery
11:11of electromagnetic waves or, as it is known today, radio waves.
11:15It was unimaginable that his discovery
11:18would lead to a century of revolutions in communication.
11:27Maxwell's theory postulated that electric charges
11:30could generate a field of force
11:33and that the waves of this field could propagate like the waves in water.
11:41Hertz had built a device that could create
11:44and detect such waves when they traveled through water.
11:50Shortly after, another revelation would arrive
11:53that would take us one step further in the path of understanding electricity.
11:57A revelation that, again, would be related to Professor Oliver Lodge
12:01and that, once again, would be snatched from him.
12:12OXFORD
12:18The story begins in Oxford.
12:20It was the summer of 1894.
12:23At the beginning of the year, Hertz had died suddenly
12:27and Lodge was about to give a speech
12:30including a demonstration to spread the idea of waves to the public.
12:35Lodge had worked on his speech
12:38and had studied different ways of detecting waves
12:41and had borrowed new apparatus from his friends.
12:46He had managed to make significant improvements to the detection mechanisms.
12:52This bit of apparatus generates an alternating current
12:56and a spark across this gap.
13:00The alternating current, as Maxwell predicted,
13:03emits an electromagnetic wave that is picked up by this receptor
13:07producing a very weak electric current through these two antennas.
13:15This is what Hertz had done.
13:17Lodge's improvement of course was to set up a tube full of iron filings
13:22that, when receiving the weak electric current,
13:25passes through each other, closing a second electrical circuit
13:28that makes a bell sound.
13:34So if I push the button on this end,
13:37the bell at the receiver rings
13:39and it's doing that without any connection between the two apparatus.
13:43It's like magic.
13:52Imagine a packed house
13:54full of people in the audience
13:56and what they suddenly see is
13:58as if by magic, a bell ringing.
14:02It's quite incredible.
14:06It might not have been the most dramatic demonstration
14:09the audience had ever seen,
14:11but it certainly stimulated the sensation in the crowd.
14:15Lodge's apparatus, laid out like this,
14:18no longer looked like the science experiments it used to have.
14:21In fact, it looked remarkably similar to the telegraph
14:25that had revolutionised communication,
14:28but without those cables stretched between the sending and receiving stations.
14:35To the more working and savvy members of the audience,
14:38this was clearly more than showing that Maxwell was right.
14:43This was a new form of communication.
14:53Lodge would publish his notes on how to use his improvements
14:57to send and receive electromagnetic waves.
15:01Inventors, amateurs, enthusiasts and scientists all around the world
15:06would read Lodge's reports with excitement
15:09and began experimenting with the Hertzian waves.
15:15His words would inspire two renowned followers.
15:20Although of very different characteristics,
15:23both would improve the telegraph and go down in history
15:28with a greater reputation than his predecessor, Oliver Lodge.
15:31The first was Guglielmo Marconi.
15:35Marconi was a very intelligent, astute and charming individual.
15:39He definitely had the Italian Irish charm
15:42and he impressed almost anyone,
15:45from scientists to world renowned scientists.
15:50Marconi was not a scientist,
15:52but he had read everything he had come across
15:55to be able to build his own wireless telegraph.
16:00It is possible that the influence brought up in Bologna,
16:03very close to the Italian coast,
16:05that he saw the potential of wireless maritime communications
16:09fairly early on.
16:12At the early age of 22,
16:14he would travel to London with his Irish mother as a presentation.
16:18The other person inspired by Lodge's work
16:21would be a professor at the Presidency College in Calcutta,
16:25called Jagadish Chandra Bose.
16:30Despite the titles at the Universities of London and Cambridge,
16:34the appointment of an Indian as a scientist in Calcutta
16:37had been for him a continuous struggle against racism and intolerance.
16:42It was said of the Indians that they did not have the temperament
16:46adequate for the rationality of science.
16:50Bose was determined to rebut that position
16:53and here the archivist, he just fell fast, he's set to work.
16:59This is a report of the 66th meeting
17:02of the British Association in Liverpool,
17:05September 1896.
