1 00:00:08,160 --> 00:00:11,880 On the 14th August 1894, 2 00:00:11,880 --> 00:00:15,920 an excited crowd gathered outside Oxford's Natural History Museum. 3 00:00:18,680 --> 00:00:22,160 This huge Gothic building was hosting the annual meeting 4 00:00:22,160 --> 00:00:26,240 of the British Association for the Advancement of Science. 5 00:00:27,360 --> 00:00:30,880 Over 2,000 tickets had been sold in advance 6 00:00:30,880 --> 00:00:33,280 and the museum was already packed, 7 00:00:33,280 --> 00:00:37,920 waiting for the next talk to be given by Professor Oliver Lodge. 8 00:00:40,400 --> 00:00:43,720 His name might not be familiar to us now, 9 00:00:43,720 --> 00:00:46,800 but his discoveries should have made him as famous 10 00:00:46,800 --> 00:00:50,560 as some of the other great electrical pioneers of history. 11 00:00:50,560 --> 00:00:53,600 People like Benjamin Franklin, 12 00:00:53,600 --> 00:00:56,040 Alessandro Volta, 13 00:00:56,040 --> 00:00:59,880 or even the great Michael Faraday. 14 00:00:59,880 --> 00:01:05,080 Quite unwittingly, he would set in motion a series of events 15 00:01:05,080 --> 00:01:08,160 that would revolutionise the Victorian world 16 00:01:08,160 --> 00:01:10,720 of brass and telegraph wire. 17 00:01:10,720 --> 00:01:15,080 This lecture would mark the birth of the modern electrical world, 18 00:01:15,080 --> 00:01:19,880 a world dominated by silicone and mass wireless communication. 19 00:01:24,480 --> 00:01:29,520 In this programme, we discover how electricity connected the world together 20 00:01:29,520 --> 00:01:33,360 through broadcasting and computer networks, 21 00:01:33,360 --> 00:01:37,760 and how we finally learnt to unravel and exploit electricity 22 00:01:37,760 --> 00:01:41,360 at an atomic level. 23 00:01:41,360 --> 00:01:46,880 After centuries of man's experiments with electricity, 24 00:01:46,880 --> 00:01:50,960 a new age of real understanding was now dawning. 25 00:02:15,560 --> 00:02:19,880 These tubes are not plugged in to any power source, 26 00:02:19,880 --> 00:02:22,480 but they still light up. 27 00:02:22,480 --> 00:02:25,600 It's electricity's invisible effect, 28 00:02:25,600 --> 00:02:28,560 an effect not just confined to the wires it flows through. 29 00:02:31,040 --> 00:02:33,480 In the middle of the 19th century, 30 00:02:33,480 --> 00:02:37,760 a great theory was proposed to explain how this could be. 31 00:02:39,560 --> 00:02:43,560 The theory says that surrounding any electric charge - 32 00:02:43,560 --> 00:02:46,600 and there's a lot of electricity flowing above my head - 33 00:02:46,600 --> 00:02:48,400 is a force field. 34 00:02:48,400 --> 00:02:53,960 These florescent tubes are lit purely because they are under 35 00:02:53,960 --> 00:02:58,600 the influence of the force field from the power cables above. 36 00:03:00,720 --> 00:03:04,480 The theory that a flow of electricity could, in some way, 37 00:03:04,480 --> 00:03:07,880 create an invisible force field, was originally proposed 38 00:03:07,880 --> 00:03:13,040 by Michael Faraday, but it would take a brilliant young Scotsman 39 00:03:13,040 --> 00:03:18,440 called James Clark-Maxwell, who would prove Faraday correct - 40 00:03:18,440 --> 00:03:22,120 and not through experimentation, but through mathematics. 41 00:03:23,640 --> 00:03:28,480 This was all a far cry from the typical 19th century way 42 00:03:28,480 --> 00:03:30,920 of understanding how the world works, 43 00:03:30,920 --> 00:03:35,360 which was essentially to see it as a physical machine. 44 00:03:42,920 --> 00:03:47,240 Before Maxwell, scientists had often built strange machines 45 00:03:47,240 --> 00:03:51,840 or devised wondrous experiments to create and measure electricity. 46 00:03:53,280 --> 00:03:55,560 But Maxwell was different. 47 00:03:55,560 --> 00:04:00,200 He was interested in the numbers, and his new theory not only revealed 48 00:04:00,200 --> 00:04:05,360 electricity's invisible force field, but how it could be manipulated. 49 00:04:05,360 --> 00:04:08,480 It would prove to be one of the most important 50 00:04:08,480 --> 00:04:11,520 scientific discoveries of all time. 51 00:04:11,520 --> 00:04:14,440 Maxwell was a mathematician and a great one 52 00:04:14,440 --> 00:04:17,640 and he saw electricity and magnetism in an entirely new way. 53 00:04:17,640 --> 00:04:21,200 He expressed it all in terms of very compact mathematical equations. 54 00:04:21,200 --> 00:04:25,680 And the most important thing is that in Maxwell's equations 55 00:04:25,680 --> 00:04:31,560 is an understanding of electricity and magnetism as something linked 56 00:04:31,560 --> 00:04:34,200 and as something that can occur in waves. 57 00:04:42,960 --> 00:04:47,920 Maxwell's calculations showed how these fields could be disturbed 58 00:04:47,920 --> 00:04:52,160 rather like touching the surface of water with your finger. 59 00:04:52,160 --> 00:04:55,040 Changing the direction of the electric current 60 00:04:55,040 --> 00:04:57,880 would create a ripple or wave 61 00:04:57,880 --> 00:05:00,960 through these electric and magnetic fields. 62 00:05:00,960 --> 00:05:03,400 And constantly changing the direction 63 00:05:03,400 --> 00:05:06,080 of the flow of the current, forwards and backwards, 64 00:05:06,080 --> 00:05:12,520 like an alternating current, would produce a whole series of waves, 65 00:05:12,520 --> 00:05:15,600 waves that would carry energy. 66 00:05:17,360 --> 00:05:22,080 Maxwell's maths was telling him that changing electric currents 67 00:05:22,080 --> 00:05:25,400 would be constantly sending out great waves of energy 68 00:05:25,400 --> 00:05:27,080 into their surroundings. 69 00:05:27,080 --> 00:05:30,680 Waves that would carry on forever unless something absorbed them. 70 00:05:43,240 --> 00:05:47,520 Maxwell's maths was so advanced and complicated 71 00:05:47,520 --> 00:05:51,120 that only a handful of people understood it at the time, 72 00:05:51,120 --> 00:05:54,520 and although his work was still only a theory, 73 00:05:54,520 --> 00:06:00,320 it inspired a young German physicist called Heinrich Hertz. 74 00:06:00,320 --> 00:06:05,240 Hertz decided to dedicate himself to designing an experiment 75 00:06:05,240 --> 00:06:09,560 to prove that Maxwell's waves really existed. 76 00:06:11,120 --> 00:06:12,480 And here it is. 77 00:06:12,480 --> 00:06:16,320 This is Hertz's original apparatus 78 00:06:16,320 --> 00:06:20,280 and its beauty is in its sheer simplicity. 79 00:06:20,280 --> 00:06:24,080 Heat generates and alternating current that runs 80 00:06:24,080 --> 00:06:27,920 along these metal rods, with a spark that jumps across the gap 81 00:06:27,920 --> 00:06:29,880 between these two spheres. 82 00:06:29,880 --> 00:06:32,640 Now, if Maxwell was right, 83 00:06:32,640 --> 00:06:36,360 then this alternating current should generate an invisible 84 00:06:36,360 --> 00:06:40,920 electromagnetic wave that spreads out into the surroundings. 85 00:06:40,920 --> 00:06:44,640 If you place a wire in the path of that wave, 86 00:06:44,640 --> 00:06:50,240 then at the wire, there should be a changing electromagnetic field, 87 00:06:50,240 --> 00:06:54,400 which should induce an electric current in the wire. 88 00:06:54,400 --> 00:06:59,240 So what Hertz did was build this ring of wire, his receiver, 89 00:06:59,240 --> 00:07:02,680 that he could carry around in different positions in the room 90 00:07:02,680 --> 00:07:06,200 to see if he could detect the presence of the wave. 91 00:07:06,200 --> 00:07:10,720 And the way he did that was leave a very tiny gap in the wire, 92 00:07:10,720 --> 00:07:17,160 across which a spark would jump if a current runs through the ring. 93 00:07:17,160 --> 00:07:22,920 Now, because the current is so weak, that spark is very, very faint 94 00:07:22,920 --> 00:07:26,920 and Hertz spent pretty much most of 1887 95 00:07:26,920 --> 00:07:31,320 in a darkened room staring intensely through a lens 96 00:07:31,320 --> 00:07:35,200 to see if he could detect the presence of this faint spark. 