La historia de la electricidad es fascinante y esencial para comprender el mundo moderno en el que vivimos. Desde sus orígenes en los experimentos de los antiguos griegos hasta la invención de la bombilla por Thomas Edison, la electricidad ha transformado nuestra vida cotidiana. Este documental, "La Historia de la Electricidad: Luz y Energía", te llevará a un viaje educativo a través del tiempo, explorando cómo se descubrieron y desarrollaron las teorías eléctricas, así como las innovaciones que permitieron la transmisión de energía eléctrica a gran escala.
Descubriremos cómo la electricidad ha impulsado la revolución industrial, facilitando el crecimiento de las ciudades y la creación de nuevas tecnologías. Además, analizaremos el impacto que tiene la electricidad en nuestras vidas actuales, desde el uso de electrodomésticos hasta la comunicación instantánea. Con imágenes impresionantes y explicaciones claras, este documental es ideal para quienes deseen profundizar en el tema y entender la importancia de la luz y la energía en nuestro día a día.
Al finalizar, los espectadores estarán mejor informados sobre los hitos en la historia de la electricidad y su relevancia en el desarrollo de la sociedad contemporánea. ¡No te pierdas este emocionante recorrido por el mundo de la electricidad!
**Hashtags:** #HistoriaDeLaElectricidad, #LuzYEnergia, #DocumentalEducativo
**Keywords:** historia de la electricidad, electricidad y energía, documental de electricidad, Thomas Edison, inventos eléctricos, revolución industrial, impacto de la electricidad, teoría eléctrica, tecnologías eléctricas, evolución de la energía.
Descubriremos cómo la electricidad ha impulsado la revolución industrial, facilitando el crecimiento de las ciudades y la creación de nuevas tecnologías. Además, analizaremos el impacto que tiene la electricidad en nuestras vidas actuales, desde el uso de electrodomésticos hasta la comunicación instantánea. Con imágenes impresionantes y explicaciones claras, este documental es ideal para quienes deseen profundizar en el tema y entender la importancia de la luz y la energía en nuestro día a día.
Al finalizar, los espectadores estarán mejor informados sobre los hitos en la historia de la electricidad y su relevancia en el desarrollo de la sociedad contemporánea. ¡No te pierdas este emocionante recorrido por el mundo de la electricidad!
**Hashtags:** #HistoriaDeLaElectricidad, #LuzYEnergia, #DocumentalEducativo
**Keywords:** historia de la electricidad, electricidad y energía, documental de electricidad, Thomas Edison, inventos eléctricos, revolución industrial, impacto de la electricidad, teoría eléctrica, tecnologías eléctricas, evolución de la energía.
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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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