17:07And here is Bose,
17:09first Indian ever to say at the Association meeting
17:13talking about his work and demonstrating his apparatus.
17:18He built and improved the detector that Lodge described
17:22because in the hot, sticky Indian climate
17:25he found that the metal filings
17:27that Lodge used to detect the waves
17:30became rusty and stuck together.
17:33So Bose had to develop a more practical detector
17:36using a coil wire instead.
17:39His work was described as a sensation.
17:44The detector turned out to be much more reliable
17:47and could be boarded on ships
17:49increasing the potential of the British fleet.
17:53Great Britain was the center of a huge network of telecommunications
17:57that reached almost all over the world.
18:01This technology would be used in commercial ships
18:04and military ships,
18:06becoming a key piece of the British Empire.
18:10But Bose, a pure scientist,
18:12was not interested in commercial applications
18:15of wireless signals,
18:17unlike Marconi.
18:20A new field of research had opened up,
18:23but Marconi was not a scientist,
18:25so he had a very different point of view.
18:29Perhaps this was the main reason for his success.
18:33He had a special ability
18:35to contact the right person
18:37at the right time.
18:42Marconi used his contacts
18:44to go directly to the source of the resources he needed.
18:53The British Post Office was a huge and powerful institution
18:56when Marconi first arrived in London in 1896.
19:01These buildings had just been inaugurated
19:03and were already being used
19:05for the Empire's postal and telegraphic services.
19:10Marconi had come from Italy
19:12claiming that he could send wireless messages
19:15with a range never seen before.
19:18And the head of postal engineering,
19:20William Preece,
19:22immediately saw the potential of the technology.
19:27Preece offered Marconi
19:29both financial and engineering resources
19:32of the Post Office,
19:34and soon the tests would begin from above.
19:39The old headquarters of the Post Office
19:41was right there.
19:44Between this roof and that one,
19:46Marconi and the Post Office engineers
19:48would send and receive electromagnetic waves.
19:52The engineers helped improve the apparatus,
19:55and then Preece and Marconi together
19:57demonstrated it in influential people
19:59in government and the Navy.
20:05What Preece didn't realize
20:07was that even as he proudly announced
20:09Marconi's successful collaboration
20:11with the Post Office,
20:13this orchestrated a plan behind the scenes.
20:18The inventor had applied for the patent
20:20for the wireless telegraphy
20:22and was planning on setting up
20:24his own telegraph company.
20:27When the patent was granted,
20:29all hell broke loose for the scientific community.
20:35The patent was revolutionary in itself.
20:43It's impossible to patent elements
20:45that are of public domain,
20:47but the only public here
20:49was that Marconi had developed
20:51his equipment inside a box.
20:57When the patent was granted,
20:59Marconi would ceremoniously open the box
21:02so that everyone could see
21:04the inventions that lay within.
21:14A circuit of batteries,
21:16which, when closed with iron filings,
21:18would make a bell ring.
21:21Nothing they hadn't seen before.
21:24But Marconi had patented the whole thing.
21:29Marconi didn't become famous
21:31for inventing the radio.
21:33He didn't invent it.
21:35He improved it and turned it into a system.
21:38Lodge didn't do it.
21:40That's why it's not his name that's remembered,
21:42but Marconi's.
21:49The scientific world was at war.
21:52A young man had arrived
21:54who knew little about science
21:56and was about to make his fortune
21:58at the cost of his work.
22:01Even his great supporter, Priest,
22:03was disappointed and hurt
22:05when he found out that Marconi
22:07was going to go and set up his own company.
22:10Lodge, as well as other scientists,
22:12began a frenzy of patenting
22:14in every tiny detail
22:16of the food they made to their equipment.
22:23This frenetic atmosphere
22:25impressed Bose when he returned to England.
22:28In a letter he wrote to India,
22:30he discussed what he would perceive
22:32when he arrived.
22:33Money, money, more money.
22:35What a devouring animal.
22:37I wish you could see
22:39the crazy amount of people
22:41who are here for the money.