97 00:07:43,000 --> 00:07:47,160 But Hertz wasn't alone in trying to create Maxwell's waves. 98 00:07:48,760 --> 00:07:53,000 Back in England, a young physics Professor called Oliver Lodge 99 00:07:53,000 --> 00:07:55,760 had been fascinated by the topic for years 100 00:07:55,760 --> 00:07:59,800 but hadn't had the time to design any experiments 101 00:07:59,800 --> 00:08:01,840 to try to discover them. 102 00:08:03,320 --> 00:08:08,000 Then one day, in early 1888, while setting up an experiment 103 00:08:08,000 --> 00:08:12,080 on lightning protection, he noticed something unusual. 104 00:08:15,400 --> 00:08:18,520 Lodge noticed that when he set up his equipment 105 00:08:18,520 --> 00:08:22,760 and sent an alternating current around the wires, 106 00:08:22,760 --> 00:08:26,720 he could see glowing patches between the wires, 107 00:08:26,720 --> 00:08:28,760 and with a bit of tweaking, 108 00:08:28,760 --> 00:08:32,600 he saw these glowing patches formed a pattern. 109 00:08:32,600 --> 00:08:36,960 The blue glow and electrical sparks occurred in distinct patches 110 00:08:36,960 --> 00:08:39,880 evenly spaced along the wires. 111 00:08:39,880 --> 00:08:43,360 He realised they were the peaks and troughs of a wave, 112 00:08:43,360 --> 00:08:45,840 an invisible electromagnetic wave. 113 00:08:47,560 --> 00:08:50,320 Lodge had proved that Maxwell was right. 114 00:08:51,920 --> 00:08:54,800 Finally, by accident, Lodge had created 115 00:08:54,800 --> 00:08:59,600 Maxwell's electromagnetic waves around the wires. 116 00:08:59,600 --> 00:09:02,440 The big question had been answered. 117 00:09:04,760 --> 00:09:08,680 Filled with excitement at his discovery, Lodge prepared 118 00:09:08,680 --> 00:09:13,080 to announce it to the world, at that summer's annual scientific meeting 119 00:09:13,080 --> 00:09:15,280 run by the British Association. 120 00:09:17,240 --> 00:09:20,600 Before it, though, he decided to go on holiday. 121 00:09:20,600 --> 00:09:25,480 His timing couldn't have been worse, because back in Germany, 122 00:09:25,480 --> 00:09:27,600 and at exactly the same time, 123 00:09:27,600 --> 00:09:31,520 Heinrich Hertz was also testing Maxwell's theories. 124 00:09:35,480 --> 00:09:39,720 Eventually, Hertz found what he was looking for... 125 00:09:39,720 --> 00:09:42,640 a minute spark. 126 00:09:42,640 --> 00:09:46,520 And as he carried his receiver to different positions in the room, 127 00:09:46,520 --> 00:09:50,000 he was able to map out the shape of the waves 128 00:09:50,000 --> 00:09:52,720 being produced by his apparatus. 129 00:09:52,720 --> 00:09:56,240 And he checked each of Maxwell's calculations carefully 130 00:09:56,240 --> 00:09:58,840 and tested them experimentally. 131 00:09:58,840 --> 00:10:02,080 It was a "tour de force" of experimental science. 132 00:10:07,280 --> 00:10:08,640 Back in Britain, 133 00:10:08,640 --> 00:10:11,800 as the crowds gathered for the British Association meeting, 134 00:10:11,800 --> 00:10:17,200 Oliver Lodge returned from holiday relaxed and full of anticipation. 135 00:10:21,720 --> 00:10:25,240 This, Lodge thought, would be his moment of triumph, 136 00:10:25,240 --> 00:10:29,840 when he could announce his discovery of Maxwell's waves. 137 00:10:29,840 --> 00:10:35,720 His great friend, the mathematician Fitzgerald, was due to give the opening address in the meeting. 138 00:10:35,720 --> 00:10:42,000 But in it, he proclaimed that Heinrik Hertz had just published astounding results. 139 00:10:42,000 --> 00:10:46,960 He had detected Maxwell's waves travelling through space. 140 00:10:46,960 --> 00:10:50,400 "We have snatched the thunderbolt from Jove himself 141 00:10:50,400 --> 00:10:54,880 "and enslaved the all prevailing ether", he announced. 142 00:10:54,880 --> 00:10:58,080 Well, I can only imagine how Lodge must have felt 143 00:10:58,080 --> 00:11:00,000 having his thunder stolen. 144 00:11:02,560 --> 00:11:06,840 Professor Oliver Lodge had lost his moment of triumph, 145 00:11:06,840 --> 00:11:11,080 pipped at the post by Heinrich Hertz. 146 00:11:11,080 --> 00:11:15,800 Hertz's spectacular demonstration of electromagnetic waves, what we now call radio waves, 147 00:11:15,800 --> 00:11:21,360 though he didn't know it at the time, will lead to a whole revolution in communications over the next century. 148 00:11:26,520 --> 00:11:30,080 Maxwell's theory had shown how electric charges could create 149 00:11:30,080 --> 00:11:33,520 a force field around them. 150 00:11:33,520 --> 00:11:37,720 And that waves could spread through these fields like ripples on a pond. 151 00:11:40,200 --> 00:11:43,880 And Hertz had built a device that could actually create 152 00:11:43,880 --> 00:11:47,360 and detect the waves as they passed through the air. 153 00:11:48,600 --> 00:11:50,640 But, almost immediately, 154 00:11:50,640 --> 00:11:55,880 there would be another revelation in our understanding of electricity. 155 00:11:55,880 --> 00:11:59,960 A revelation that would once again involve Professor Oliver Lodge. 156 00:11:59,960 --> 00:12:03,080 And, once again, his thunder would be stolen. 157 00:12:16,680 --> 00:12:21,960 The story starts in Oxford, in the summer of 1894. 158 00:12:21,960 --> 00:12:24,640 Hertz had died suddenly earlier that year, 159 00:12:24,640 --> 00:12:28,200 and so Lodge prepared a memorial lecture with a demonstration 160 00:12:28,200 --> 00:12:34,320 that would bring the idea of waves to a wider audience. 161 00:12:34,320 --> 00:12:36,520 Lodge had worked on his lecture. 162 00:12:36,520 --> 00:12:40,280 He'd researched better ways of detecting the waves, 163 00:12:40,280 --> 00:12:43,800 and he'd borrowed new apparatus from friends. 164 00:12:43,800 --> 00:12:48,080 He'd made some significant advances in the technology 165 00:12:48,080 --> 00:12:51,160 designed to detect the waves. 166 00:12:51,160 --> 00:12:56,080 This bit of apparatus generates an alternating current 167 00:12:56,080 --> 00:12:57,840 and a spark across this gap. 168 00:12:59,920 --> 00:13:04,240 The alternating current sends out an electromagnetic wave, 169 00:13:04,240 --> 00:13:08,680 just as Maxwell predicted, that is picked up by the receiver. 170 00:13:08,680 --> 00:13:14,000 It sets off a very weak electric current through these two antennae. 171 00:13:14,000 --> 00:13:16,600 Now, this is what Hertz had done. 172 00:13:16,600 --> 00:13:22,360 Lodge's improvement on this was to set up this tube full of iron fillings. 173 00:13:22,360 --> 00:13:25,320 The weak electric current passes through the filings, 174 00:13:25,320 --> 00:13:28,040 forcing them to clump together. 175 00:13:28,040 --> 00:13:31,800 And, when they do, they close a second electric circuit 176 00:13:31,800 --> 00:13:33,800 and set off the bell. 177 00:13:33,800 --> 00:13:36,160 So if I push the button on this end... 178 00:13:36,160 --> 00:13:39,480 BELL TINKLES ..it sets off the bell at the receiver. 179 00:13:39,480 --> 00:13:43,280 And it's doing that with no connections between the two. 180 00:13:43,280 --> 00:13:44,520 It's like magic. 181 00:13:44,520 --> 00:13:51,200 BELL RINGING/ELECTRICAL BUZZING 182 00:13:51,200 --> 00:13:53,400 If you could imagine a packed house, 183 00:13:53,400 --> 00:13:58,360 lots of people in the audience, and what they suddenly see is, 184 00:13:58,360 --> 00:14:01,280 as if by magic, a bell ringing. 185 00:14:01,280 --> 00:14:03,200 It's quite incredible. 186 00:14:03,200 --> 00:14:05,440 BELL RINGS 187 00:14:05,440 --> 00:14:10,360 It might not have been the most dramatic demonstration the audience had ever seen, 188 00:14:10,360 --> 00:14:14,800 but it certainly still created a sensation among the crowd. 