22:43His disillusionment
22:45when he returned to the country
22:47he knew as an example
22:49of scientific integrity and excellence
22:51is palpable.
22:53Eventually, though,
22:55it was his friend's
22:57who would convince him
22:59to patent his one and only discovery,
23:01a new kind of wave detector.
23:05It was this discovery
23:07that would have caused
23:09a much greater world revolution.
23:11He had discovered
23:13the power of crystals.
23:17This would replace
23:19the old techniques
23:21based on worn iron files.
23:23It would be the key
23:25to the detection of waves
23:27and the core of the new radio industry.
23:31Bose's discovery was simple,
23:33but it would shape
23:35modern society.
23:37When some crystals
23:39come in contact with metals
23:41to test their conductivity,
23:43they can show rather odd
23:45and fair behavior.
23:47Take this crystal, for example.
23:49If I can touch it
23:51exactly in the right spot
23:53and then hook it up
23:55to a battery,
23:57it gives quite a significant
23:59power.
24:01But if I switch around
24:03and give this a battery
24:05and try and pass the current
24:07through any opposite direction,
24:09it's a lot less.
24:13It's a semiconductor material
24:15of electricity
24:17and is the first application
24:19in the detection
24:21of electromagnetic waves.
24:25When Bose used a crystal
24:27like this in a circuit
24:29to detect iron files,
24:31he found it was a much more
24:33efficient detector
24:35of electromagnetic waves.
24:37It was this strange property
24:39of the junction
24:41between the wire,
24:43known as the trans-whisker,
24:45and the crystal
24:47which allowed currents to pass
24:49that meant it could be used
24:51to extract a signal
24:53for electromagnetic waves.
25:13With crystals as detectors,
25:15now it was possible
25:17to broadcast and detect
25:19the actual sound
25:21of a human voice
25:23or music.
25:47The scientific discoveries
25:49in which he had taken part
25:51had great commercial potential.
25:53The only patent he had
25:55managed to secure,
25:57the technique to adjust
25:59the receiver in search
26:01of a particular radio signal,
26:03was bought by
26:05the gigantic company
26:07of Marconi.
26:11Perhaps the worst
26:13indignation would come
26:15when Marconi was awarded
26:17the Nobel Prize in Physics
26:19for wireless communication.
26:21It's difficult to imagine
26:23a figure so large
26:25to the physicist who so narrowly
26:27missed out to Hertz
26:29in the discovery of radio waves
26:31and who then got to show the world
26:33that they could send and receive signals.
26:37However, as we will see
26:39in the next video,
26:41Lodge would continue
26:43to use magnanimously
26:45the technology he had developed
26:47as an instrument to give credit
26:49to others.
27:13Today we can hardly imagine a world
27:15without broadcasters.
27:17Imagine a time
27:19when radio waves
27:21had to be transmitted.
27:43It was the triumph of pure science.
27:45From Maxwell to Lodge
27:47and through Hertz.
27:49However, the very nature
27:51of electricity itself
27:53remained a mystery.
27:55What was the real cause
27:57of the production of these
27:59electric charges and currents?
28:01Scientists were learning
28:03how to exploit it,
28:05but they still didn't know
28:07what exactly electricity was.
28:09This enigma would be
28:11later solved through
28:13the observation of the flow
28:15of electricity in the different materials.
28:17Let's go back in the 1850s,
28:19in the middle of the 19th century,
28:21to study Heinrich Geisler,
28:23the great glassblower
28:25and researcher
28:27who made these beautiful showcases.
28:37Geisler extracted
28:39most of the air
28:41from these tubes
28:43and then introduced
28:45small gas mixtures.
28:49By making electricity
28:51circulate,
28:53he managed to illuminate
28:55them by showing
28:57amazing colors
28:59and making the electric flow
29:01seem tangible.
29:03Although at first
29:05they were designed
29:07for 50 years,
29:09their model would be used
29:11to study the flow of electricity.
29:15The following works
29:17were aimed at extracting
29:19more and more air
29:21to see if the electric current
29:23could circulate in the vacuum.
29:29This is one of the few
29:31graphical proofs
29:33by the British scientist
29:35who could find a vacuum
29:37good enough to answer that question.
29:39His name was William Crookes.
29:43Crookes created tubes
29:45like this and he pumped out
29:47as much air as he could
29:49so they were as close
29:51to an absolute vacuum as he could make it.
29:53Then, when he passed
29:55an electric current through the tube,
29:59he noticed right below
30:01the far end
30:03a beam seemed shining
30:05through the tube
30:07and hitting the glass on the other end.
30:09He saw that at last we could see
30:11at least the beam that we know
30:13as a cathode ray.
30:15This tube was the forerunner
30:17of the cathode ray tube
30:19that was used in television sets
30:21for decades.
30:27The physicist
30:29J. J. Thomson
30:31discovered that the cathode rays
30:33were composed of small particles
30:35charged negatively.
30:37As their function was
30:39the transport of electricity,
30:41they were called electrons.
30:43Because the electrons
30:45only move one direction
30:47from the positive charge plate
30:49to the other end,
30:51they behaved exactly the same way
30:53as most semiconductor crystals.
30:57But where as most crystals
30:59had to find a spot
31:01for them to work,
31:03this tube could be
31:05manufactured systematically.
31:07They became known as valves
31:09and they soon replaced
31:11themselves with radio-sensitive
31:13electrodes.
31:17Again, these discoveries
31:19would lead to a technological explosion.
31:23Early 20th century,
31:25the limit of electronics
31:27depended on the versatility
31:29of the valves.
31:31The radio manufacturers
31:33worked with valves,
31:35the TV manufacturers
31:37also, and the computers.
31:39These elements are the
31:41pillars of electronics.
31:43Once the scientists
31:45had discovered how to manipulate
31:47the flow of electrons
31:49through the vacuum,
31:51the next step would be
31:53to discover their circulation
31:55through the pieces that make up
31:57the materials,
31:59the atoms.
32:09At the beginning of the 20th century,
32:11humanity began to reveal
32:13the nature and behavior
32:15of atoms.
32:17Electricity began to be studied
32:19at the atomic level.
32:25At the University of Manchester,
32:27Ernest Rutherford's team
32:29studied the internal structure
32:31of the atom and developed
32:33an atomic map.
32:35This revelation
32:37would clarify some of the
32:39most enigmatic concepts
32:41of electricity.
32:43In 1913,
32:45the atomic model proposed
32:47a positively charged nucleus
32:49surrounded by negative charged
32:51electrons orbiting
32:53the atomic crust following
32:55a pattern.
32:57Each of these shells
32:59corresponds to an electron
33:01with a particular energy.
33:03Now, given an energy increase,
33:05an electron could jump
33:07from an inner shell to an outer one
33:09and the energy had to be
33:11jumped to balance.
33:13If not enough, the electron
33:15wasn't stable enough
33:17and it was often temporary
33:19because the electron could drop
33:21and the electron could return
33:23to its initial orbit.
33:25If it did so, a photon
33:27and energy would be released.
33:29The amount of energy released
33:31would depend on the wavelength
33:33or, as we perceive it,
33:35its color.
33:41Understanding the structure
33:43of the atom would explain
33:45the great luminescent spectacles
33:47of nature.
33:49As in the Geisler tubes,
33:51the type of gas through which
33:53electricity circulates defines
33:55the color of the resulting light.
33:59The bluish tones of the rays
34:01derive from the nitrogen composition
34:03of the atmosphere.
34:05The highest layers
34:07of the atmosphere have
34:09a different gas composition,
34:11so the detached photons
34:13create spectacular rings
34:15of different colors.
34:19The knowledge of atoms
34:21and how they link
34:23to create matter,
34:25as well as the behavior
34:27of electrons,
34:29would be the last piece
34:31to understand the fundamental
34:33nature of electricity.
34:39This is the Winsworth machine
34:41and it's used to generate
34:43electric charges.
34:46The friction releases
34:48the electrons from the disks
34:50that run through the metal arms
34:52of the machine.