189 00:14:14,800 --> 00:14:17,560 Lodge's apparatus, laid out like this, 190 00:14:17,560 --> 00:14:20,920 no longer looked like a scientific experiment. 191 00:14:20,920 --> 00:14:24,680 In fact, it looked remarkably like those telegraph machines 192 00:14:24,680 --> 00:14:30,080 that had revolutionised communication, but without those long cables 193 00:14:30,080 --> 00:14:34,040 stretching between the sending and receiving stations. 194 00:14:34,040 --> 00:14:37,440 To the more worldly and savvy members of the audience, 195 00:14:37,440 --> 00:14:42,880 this was clearly more than showing the maestro Maxwell was right. 196 00:14:42,880 --> 00:14:47,440 This was a revolutionary new form of communication. 197 00:14:52,320 --> 00:14:56,120 Lodge published his lecture notes on how electromagnetic waves 198 00:14:56,120 --> 00:15:00,720 could be sent and received using his new improvements. 199 00:15:00,720 --> 00:15:04,280 All around the world, inventors, amateur enthusiasts 200 00:15:04,280 --> 00:15:07,760 and scientists read Lodge's reports with excitement 201 00:15:07,760 --> 00:15:11,800 and began experimenting with Hertzian waves. 202 00:15:14,880 --> 00:15:19,600 Two utterly different characters were to be inspired by it. 203 00:15:19,600 --> 00:15:23,200 Both would bring improvements to the wireless telegraph, 204 00:15:23,200 --> 00:15:30,040 and both would be remembered for their contribution to science far more than Oliver Lodge. 205 00:15:30,040 --> 00:15:34,200 The first was Guglielmo Marconi. 206 00:15:34,200 --> 00:15:36,560 Marconi was a very intelligent, astute 207 00:15:36,560 --> 00:15:38,680 and a very charming individual. 208 00:15:38,680 --> 00:15:41,520 He definitely had the Italian, Irish charm. 209 00:15:41,520 --> 00:15:49,280 He could apply this to almost anyone from sort of young ladies to world-renowned scientists. 210 00:15:49,280 --> 00:15:51,280 Marconi was no scientist, 211 00:15:51,280 --> 00:15:55,120 but he read all he could of other people's work 212 00:15:55,120 --> 00:15:59,560 in order to put together his own wireless telegraph system. 213 00:15:59,560 --> 00:16:04,920 It's possible that because he was brought up in Bologna and it was fairly close to the Italian coast, 214 00:16:04,920 --> 00:16:11,080 that he saw the potential of wireless communications in relation to maritime usage fairly early on. 215 00:16:11,080 --> 00:16:15,560 Then, aged only 22, he came to London 216 00:16:15,560 --> 00:16:17,560 with his Irish mother to market it. 217 00:16:20,520 --> 00:16:25,080 The other person inspired by Lodge's lecture was a teacher 218 00:16:25,080 --> 00:16:28,440 at the Presidency College in Calcutta, 219 00:16:28,440 --> 00:16:31,200 called Jagadish Chandra Bose. 220 00:16:31,200 --> 00:16:35,240 Despite degrees from London and Cambridge, 221 00:16:35,240 --> 00:16:42,120 the appointment of an Indian as a scientist in Calcutta had been a battle against racial prejudice. 222 00:16:44,000 --> 00:16:50,400 Indians, it was said, didn't have the requisite temperament for exact science. 223 00:16:50,400 --> 00:16:53,840 Well, Bose was determined to prove this wrong, 224 00:16:53,840 --> 00:16:57,280 and here in the archives, we can see just how fast he set to work. 225 00:16:58,720 --> 00:17:04,000 This is a report of the 66th meeting of the British Association 226 00:17:04,000 --> 00:17:06,720 in Liverpool, September 1896. 227 00:17:06,720 --> 00:17:09,600 And here is Bose, 228 00:17:09,600 --> 00:17:13,240 the first Indian ever to present at the association meeting, 229 00:17:13,240 --> 00:17:17,840 talking about his work and demonstrating his apparatus. 230 00:17:17,840 --> 00:17:22,280 He'd built and improved on the detector that Lodge described, 231 00:17:22,280 --> 00:17:25,080 because in the hot, sticky Indian climate, 232 00:17:25,080 --> 00:17:30,520 he'd found that the metal filings inside the tube that Lodge used to detect the waves 233 00:17:30,520 --> 00:17:32,520 became rusty and stuck together. 234 00:17:32,520 --> 00:17:38,400 So Bose had to build a more practical detector using a coiled wire instead. 235 00:17:38,400 --> 00:17:41,600 His work was described as a sensation. 236 00:17:43,600 --> 00:17:47,640 The detector was extremely reliable and could work onboard ships, 237 00:17:47,640 --> 00:17:52,120 so had great potential for the vast British naval fleet. 238 00:17:52,120 --> 00:17:56,400 Britain was the centre of a vast telecommunications network 239 00:17:56,400 --> 00:17:58,600 which stretched almost around the world, 240 00:17:58,600 --> 00:18:04,240 which was used to support an equally vast maritime network of 241 00:18:04,240 --> 00:18:08,000 merchant and naval vessels, which were used to support the British Empire. 242 00:18:09,160 --> 00:18:16,520 But Bose, a pure scientist, wasn't interested in the commercial potential of wireless signals... 243 00:18:16,520 --> 00:18:18,960 unlike Marconi. 244 00:18:18,960 --> 00:18:23,560 This was sort of a new, cutting-edge field, but Marconi 245 00:18:23,560 --> 00:18:27,240 wasn't a trained scientist, so he came at things in a different way, 246 00:18:27,240 --> 00:18:32,040 which may have been why he progressed so quickly in the first place. 247 00:18:32,040 --> 00:18:35,520 And he was very good at forming connections with the people 248 00:18:35,520 --> 00:18:39,000 he needed to form connections with, to enable his work to be done. 249 00:18:41,520 --> 00:18:45,520 Marconi used his connections to go straight to the only place 250 00:18:45,520 --> 00:18:47,480 that had the resources to help him. 251 00:18:52,040 --> 00:18:55,720 The British Post Office was a hugely powerful institution. 252 00:18:55,720 --> 00:18:59,960 When Marconi first arrived in London in 1896, 253 00:18:59,960 --> 00:19:04,920 these buildings were newly completed and already heaving with business 254 00:19:04,920 --> 00:19:08,280 from the empire's postal and telegraphy services. 255 00:19:08,280 --> 00:19:12,880 Marconi had brought his telegraph system with him from Italy, 256 00:19:12,880 --> 00:19:17,160 claiming it could send wireless signals over unheard of distances. 257 00:19:17,160 --> 00:19:20,000 And the Post Office Engineer-in-Chief, 258 00:19:20,000 --> 00:19:24,400 William Preece, immediately saw the technology's potential. 259 00:19:26,200 --> 00:19:31,920 So, Preece offered Marconi the great financial and engineering resources 260 00:19:31,920 --> 00:19:36,640 of the Post Office, and they started work up on the roof. 261 00:19:38,400 --> 00:19:42,280 The old headquarters of the Post Office were right there. 262 00:19:42,280 --> 00:19:46,760 And between this roof and that one, Marconi and the Post Office engineers 263 00:19:46,760 --> 00:19:51,280 would practise sending and receiving electromagnetic waves. 264 00:19:51,280 --> 00:19:57,120 The engineers helped him improve his apparatus, and then Preece and Marconi together 265 00:19:57,120 --> 00:20:01,360 demonstrated it to influential people in Government and the Navy. 266 00:20:05,440 --> 00:20:07,600 What Preece didn't realise 267 00:20:07,600 --> 00:20:13,000 was that even as he was proudly announcing Marconi's successful partnership with the Post Office, 268 00:20:13,000 --> 00:20:16,920 Marconi was making plans behind the scenes. 269 00:20:18,640 --> 00:20:22,920 He'd applied for a British patent on the whole field of wireless telegraphy 270 00:20:22,920 --> 00:20:26,720 and was planning on setting up his own company. 271 00:20:26,720 --> 00:20:30,720 When the patent was granted, all hell broke loose 272 00:20:30,720 --> 00:20:33,360 in the scientific community. 273 00:20:37,160 --> 00:20:40,120 That patent was itself revolutionary. 