34:56Metals have conductive properties
34:58because their electrons
35:00have weak links
35:02within the atomic structure,
35:04so it's easy to shake them
35:06and make them flow like electricity.
35:08Insulators, on the other hand,
35:10don't conduct electricity
35:12because their atomic structure
35:14is firm, so their electrons
35:16can't move.
35:18Understanding the flow
35:20of electrons, and hence
35:22electricity, seemed to explain
35:24the phenomenon of conductivity.
35:26However,
35:28how to explain
35:30the peculiar properties
35:32of semiconductors?
35:36Our technological society
35:38is based on semiconductors.
35:40Without them,
35:42the world would fall.
35:44Jagadish Chandra Bose
35:46would stumble with semiconductors
35:48at the end of the 19th century.
35:50But no one could have guessed
35:52the importance
35:54they would have today.
35:56With the outbreak
35:58of World War II,
36:00things were going to change.
36:06Here in Oxford,
36:08this new laboratory
36:10became a military hub
36:12for war research.
36:14The researchers were tasked
36:16with improving
36:18the British radar system.
36:24The radar is a system
36:26that uses electromagnetic waves
36:28to detect enemy aircraft.
36:30The more reliable it was,
36:32the more likely it was
36:34that the valve system
36:36wasn't up to the task.
36:40So the team had to turn
36:42to old technology,
36:44set valves and then use
36:46silicon crystals.
36:48Now, they didn't use
36:50the same sort of crystals
36:52that Bose had developed,
36:54they used silicon.
36:56This device
36:58is a silicon crystal receiver.
37:00There's a tiny tungsten wire
37:02that pulls down,
37:04touching the surface
37:06of a little silicon crystal.
37:08It's incredible how important
37:10a device can be.
37:16It was the first time
37:18silicon was used as a semiconductor.
37:20However, the imperious need
37:22for crystal purity
37:24required many of the resources
37:26on both sides to be
37:28used for this purpose.
37:32In fact, the British
37:34had better silicon devices,
37:36so they would have
37:38developed the coils
37:40for when we started
37:42to investigate in Berlin.
37:46The British had better
37:48semiconductors because
37:50they had received help
37:52from US laboratories,
37:54especially from the famous
37:56Bell Labs.
37:58The physicists realized
38:00that if the device worked
38:02on radars,
38:04as well as amplifiers,
38:10modifying the vacuum tube
38:12with its simple electron route,
38:14a new device was created.
38:18Interposing a metal grill
38:20with a small voltage
38:22in the path of the electrons,
38:24an exponential change
38:26was achieved in the power
38:28of the produced light beam.
38:30The resulting valves
38:32produced too much shielding.
38:34On the one hand,
38:36an amplifier would be defined
38:38as a simple device that allows
38:40to convert a small current
38:42into a larger one.
38:44But on the other hand,
38:46it could be something
38:48that could change the world
38:50in such a way that it could
38:52amplify a signal anywhere
38:54in the world.
38:56At the end of the war,
38:58the German expert,
39:00Wolfgang Amadeus Mozart,
39:02began to build a semiconductor
39:04device to use it
39:06as an electric amplifier.
39:08This is the first model
39:10that was successfully developed
39:12by Matare and Belker.
39:14If you look inside,
39:16you can see the tiny crystal
39:18and the wires that make
39:20contact with it.
39:22If you pass a small current
39:24through one of the wires,
39:26this allows a much larger
39:28current to pass through
39:30the other end.
39:34These small pieces
39:36could replace the expensive
39:38valves of long-distance
39:40telephone networks,
39:42radios and any other device
39:44whose signal would need
39:46to be amplified.
39:48Matare would soon realize
39:50the importance of his discovery.
39:52However, his bosses
39:54did not consider it
39:56interesting.
39:58Until then, a newspaper
40:00announced the discovery
40:02of Bell Labs.
40:04A group of researchers
40:06would have come across
40:08the same effect,
40:10and so they announced
40:12the invention to the world.
40:14They called it the transistor.
40:16They had it in December 1947,
40:18and we had just started.
40:20Life is like that,
40:22no?