274 00:20:43,480 --> 00:20:46,360 You see, patents could only be taken out on things 275 00:20:46,360 --> 00:20:48,640 that weren't public knowledge, 276 00:20:48,640 --> 00:20:53,720 but Marconi famously had hidden his equipment in a secret box. 277 00:20:58,120 --> 00:21:00,000 And here it is. 278 00:21:00,000 --> 00:21:02,680 When his patent was finally granted, 279 00:21:02,680 --> 00:21:06,440 Marconi ceremoniously opened the box. 280 00:21:06,440 --> 00:21:09,720 Everyone was keen to see what inventions lay within. 281 00:21:13,880 --> 00:21:15,720 Batteries forming a circuit, 282 00:21:15,720 --> 00:21:18,240 iron filings in the tube to complete the circuit 283 00:21:18,240 --> 00:21:20,480 to ring the bell on top. 284 00:21:20,480 --> 00:21:26,880 Nothing they hadn't seen before, and yet, Marconi had patented the lot. 285 00:21:28,480 --> 00:21:32,160 The reason Marconi is famous is not because of that invention. 286 00:21:32,160 --> 00:21:35,720 He doesn't invent radio, but he improves it 287 00:21:35,720 --> 00:21:37,680 and turns it into a system. 288 00:21:37,680 --> 00:21:41,680 Lodge doesn't do that. And that's why we remember Marconi, 289 00:21:41,680 --> 00:21:44,440 and that's why we don't remember Lodge. 290 00:21:48,640 --> 00:21:51,720 The scientific world was up in arms. 291 00:21:51,720 --> 00:21:56,600 Here was this young man who knew very little about the science behind his equipment 292 00:21:56,600 --> 00:22:00,520 about to make his fortune, from their work. 293 00:22:00,520 --> 00:22:04,640 Even his great supporter Preece, was disappointed and hurt 294 00:22:04,640 --> 00:22:09,440 when he found out Marconi was about to go it alone and set up his own company. 295 00:22:09,440 --> 00:22:14,160 Lodge and other scientists began a frenzy of patenting 296 00:22:14,160 --> 00:22:18,480 every tiny detail and improvement they made to their equipment. 297 00:22:21,760 --> 00:22:26,880 This new atmosphere shocked Bose when he returned to Britain. 298 00:22:28,080 --> 00:22:32,960 Bose wrote home to India in disgust at what he found in England. 299 00:22:32,960 --> 00:22:37,880 "Money, money, money all the time, what a devouring greed! 300 00:22:37,880 --> 00:22:43,200 "I wish you could see the craze for money of the people here." 301 00:22:43,200 --> 00:22:46,720 His disillusionment with the changes he saw 302 00:22:46,720 --> 00:22:53,080 in the country he revered for scientific integrity and excellence is palpable. 303 00:22:53,080 --> 00:22:55,720 Eventually, though, it was his friends 304 00:22:55,720 --> 00:22:59,880 who convinced Bose to take out his one and only patent, 305 00:22:59,880 --> 00:23:04,320 on his discovery of a new kind of detector for waves. 306 00:23:04,320 --> 00:23:10,240 It was this discovery that would lead to perhaps an even greater revolution for the world. 307 00:23:10,240 --> 00:23:14,480 He had discovered the power of crystals. 308 00:23:16,080 --> 00:23:19,440 This replaces older techniques using iron filings, which are 309 00:23:19,440 --> 00:23:21,920 messy and difficult and don't work well. 310 00:23:21,920 --> 00:23:25,040 And here's a whole new way of detecting radio waves, 311 00:23:25,040 --> 00:23:28,200 and it's one that's going to be at the centre of a radio industry. 312 00:23:29,520 --> 00:23:32,160 Bose's discovery was simple, 313 00:23:32,160 --> 00:23:36,800 but it would truly shape the modern world. 314 00:23:36,800 --> 00:23:42,320 When some crystals are touched with metal to test their electrical conductivity, 315 00:23:42,320 --> 00:23:46,680 they can show rather odd and varied behaviour. 316 00:23:46,680 --> 00:23:49,000 Take this crystal, for example. 317 00:23:49,000 --> 00:23:53,880 If I can touch it in exactly the right spot with the tip of this metal wire, 318 00:23:53,880 --> 00:23:57,120 and then hook it up to a battery, 319 00:23:57,120 --> 00:23:59,800 it gives quite a significant current. 320 00:24:01,920 --> 00:24:04,840 But if I switch round my connections to the battery 321 00:24:04,840 --> 00:24:08,960 and try and pass the current through in the opposite direction... 322 00:24:08,960 --> 00:24:10,520 it's a lot less. 323 00:24:12,880 --> 00:24:18,280 It's not a full conductor of electricity, it's a semi-conductor. 324 00:24:18,280 --> 00:24:23,760 And it found its first use in detecting electromagnetic waves. 325 00:24:23,760 --> 00:24:27,760 When Bose used a crystal like this in his circuits 326 00:24:27,760 --> 00:24:30,800 instead of the tube of filings, 327 00:24:30,800 --> 00:24:36,520 he found it was a much more efficient and effective detector of electromagnetic waves. 328 00:24:36,520 --> 00:24:41,240 It was this strange property of the junction between the wire, 329 00:24:41,240 --> 00:24:45,920 known as the "cat's whisker", and the crystal, which allowed current to pass 330 00:24:45,920 --> 00:24:49,120 much more easily on one direction than the other, 331 00:24:49,120 --> 00:24:54,720 that meant it could be used to extract a signal from electromagnetic waves. 332 00:24:56,640 --> 00:25:03,040 At the time, no-one had any idea why certain crystals acted in this way. 333 00:25:03,040 --> 00:25:07,480 But to scientists and engineers, this strange behaviour 334 00:25:07,480 --> 00:25:11,600 had a profound and almost miraculous practical effect. 335 00:25:12,840 --> 00:25:16,040 With crystals as detectors, 336 00:25:16,040 --> 00:25:25,000 now it was possible to broadcast and detect the actual sound of a human voice, or music. 337 00:25:36,240 --> 00:25:38,840 In his Oxford lecture in 1894, 338 00:25:38,840 --> 00:25:42,760 Oliver Lodge had opened a Pandora's box. 339 00:25:42,760 --> 00:25:49,600 As an academic, he'd failed to foresee that the scientific discoveries he'd been such a part of 340 00:25:49,600 --> 00:25:52,440 had such commercial potential. 341 00:25:52,440 --> 00:25:54,880 The one patent he had managed to secure, 342 00:25:54,880 --> 00:25:59,880 the crucial means of tuning a receiver to a particular radio signal, 343 00:25:59,880 --> 00:26:04,680 was bought off him by Marconi's powerful company. 344 00:26:09,240 --> 00:26:12,040 Perhaps the worst indignation for Lodge, though, 345 00:26:12,040 --> 00:26:14,480 would come in 1909, 346 00:26:14,480 --> 00:26:19,760 when Marconi was awarded the Nobel Prize in Physics for wireless communication. 347 00:26:21,320 --> 00:26:25,360 It's difficult to imagine a bigger snub to the physicist 348 00:26:25,360 --> 00:26:29,520 who'd so narrowly missed out to Hertz in the discovery of radio waves, 349 00:26:29,520 --> 00:26:31,720 and who'd then go on to show the world 350 00:26:31,720 --> 00:26:34,120 how they could be sent and received. 351 00:26:36,520 --> 00:26:40,080 'But despite this snub, Lodge remained magnanimous, 352 00:26:40,080 --> 00:26:44,640 'using the new broadcasting technology that resulted from his work 353 00:26:44,640 --> 00:26:46,400 'to give credit to others, 354 00:26:46,400 --> 00:26:49,600 'as this rare film of him shows.' 355 00:26:49,600 --> 00:26:51,600 Hertz made a great advance. 356 00:26:53,040 --> 00:26:57,960 He discovered how to produce and detect waves in space, 357 00:26:57,960 --> 00:27:00,720 thus bringing the ether into practical use. 358 00:27:01,920 --> 00:27:05,880 Harnessing it, harnessing it for the transmission of intelligence 359 00:27:05,880 --> 00:27:09,880 in a way which has subsequently been elaborated by a number of people. 360 00:27:21,720 --> 00:27:26,040 Today, we can hardly imagine a world without broadcasting, 361 00:27:26,040 --> 00:27:29,920 to imagine a time when radio waves hadn't even been dreamt of. 362 00:27:31,480 --> 00:27:35,440 Engineers continued to refine and perfect our ability 363 00:27:35,440 --> 00:27:38,880 to transmit and receive electromagnetic waves, 364 00:27:38,880 --> 00:27:44,360 but their discovery was ultimately a triumph of pure science, 365 00:27:44,360 --> 00:27:47,840 from Maxwell, through Hertz, to Lodge. 366 00:27:47,840 --> 00:27:53,240 But still, the very nature of electricity itself remained unexplained. 367 00:27:53,240 --> 00:27:58,400 What created those electrical charges and currents in the first place? 368 00:28:00,680 --> 00:28:04,200 Although scientists were learning to exploit electricity, 369 00:28:04,200 --> 00:28:09,000 they still didn't know what it actually was. 370 00:28:09,000 --> 00:28:12,160 But this question was being answered with experiments 371 00:28:12,160 --> 00:28:16,280 looking into how electricity flowed through different materials. 372 00:28:17,600 --> 00:28:22,280 Back in the 1850s, one of Germany's great experimentalists 373 00:28:22,280 --> 00:28:25,640 and a talented glass blower, Heinrich Geissler, 374 00:28:25,640 --> 00:28:28,440 created these beautiful showpieces. 375 00:28:28,440 --> 00:28:31,560 ELECTRICITY BUZZES 376 00:28:37,720 --> 00:28:42,040 Geissler pumped most of the air out of these intricate glass tubes 377 00:28:42,040 --> 00:28:45,520 and then had small amounts of other gases pumped in. 378 00:28:49,000 --> 00:28:52,720 He then passed an electrical current through them. 379 00:28:52,720 --> 00:28:55,080 They glowed with stunning colours, 380 00:28:55,080 --> 00:28:59,160 and the current flowing through the gas seemed tangible. 381 00:29:01,400 --> 00:29:04,600 Although they were designed purely for entertainment, 382 00:29:04,600 --> 00:29:09,800 over the next 50 years, scientists saw Giessler's tubes as a chance 383 00:29:09,800 --> 00:29:12,360 to study how electricity flowed. 384 00:29:14,240 --> 00:29:18,360 Efforts were made to pump more and more air out of the tubes. 385 00:29:18,360 --> 00:29:22,640 Could the electric current pass through nothingness? 386 00:29:22,640 --> 00:29:24,160 Through the vacuum? 387 00:29:28,760 --> 00:29:34,440 This is a very rare flick book film of the British scientist 388 00:29:34,440 --> 00:29:38,560 who created a vacuum good enough to answer that question. 389 00:29:38,560 --> 00:29:40,640 His name was William Crookes. 390 00:29:42,560 --> 00:29:45,320 Crookes create tubes like this. 391 00:29:45,320 --> 00:29:48,360 He pumped out as much of the air as he could 392 00:29:48,360 --> 00:29:52,120 so that it was as close to a vacuum as he could make it. 393 00:29:52,120 --> 00:29:55,840 Then, when he passed an electrical current through the tube... 394 00:29:55,840 --> 00:29:58,840 ELECTRICAL BUZZING 395 00:29:58,840 --> 00:30:02,320 ..he noticed a bright glow on the far end. 396 00:30:02,320 --> 00:30:05,600 A beam seemed to be shining through the tube 397 00:30:05,600 --> 00:30:08,120 and hitting the glass at the other end. 398 00:30:08,120 --> 00:30:11,720 It seemed, at last, we could see electricity. 399 00:30:11,720 --> 00:30:14,880 The beam became known as a cathode ray, 400 00:30:14,880 --> 00:30:18,920 and this tube was the forerunner of the cathode ray tube 401 00:30:18,920 --> 00:30:22,320 that was used in television sets for decades. 402 00:30:26,840 --> 00:30:31,680 Physicist JJ Thompson discovered that these beams 403 00:30:31,680 --> 00:30:35,320 were made up of tiny, negatively charged particles, 404 00:30:35,320 --> 00:30:41,040 and because they were carriers of electricity, they became known as electrons. 405 00:30:42,320 --> 00:30:45,440 Because the electrons only moved in one direction, 406 00:30:45,440 --> 00:30:50,080 from the heated metal plate through the positively charged plate at the other end, 407 00:30:50,080 --> 00:30:55,880 they behaved in exactly the same way as Bose's semi-conductor crystals. 408 00:30:55,880 --> 00:30:59,640 But, whereas Bose's crystals were naturally temperamental - 409 00:30:59,640 --> 00:31:02,680 you had to find the right spot for them to work - 410 00:31:02,680 --> 00:31:05,720 these tubes could be manufactured consistently. 411 00:31:06,760 --> 00:31:08,760 They became known as valves, 412 00:31:08,760 --> 00:31:13,080 and they soon replaced crystals in radio sets everywhere. 413 00:31:17,320 --> 00:31:21,680 These discoveries would lead to an explosion of new technology. 414 00:31:22,960 --> 00:31:27,600 Early 20th century electronics is all about what you can do with valves. 415 00:31:27,600 --> 00:31:30,080 So, the radio industries is built on valves, 416 00:31:30,080 --> 00:31:32,080 early television is built on valves, 417 00:31:32,080 --> 00:31:34,280 early computers are built with valves. 418 00:31:34,280 --> 00:31:37,120 These are what you build the electronic world with. 419 00:31:39,600 --> 00:31:44,680 Having discovered how to manipulate electrons flowing through a vacuum, 420 00:31:44,680 --> 00:31:47,680 scientists were now keen to understand 421 00:31:47,680 --> 00:31:50,520 how they could flow through other materials. 422 00:31:51,600 --> 00:31:56,040 But that meant understanding the things that made up materials - 423 00:31:56,040 --> 00:31:57,520 atoms. 424 00:32:07,920 --> 00:32:12,120 It was in the early years of the 20th century that we finally 425 00:32:12,120 --> 00:32:17,000 got a handle on exactly what atoms were made up of and how they behaved. 426 00:32:18,320 --> 00:32:22,880 And so, what electricity actually was on the atomic scale. 427 00:32:25,200 --> 00:32:29,000 At the University of Manchester, Ernest Rutherford's team 428 00:32:29,000 --> 00:32:31,800 were studying the inner structure of the atom 429 00:32:31,800 --> 00:32:36,080 and producing a picture to describe what an atom looked like. 430 00:32:36,080 --> 00:32:43,600 This revelation would finally help explain some of the more puzzling features of electricity. 431 00:32:43,600 --> 00:32:47,960 By 1913, the picture of the atom was one in which you had 432 00:32:47,960 --> 00:32:50,640 a positively charged nucleus in the middle 433 00:32:50,640 --> 00:32:55,120 surrounded by negatively charged orbiting electrons, 434 00:32:55,120 --> 00:32:57,360 in patterns called shells. 435 00:32:57,360 --> 00:33:02,920 Each of these shells corresponded to an electron with a particular energy. 436 00:33:02,920 --> 00:33:06,520 Now, given an energy boost, an electron could jump 437 00:33:06,520 --> 00:33:09,120 from an inner shell to an outer one. 438 00:33:09,120 --> 00:33:11,760 And the energy had to be just right - 439 00:33:11,760 --> 00:33:15,600 if it wasn't enough, the electron wouldn't make the transition. 440 00:33:15,600 --> 00:33:18,920 And this boost was often temporary because the electron 441 00:33:18,920 --> 00:33:22,160 would then drop back down again to its original shell. 442 00:33:22,160 --> 00:33:25,640 As it did this, it had to give off its excess energy 443 00:33:25,640 --> 00:33:27,760 by spitting out a photon... 444 00:33:28,800 --> 00:33:33,280 ..and the energy of each photon depended on its wavelength, 445 00:33:33,280 --> 00:33:36,000 or, as we would perceive it, its colour. 446 00:33:39,120 --> 00:33:43,200 Understanding the structure of atoms could now also explain 447 00:33:43,200 --> 00:33:45,840 nature's great electrical light shows. 448 00:33:45,840 --> 00:33:48,640 THUNDER 449 00:33:48,640 --> 00:33:50,440 Just like Geissler's tubes, 450 00:33:50,440 --> 00:33:54,960 the type of gas the electricity passes through defines its colour. 451 00:33:58,080 --> 00:34:03,040 Lightning has a blue tinge because of the nitrogen in our atmosphere. 452 00:34:04,280 --> 00:34:08,160 Higher in the atmosphere, the gases are different 453 00:34:08,160 --> 00:34:12,320 and so is the colour of the photons they produce, 454 00:34:12,320 --> 00:34:14,560 creating the spectacular auroras. 