40:24They had it a little bit earlier,
40:26the effect.
40:28But, in any case,
40:30their transistors were
40:32just no good.
40:36Although the European model
40:38was more effective than the experimental
40:40developed at Bell Labs,
40:42neither met all the requirements.
40:44They worked,
40:46but they were very fragile.
40:50Then began the search
40:52for a more robust
40:54signal amplifier,
40:56a search that would end
40:58by accident.
41:00The silicon crystal expert
41:02at Bell Labs, Russell Hall,
41:04noticed that one of his silicon
41:06ingots had a really bizarre
41:08property.
41:10It seemed to generate
41:12its own voltage,
41:14and when he tried to measure it
41:16with an oscilloscope,
41:18the voltage changed all the time.
41:20Generally, it seemed to depend
41:22on how much light there was in the room.
41:24So, by casting a shadow
41:26over the crystal,
41:28he saw the voltage drop.
41:30More light than the voltage
41:32went out.
41:34What's more, when he turned
41:36a fan on, between
41:38the lamp and the crystal,
41:40the voltage started
41:42to oscillate
41:44the same frequency
41:46the blades of the fan
41:48went over the crystal.
42:19The ingot had cracked
42:21as either side contained
42:23slightly different acts
42:25of the impurities.
42:27One side had slightly more
42:29of the element of phosphorus
42:31than the other side
42:33had slightly more of the different
42:35elements of the boron.
42:37And the electrons seemed
42:39to be able to move across
42:41from the phosphorus side
42:43to the boron side,
42:45but not vice versa.
42:47The electrons out of the atoms
42:49of the silicon were transmitted
42:51through the impurities atoms.
42:56The atoms of phosphorus
42:58contained one more electron.
43:00The boron tends to capture electrons,
43:02so the electrons released
43:04tended to circulate
43:06through the crack
43:08always from the phosphorus side
43:10to the boron side,
43:12always in the same direction.
43:18The person in charge
43:20of the research group
43:22of semiconductors,
43:24William Shockley,
43:26saw the potential
43:28of this one-way path
43:30in the crystals
43:32and proposed the possibility
43:34of creating a crystal
43:36with two joints
43:38that could be used
43:40as an amplifier.
43:42Another researcher
43:44from the laboratory
43:46had discovered
43:48the way to cultivate crystals
43:50from the germanium semiconductor element.
43:56In this research institute
43:58they produce semiconductor crystals
44:00in the same way that Thiel
44:02would do it back in Bell Labs.
44:04The difference is that here
44:06they do it on a much larger scale.
44:10At the bottom of this vat
44:12is a container
44:14containing germanium,
44:16as pure as you can get it,
44:18just as pure as you can get it.
44:20Inside there are a few atoms
44:22of impurity,
44:24whatever impurity requires
44:26to alter its conductive properties.
44:28That rotating arm
44:30at the arm above
44:32has a seed crystal at the bottom
44:34that has been dipped into the liquid
44:36and will be slowly rising up again.
44:44As the germanium cools down
44:46and solidifies,
44:48a crystal is formed
44:50similar to a caramba under the crystal.
44:52In all its magnitude
44:54a crystal of precious germanium
44:56has been formed.
45:02Thiel discovered
45:04that impurities could be added
45:06to the container
45:08while the crystal was growing
45:10to mix with the mineral.
45:12The resulting crystal
45:14would have thin layers
45:16of the different impurities
45:18being created together
45:20throughout the entire crystal.
45:26This crystal
45:28was the crystal with two joints
45:30with which Shockley had dreamed.
45:32Applying a small current
45:34through the thin central section
45:36allows a much larger current
45:38to flow through the whole
45:40crystal.
45:46From each crystal like this
45:48small transversal blocks
45:50could be cut
45:52that would have the two together
45:54and allow precise control
45:56of the movement of the electrons
45:58through them.
46:02These small and reliable devices
46:04could be used
46:06in all kinds of electrical equipment.
46:10You can't have the electronic equipment
46:12without the tiny components.
46:14And you get a weird effect.
46:16The smaller they get,
46:18the more reliable they are.
46:20It's a win-win situation.
46:22Bell Labs would win the Nobel Prize
46:24for the invention that changed the world.
46:26The European team
46:28had been forgotten.
46:34In 1955
46:36William Shockley
46:38hired Bell Labs
46:40to open its own semiconductor
46:42materials laboratory
46:44in rural California.
46:46He hired the best physicists
46:48in the county.
46:50But the euphoria
46:52would not last long
46:54due to its difficult character.
46:56People left the company
46:58because they couldn't stand
47:00the way they were treated.
47:02So the fact that Shockley
47:04was such a bit stupid
47:06means that Silicon Valley
47:08exists today.
47:10Shockley's peculiar character
47:12could have caused
47:14the split of some companies,
47:16the creation of other new ones, etc.
47:28New companies competed
47:30with each other
47:32to surprise
47:34well-known companies.
47:36They developed transistors
47:38so small that they could be
47:40massively installed
47:42in an electric circuit
47:44printed in a fine cut
47:46of semiconductor glass.
47:50These chips,
47:52small and reliable,
47:54could be installed
47:56in all kinds of electronic devices,
47:58although their most popular use
48:00was in computers.
48:02Today, microchips
48:04are everywhere.
48:06They have transformed
48:08every aspect of modern life,
48:10from communication
48:12to transport
48:14or leisure.
48:16Perhaps as important
48:18as the current power
48:20of computer science
48:22is its ability
48:24to help us understand
48:26the universe
48:28in all its complexity.
48:30A single microchip
48:32like this one today
48:34can contain
48:36around 4 billion transistors.
48:38It's incredible
48:40how far technology
48:42has come in 60 years.
48:48It's easy to think
48:50that with the amount
48:52of advances that humanity
48:54has made in the study
48:56and the exploitation
48:58of electricity,
49:00there is little left to discover.
49:02But we would be wrong.
49:06For instance,
49:08continuous attempts
49:10to reduce the size
49:12of circuits
49:14have made a feature
49:16of electricity
49:18that was already known
49:20centuries ago
49:22become a problem.
49:24Resistance.
49:26The computer must be
49:28continuously refrigerated.
49:30Let's see what happens
49:32if we remove the fan.
49:34Wow, that's shooting up.
49:3640 degrees centigrade.
49:3860.
49:44100 degrees centigrade.
49:46And it cuts out.
49:48That just took a few seconds
49:50and the chip is well and truly cut.
49:52You see, as the electrons
49:54they're not just traveling around
49:56unfeeded, they're bumping
49:58into the atoms in the silicon
50:00and the energy being lost
50:02by the electrons is producing heat.
50:06Now, sometimes it's useful
50:08if ventures make electric heaters
50:10and ovens.
50:12Whenever we've got something to blow
50:14one pot, well, that's a light bulb.
50:16But resistance between electronic
50:18components and power lines
50:20is a major waste of energy
50:22and a major problem.
50:28It's estimated that resistance
50:30can take up to 20%
50:32of all the electricity
50:34we generate.
50:36It's one of the most serious
50:38problems of the contemporary era.
50:40Many research lines
50:42point precisely to that path.
50:48What we perceive as heat
50:50is really a measure
50:52of how much the atoms
50:54circulating are vibrating.
50:58And the gases that are vibrating
51:00against the electrons flowing
51:02through are more likely
51:04to generate hotter the material
51:06that generates a little resistance.
51:10And what happens
51:12if we cool a material
51:14perhaps to something
51:16from there,
51:18minus 270 degrees Celsius?
51:22Well, the absence of zero
51:24does not move the atoms at all.
51:26And so the atoms are not moving at all.
51:28What happens then
51:30to the flow of electricity
51:32and the flow of electrons?
51:34If we use a device
51:36called a cryostat,
51:38we can keep the materials
51:40at a temperature close
51:42to zero and check
51:44what happens.
51:46This cryostat coil
51:48is part of an electric circuit.
51:50Inside it,
51:52we have mercury,
51:54the famous liquid metal.