455 00:34:20,560 --> 00:34:24,600 Understanding atoms, how they fit together in materials 456 00:34:24,600 --> 00:34:29,800 and how their electrons behave, was the final key to understanding 457 00:34:29,800 --> 00:34:32,560 the fundamental nature of electricity. 458 00:34:38,280 --> 00:34:40,480 This is a Wimshurst Machine 459 00:34:40,480 --> 00:34:43,160 and it's used to generate electric charge. 460 00:34:45,840 --> 00:34:50,400 Electrons are rubbed off these discs and start a flow of electricity 461 00:34:50,400 --> 00:34:53,000 through the metal arms of the machine. 462 00:34:55,960 --> 00:34:57,880 Now, metals conduct electricity 463 00:34:57,880 --> 00:35:01,800 because the electrons are very weakly bound inside their atoms 464 00:35:01,800 --> 00:35:06,520 and so can slosh about and be used to flow as electricity. 465 00:35:06,520 --> 00:35:09,680 Insulators, on the other hand, don't conduct electricity 466 00:35:09,680 --> 00:35:13,320 because the electrons are very tightly bound inside the atoms 467 00:35:13,320 --> 00:35:15,040 and are not free to move about. 468 00:35:17,240 --> 00:35:20,040 The flow of electrons, and hence electricity, 469 00:35:20,040 --> 00:35:22,600 through materials was now understood. 470 00:35:22,600 --> 00:35:26,200 Conductors and insulators could be explained. 471 00:35:26,200 --> 00:35:28,280 What was more difficult to understand 472 00:35:28,280 --> 00:35:31,560 was the strange properties of semi-conductors. 473 00:35:34,960 --> 00:35:39,320 Our modern electronic world is built upon semi-conductors 474 00:35:39,320 --> 00:35:42,600 and would grind to a halt without them. 475 00:35:42,600 --> 00:35:48,880 Jagadish Chandra Bose may have stumbled upon their properties back in the 1890s, 476 00:35:48,880 --> 00:35:54,120 but no-one could have foreseen just how important they were to become. 477 00:35:55,600 --> 00:35:58,320 But, with the outbreak of the Second World War, 478 00:35:58,320 --> 00:36:00,040 things were about to change. 479 00:36:06,000 --> 00:36:09,960 Here in Oxford, this newly built physics laboratory 480 00:36:09,960 --> 00:36:13,320 was immediately handed over to the war research effort. 481 00:36:13,320 --> 00:36:17,600 The researchers here were tasked with improving the British radar system. 482 00:36:23,600 --> 00:36:27,480 Radar was a technology that used electromagnetic waves 483 00:36:27,480 --> 00:36:31,600 to detect enemy bombers, and as its accuracy improved, 484 00:36:31,600 --> 00:36:35,800 it became clear that valves just weren't up to the job. 485 00:36:39,320 --> 00:36:42,800 So, the team had to turn to old technology - 486 00:36:42,800 --> 00:36:47,560 instead of valves, they used semi-conductor crystals. 487 00:36:47,560 --> 00:36:50,120 Now, they didn't use the same sort of crystals 488 00:36:50,120 --> 00:36:53,120 that Bose had developed - instead they used silicon. 489 00:36:56,400 --> 00:37:00,640 This device is a silicon crystal receiver. 490 00:37:00,640 --> 00:37:03,520 There's a tiny tungsten wire coiled down 491 00:37:03,520 --> 00:37:07,400 and touching the surface of a little silicon crystal. 492 00:37:07,400 --> 00:37:10,960 It's incredible how important a device it was. 493 00:37:14,520 --> 00:37:20,120 It was the first time silicon had really been exploited as a semi-conductor, 494 00:37:20,120 --> 00:37:24,240 but for it to work, it needed to be very pure 495 00:37:24,240 --> 00:37:29,240 and both sides in the war put a lot of resources into purifying it. 496 00:37:31,120 --> 00:37:34,720 In fact, the British had better silicon devices 497 00:37:34,720 --> 00:37:39,160 so they must have had some coils of silicon already at that time 498 00:37:39,160 --> 00:37:43,560 which we were just starting with, you know, in Berlin. 499 00:37:45,080 --> 00:37:48,360 The British had better silicon semi-conductors 500 00:37:48,360 --> 00:37:52,080 because they had help from laboratories in the US, 501 00:37:52,080 --> 00:37:54,640 in particular, the famous Bell Labs. 502 00:37:54,640 --> 00:37:58,360 And it wasn't long before physicists realised 503 00:37:58,360 --> 00:38:01,960 that if semi-conductors could replace valves in radar, 504 00:38:01,960 --> 00:38:07,320 perhaps they could replace valves in other devices too, like amplifiers. 505 00:38:09,920 --> 00:38:14,240 The simple vacuum tube, with its one-way stream of electrons, 506 00:38:14,240 --> 00:38:17,560 had been modified to produce a new device. 507 00:38:17,560 --> 00:38:21,040 By placing a metal grill in the path of the electrons 508 00:38:21,040 --> 00:38:22,960 and applying a tiny voltage to it, 509 00:38:22,960 --> 00:38:26,760 a dramatic change in the strength of the beam could be produced. 510 00:38:26,760 --> 00:38:29,520 These valves worked as amplifiers, 511 00:38:29,520 --> 00:38:33,760 turning a very weak electrical signal into a much stronger one. 512 00:38:33,760 --> 00:38:37,120 An amplifier is something, in one sense, really simple. 513 00:38:37,120 --> 00:38:41,800 You just take a small current, you turn it into a larger current. 514 00:38:41,800 --> 00:38:44,800 But in other ways, it changes the world, 515 00:38:44,800 --> 00:38:49,120 because when you can amplify a signal, you can send it anywhere in the world. 516 00:38:52,760 --> 00:38:57,160 As soon as the war was over, German expert Herbert Matare 517 00:38:57,160 --> 00:39:00,800 and his colleague, Heinrich Welker, started to build 518 00:39:00,800 --> 00:39:05,320 a semi-conductor device that could be used as an electrical amplifier. 519 00:39:06,600 --> 00:39:13,280 And here is that first working model that Matare and Welker made. 520 00:39:13,280 --> 00:39:16,520 If you look inside, you can see the tiny crystal 521 00:39:16,520 --> 00:39:20,000 and the wires that make contact with it. 522 00:39:20,000 --> 00:39:23,440 If you pass a small current through one of the wires, 523 00:39:23,440 --> 00:39:27,440 this allows a much larger current to flow through the other one, 524 00:39:27,440 --> 00:39:31,080 so it was acting as a signal amplifier. 525 00:39:33,840 --> 00:39:38,880 These tiny devices could replace big, expensive valves 526 00:39:38,880 --> 00:39:44,040 in long distance telephone networks, radios and other equipment 527 00:39:44,040 --> 00:39:47,120 where a faint signal needed boosting. 528 00:39:47,120 --> 00:39:50,600 Matare immediately realised what he'd created, 529 00:39:50,600 --> 00:39:53,600 but his bosses were initially not interested. 530 00:39:53,600 --> 00:39:56,760 Not, that is, until a paper appeared in a journal 531 00:39:56,760 --> 00:39:59,120 announcing a Bell Labs discovery. 532 00:40:03,160 --> 00:40:07,000 A research team there had stumbled across the same effect 533 00:40:07,000 --> 00:40:11,080 and now they were announcing their invention to the world. 534 00:40:11,080 --> 00:40:13,280 They called it the transistor. 535 00:40:15,040 --> 00:40:20,920 They had it in December 1947, and we had it in beginning '48. 536 00:40:20,920 --> 00:40:24,760 But just, just life, you know. 537 00:40:24,760 --> 00:40:28,600 They had it a little bit earlier, the effect. 538 00:40:28,600 --> 00:40:33,080 But, funnily enough, their transistors were just no good. 539 00:40:35,120 --> 00:40:38,480 Although the European device was more reliable 540 00:40:38,480 --> 00:40:41,640 than Bell Labs' more experimental model, 541 00:40:41,640 --> 00:40:44,800 neither quite fulfilled their promise - 542 00:40:44,800 --> 00:40:47,880 they worked, but were just too delicate. 543 00:40:49,240 --> 00:40:53,920 So the search was on for a more robust way to amplify electrical signals 544 00:40:53,920 --> 00:40:57,280 and the breakthrough came by accident. 545 00:40:58,800 --> 00:41:02,480 In Bell Labs, silicon crystal expert Russell Ohl 546 00:41:02,480 --> 00:41:06,880 noticed that one of his silicon ingots had a really bizarre property. 