51:56This device will measure
51:58the resistance of the mercury.
52:00Look at what happens
52:02as I lower the mercury
52:04is the colder part of the cryostat.
52:10There it is.
52:12The resistance has brought
52:14to absolutely nothing.
52:16Mercury, like many substances
52:18as we now know,
52:20is all becoming superconducting,
52:22which means there has been
52:24no resistance at all
52:26to the flow of electricity.
52:30Cryostats only work
52:32when their temperature
52:34is very, very low.
52:36If our electrical installation
52:38or our appliances
52:40were made of some
52:42superconducting material,
52:44we would avoid the loss
52:46of much of our precious
52:48electrical energy.
52:50The problem, of course,
52:52is that superconductors
52:54had to be kept
52:56extremely low temperatures.
52:58In a small laboratory
53:00near Zurich, Switzerland,
53:02IBM physicists recently
53:04discovered their superconductivity
53:06in a new class of materials
53:08that has been called
53:10one of the most important
53:12scientific breakthroughs
53:14in many decades.
53:16This is a block of the same material
53:18made by the researchers
53:20in Switzerland.
53:22It doesn't look very remarkable,
53:24but if you cool it down
53:26something special happens.
53:30It becomes a superconductor,
53:32and due to the close bond
53:34between the two properties,
53:36it also develops surprising
53:38magnetic properties.
53:40This magnet
53:42is suspended, levitating
53:44above the superconductor.
53:50The most novel thing
53:52about the material
53:54is that the temperature
53:56is far from zero.
54:06These magnetic fields
54:08are so strong
54:10that not only can they
54:12support the weight
54:14of this magnet,
54:16but they should also
54:18support my weight.
54:20I'm about to be levitated.
54:22It's strange.
54:26When this material
54:28was first discovered in 1986,
54:30it created a revolution.
54:32Not only had no one
54:34considered that it might
54:36be superconductive,
54:38but it also had a temperature
54:40much more than anyone
54:42had thought possible.
54:44We are tantalizingly close
54:46to discovering
54:48superconductors at room temperature.
54:50We can use this material
54:52to build a cheaper,
54:54more sustainable world.
55:00Today, materials have been produced
55:02that exhibit this phenomenon
55:04at the sort of temperature
55:06you get in a freezer.
55:08But these new superconductors
55:10can't fully explain
55:12by intuitions.
55:14So without a complete
55:16scientific experimentalist,
55:18they are by our first
55:20scientific understanding.
55:22Recently, in a laboratory
55:24in Japan held a party
55:26where they ended up
55:28mixing their superconductors
55:30with a range of alcoholic beverages.
55:32Unexpectedly, they found
55:34that red wine improved
55:36the performance of superconductors.
55:40Electrical research
55:42now had the potential
55:44once again to revolutionize
55:46our society today
55:48through the discovery of
55:50superconductors at room temperature.
56:02Our dependence
56:04on electricity
56:06increases day by day.
56:08When we discover how to exploit
56:10superconductors,
56:12we will have a new world before us.
56:16It will be one of the most important
56:18periods of humanity,
56:20of constant discoveries.
56:22Numerous tools,
56:24techniques and technologies
56:26will be invented to once again
56:28transform our society.
56:36Electricity has changed our world.
56:38Just a couple of centuries ago,
56:40it was admired
56:42as a mysterious and magical wonder.
56:46We managed to get it out
56:48of the laboratory.
56:50After a series of brave experiments,
56:52we domesticated it and gave it use.
56:58Communication revolutionized,
57:00first with cables
57:02and then through probes,
57:04allowing us to reach very far places.
57:06It illuminates our daily life,
57:08making it impossible
57:10to imagine it without electricity.
57:12It defines our era.
57:14We are lost without it.
57:20In addition,
57:22day by day,
57:24it gives us the opportunity
57:26to be reborn,
57:28to revolutionize the world.
57:36But above all else,
57:38nothing more than
57:40those who know the science
57:42of electricity know.
57:44Its story is not over yet.
58:10To be continued...
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