547 00:41:06,880 --> 00:41:10,880 It seemed to be able to generate its own voltage 548 00:41:10,880 --> 00:41:14,720 and when he tried to measure this by hooking it up to an Oscilloscope, 549 00:41:14,720 --> 00:41:18,200 he noticed that the voltage changed all the time. 550 00:41:18,200 --> 00:41:21,800 The amount of voltage it generated seemed to depend on 551 00:41:21,800 --> 00:41:24,360 how much light there was in the room. 552 00:41:24,360 --> 00:41:28,000 So, by casting a shadow over the crystal, 553 00:41:28,000 --> 00:41:30,120 he saw the voltage dropped. 554 00:41:30,120 --> 00:41:33,520 More light meant the voltage went up. 555 00:41:33,520 --> 00:41:40,200 What's more, when he turned a fan on between the lamp and the crystal 556 00:41:40,200 --> 00:41:44,440 the voltage started to oscillate with the same frequency 557 00:41:44,440 --> 00:41:49,360 that the blades of the fan were casting shadows over the crystal. 558 00:41:52,320 --> 00:41:56,040 One of Ohl's colleagues immediately realised 559 00:41:56,040 --> 00:42:00,600 that the ingot had a crack in it that formed a natural junction, 560 00:42:00,600 --> 00:42:05,040 and this tiny natural junction in an otherwise solid block 561 00:42:05,040 --> 00:42:09,040 was acting just like the much more delicate junction 562 00:42:09,040 --> 00:42:14,280 between the end of a wire and a crystal that Bose had discovered. 563 00:42:14,280 --> 00:42:16,560 Except here, it was sensitive to light. 564 00:42:18,760 --> 00:42:23,320 The ingot had cracked because either side contained 565 00:42:23,320 --> 00:42:27,000 slightly different amounts of impurities. 566 00:42:27,000 --> 00:42:30,880 One side had slightly more of the element phosphorous, 567 00:42:30,880 --> 00:42:35,720 while the other had slightly more of a different impurity - boron. 568 00:42:35,720 --> 00:42:38,320 And electrons seemed to be able to move across 569 00:42:38,320 --> 00:42:43,240 from the phosphorous side to the boron side, but not vice versa. 570 00:42:43,240 --> 00:42:46,600 Photons of light shining down onto the crystal 571 00:42:46,600 --> 00:42:49,160 were knocking electrons out of the atoms, 572 00:42:49,160 --> 00:42:53,040 but it was the impurity atoms that were driving this flow. 573 00:42:55,040 --> 00:42:59,400 Phosphorous has an electron that is going spare... 574 00:42:59,400 --> 00:43:02,360 and boron is keen to accept another, 575 00:43:02,360 --> 00:43:06,840 so electrons tended to flow from the phosphorous side 576 00:43:06,840 --> 00:43:12,000 to the boron side and, crucially, only flowed one way across the junction. 577 00:43:19,160 --> 00:43:22,600 The head of the semi-conductor team, William Shockley, 578 00:43:22,600 --> 00:43:26,840 saw the potential of this one-way junction within a crystal, 579 00:43:26,840 --> 00:43:30,960 but how would it be possible to create a crystal 580 00:43:30,960 --> 00:43:34,840 with two junctions in it that could be used as an amplifier? 581 00:43:36,080 --> 00:43:39,560 Another researcher at Bell Labs called Gordon Teal 582 00:43:39,560 --> 00:43:43,360 had been working on a technique that would allow just that. 583 00:43:45,360 --> 00:43:49,200 He'd discovered a special way to grow single crystals 584 00:43:49,200 --> 00:43:52,200 of the semi-conductor germanium. 585 00:43:55,240 --> 00:43:58,840 In this research institute, they grow semi-conductor crystals 586 00:43:58,840 --> 00:44:02,920 in the same way that Teal did back in Bell Labs - 587 00:44:02,920 --> 00:44:05,840 only here, they grow them much, much bigger. 588 00:44:10,280 --> 00:44:15,040 At the bottom of this vat is a container with glowing hot, 589 00:44:15,040 --> 00:44:18,880 molten germanium, just as pure as you can get it. 590 00:44:18,880 --> 00:44:24,600 Inside it are a few atoms of whatever impurity is required 591 00:44:24,600 --> 00:44:27,040 to alter its conductive properties. 592 00:44:27,040 --> 00:44:32,560 Now, the rotating arm above has a seed crystal at the bottom 593 00:44:32,560 --> 00:44:37,800 that has been dipped into the liquid and will be slowly raised up again. 594 00:44:42,120 --> 00:44:47,360 As the germanium cools and hardens, it forms a long crystal 595 00:44:47,360 --> 00:44:49,520 like an icicle, below the seed. 596 00:44:49,520 --> 00:44:54,600 The whole length is one single, beautiful germanium crystal. 597 00:45:02,560 --> 00:45:05,560 Teal worked out that, as the crystal is growing, 598 00:45:05,560 --> 00:45:10,320 other impurities can be added to the vat and mixed in. 599 00:45:10,320 --> 00:45:16,000 This gives us a single crystal with thin layers of different impurities 600 00:45:16,000 --> 00:45:20,120 creating junctions within the crystal. 601 00:45:27,800 --> 00:45:31,880 This crystal with two junctions in it was Shockley's dream. 602 00:45:31,880 --> 00:45:36,320 Applying a small current through the very thin middle section 603 00:45:36,320 --> 00:45:41,360 allows a much larger current to flow through the whole triple sandwich. 604 00:45:44,960 --> 00:45:47,680 From a single crystal like this, 605 00:45:47,680 --> 00:45:51,200 hundreds of tiny solid blocks could be cut, 606 00:45:51,200 --> 00:45:56,840 each containing the two junctions that would allow the movement of electrons through them 607 00:45:56,840 --> 00:45:58,960 to be precisely controlled. 608 00:46:01,360 --> 00:46:04,960 These tiny and reliable devices 609 00:46:04,960 --> 00:46:08,800 could be used in all sorts of electrical equipment. 610 00:46:08,800 --> 00:46:13,080 You cannot have the electronic equipment that we have without tiny components. 611 00:46:13,080 --> 00:46:16,920 And you get a weird effect - the smaller they get, the more reliable they get, 612 00:46:16,920 --> 00:46:18,480 it's a win-win situation. 613 00:46:18,480 --> 00:46:19,760 APPLAUSE 614 00:46:20,880 --> 00:46:26,560 The Bell Labs team were awarded the Nobel Prize for their world changing invention, 615 00:46:26,560 --> 00:46:30,400 while the European team were forgotten. 616 00:46:34,520 --> 00:46:36,760 William Shockley left Bell Labs, 617 00:46:36,760 --> 00:46:42,560 and in 1955 set up his own semi-conductor Laboratory in rural California, 618 00:46:42,560 --> 00:46:47,160 recruiting the country's best physics graduates. 619 00:46:47,160 --> 00:46:49,680 But the celebratory mood didn't last long, 620 00:46:49,680 --> 00:46:54,200 because Shockley was almost impossible to work for. 621 00:46:54,200 --> 00:46:59,760 People left his company because they just disliked the way he treated them. 622 00:46:59,760 --> 00:47:04,240 So, the fact that Shockley was actually such a git 623 00:47:04,240 --> 00:47:07,040 is why you have Silicon Valley. 624 00:47:07,040 --> 00:47:12,440 It starts that whole process of spin-off and growth and new companies, 625 00:47:12,440 --> 00:47:17,280 and it all starts off with Shockley being such a shocking human being. 626 00:47:28,040 --> 00:47:30,800 The new companies were in competition with each other 627 00:47:30,800 --> 00:47:34,240 to come up with the latest semi-conductor devices. 628 00:47:34,240 --> 00:47:36,960 They made transistors so small 629 00:47:36,960 --> 00:47:41,440 that huge numbers of them could be incorporated into an electrical circuit 630 00:47:41,440 --> 00:47:45,120 printed on a single slice of semi-conductor crystal. 631 00:47:49,440 --> 00:47:55,280 These tiny and reliable chips could be used in all sorts of electrical equipment... 632 00:47:55,280 --> 00:47:58,480 most famously in computers. 633 00:47:58,480 --> 00:48:01,000 A new age had dawned. 634 00:48:11,000 --> 00:48:14,640 Today, microchips are everywhere. 635 00:48:14,640 --> 00:48:18,520 They've transformed almost every aspect of modern life, 636 00:48:18,520 --> 00:48:22,280 from communication to transport and entertainment. 637 00:48:23,560 --> 00:48:25,960 But, perhaps, just as importantly, 638 00:48:25,960 --> 00:48:28,720 our computers have become so powerful 639 00:48:28,720 --> 00:48:33,400 they're helping us to understand the universe in all its complexity. 640 00:48:36,800 --> 00:48:40,240 A single microchip like this one today 641 00:48:40,240 --> 00:48:45,000 can contain around four billion transistors. 642 00:48:45,000 --> 00:48:49,720 It's incredible how far technology has come in 60 years. 643 00:48:53,000 --> 00:48:56,120 It's easy to think that with the great leaps we've made 644 00:48:56,120 --> 00:48:58,840 in understanding and exploiting electricity, 645 00:48:58,840 --> 00:49:02,640 there's little left to learn about it. 646 00:49:02,640 --> 00:49:04,760 But we'd be wrong. 647 00:49:06,360 --> 00:49:10,960 For instance, making the circuits smaller and smaller 648 00:49:10,960 --> 00:49:16,440 meant that a particular feature of electricity that had been known about for over a century 649 00:49:16,440 --> 00:49:19,080 was becoming more and more problematic. 650 00:49:19,080 --> 00:49:20,560 Resistance. 651 00:49:23,840 --> 00:49:27,360 A computer chip has to be continuously cooled. 652 00:49:27,360 --> 00:49:29,880 If you take away the fan, this is what happens. 653 00:49:33,120 --> 00:49:34,560 Wow! That's shooting up! 654 00:49:34,560 --> 00:49:37,680 100, 120, 130 degrees... 655 00:49:42,560 --> 00:49:46,480 ..200 degrees, and it cut out. 656 00:49:46,480 --> 00:49:50,240 That just took a few seconds and the chip is well and truly cooked. 657 00:49:50,240 --> 00:49:54,120 You see, as the electrons flow through the chip, 658 00:49:54,120 --> 00:49:56,760 they're not just travelling around unimpeded. 659 00:49:56,760 --> 00:49:59,160 They're bumping into the atoms of silicone, 660 00:49:59,160 --> 00:50:04,120 and the energy being lost by these electrons is producing heat. 661 00:50:05,120 --> 00:50:07,560 Now, sometimes this was useful. 662 00:50:07,560 --> 00:50:11,080 Inventors made electric heaters and ovens, 663 00:50:11,080 --> 00:50:13,680 and whenever they got something to glow white-hot, 664 00:50:13,680 --> 00:50:15,680 well, that's a light bulb. 665 00:50:15,680 --> 00:50:18,680 But resistance in electronic apparatus, 666 00:50:18,680 --> 00:50:20,200 and in power lines, 667 00:50:20,200 --> 00:50:21,880 is the major waste of energy 668 00:50:21,880 --> 00:50:24,560 and a huge problem. 669 00:50:29,200 --> 00:50:35,640 It's thought that resistance wastes up to 20% of all the electricity we generate. 670 00:50:35,640 --> 00:50:40,200 It's one of the greatest problems of modern times. 671 00:50:40,200 --> 00:50:45,240 And the search is on for a way to solve the problem of resistance. 672 00:50:50,680 --> 00:50:52,640 What we think of as temperature 673 00:50:52,640 --> 00:50:58,720 is really a measure of how much the atoms in a material are vibrating. 674 00:50:58,720 --> 00:51:00,600 And if the atoms are vibrating, 675 00:51:00,600 --> 00:51:02,880 then electrons flowing through 676 00:51:02,880 --> 00:51:05,320 are more likely to bump into them. 677 00:51:05,320 --> 00:51:07,600 So, in general, the hotter the material, 678 00:51:07,600 --> 00:51:10,000 the higher its electrical resistance, 679 00:51:10,000 --> 00:51:11,440 and the cooler it is, 680 00:51:11,440 --> 00:51:13,280 the lower the resistance. 681 00:51:13,280 --> 00:51:15,960 But what happens if you cool something right down, 682 00:51:15,960 --> 00:51:18,600 close to absolute zero, 683 00:51:18,600 --> 00:51:22,640 -273 degrees Celsius? 684 00:51:22,640 --> 00:51:24,600 Well, at absolute zero, 685 00:51:24,600 --> 00:51:26,400 there's no heat at all, 686 00:51:26,400 --> 00:51:29,320 and so the atoms aren't moving at all. 687 00:51:29,320 --> 00:51:32,280 What happens then to the flow of electricity? 688 00:51:32,280 --> 00:51:34,680 The flow of electrons? 689 00:51:37,680 --> 00:51:42,160 Using a special device called a cryostat, 690 00:51:42,160 --> 00:51:45,920 that can keep things close to absolute zero, we can find out. 691 00:51:45,920 --> 00:51:49,080 Inside this cryostat, 692 00:51:49,080 --> 00:51:50,600 in this coil, is mercury, 693 00:51:50,600 --> 00:51:52,120 the famous liquid metal. 694 00:51:52,120 --> 00:51:55,160 And it forms part of an electric circuit. 695 00:51:55,160 --> 00:51:59,520 Now, this equipment here measures the resistance in the mercury, 696 00:51:59,520 --> 00:52:02,800 but look what happens as I lower the mercury 697 00:52:02,800 --> 00:52:06,640 into the coldest part of the cryostat. 698 00:52:09,160 --> 00:52:11,000 There it is. 699 00:52:11,000 --> 00:52:13,680 The resistance has dropped to absolutely nothing. 700 00:52:13,680 --> 00:52:16,960 Mercury, like many substances we now know, 701 00:52:16,960 --> 00:52:18,640 have this property. 702 00:52:18,640 --> 00:52:20,880 It's called "becoming super conducting", 703 00:52:20,880 --> 00:52:25,240 which means they have no resistance at all to the flow of electricity. 704 00:52:26,400 --> 00:52:29,080 But these materials only work 705 00:52:29,080 --> 00:52:32,040 when they're very, very cold. 706 00:52:32,040 --> 00:52:37,360 If we could use a superconducting material in our power cables, 707 00:52:37,360 --> 00:52:39,320 and in our electronic apparatus, 708 00:52:39,320 --> 00:52:44,720 we'd avoid losing so much of our precious electrical energy through resistance. 709 00:52:47,840 --> 00:52:51,120 The problem, of course, is that superconductors had to be kept 710 00:52:51,120 --> 00:52:54,080 at extremely low temperatures. 711 00:52:54,080 --> 00:52:57,240 Then, in 1986, 712 00:52:57,240 --> 00:52:58,840 a breakthrough was made. 713 00:53:01,760 --> 00:53:04,920 In a small laboratory near Zurich, Switzerland, 714 00:53:04,920 --> 00:53:09,520 IBM physicists recently discovered superconductivity in a new class of materials 715 00:53:09,520 --> 00:53:13,880 that is being called one of the most important scientific breakthroughs in many decades. 716 00:53:15,840 --> 00:53:21,040 This is a block of the same material made by the researchers in Switzerland. 717 00:53:21,040 --> 00:53:23,160 It doesn't look very remarkable, 718 00:53:23,160 --> 00:53:25,680 but if you cool it down with liquid nitrogen, 719 00:53:25,680 --> 00:53:28,280 something special happens. 720 00:53:28,280 --> 00:53:31,080 It becomes a superconductor, 721 00:53:31,080 --> 00:53:35,440 and because electricity and magnetism are so tightly linked, 722 00:53:35,440 --> 00:53:38,600 that gives it equally extraordinary magnetic properties. 723 00:53:40,040 --> 00:53:42,360 This magnet is suspended, 724 00:53:42,360 --> 00:53:45,280 levitating above the superconductor. 725 00:53:47,680 --> 00:53:51,640 The exciting thing is, that although cold, 726 00:53:51,640 --> 00:53:55,600 this material is way above absolute zero. 727 00:54:05,400 --> 00:54:08,440 These magnetic fields are so strong 728 00:54:08,440 --> 00:54:12,120 that not only can they support the weight of this magnet, 729 00:54:12,120 --> 00:54:14,640 but they should also support MY weight. 730 00:54:14,640 --> 00:54:17,080 I'm about to be levitated. 731 00:54:19,240 --> 00:54:22,400 Oh, it's a very, very strange sensation. 732 00:54:26,040 --> 00:54:29,720 When this material was first discovered in 1986, 733 00:54:29,720 --> 00:54:31,640 it created a revolution. 734 00:54:31,640 --> 00:54:35,880 Not only had no-one considered that it might be superconducting, 735 00:54:35,880 --> 00:54:41,360 but it was doing so at a temperature much warmer than anyone had thought possible. 736 00:54:41,360 --> 00:54:45,400 We are tantalisingly close to getting room temperature superconductors. 737 00:54:45,400 --> 00:54:46,800 We're not there yet, 738 00:54:46,800 --> 00:54:49,360 but one day, a new material will be found. 739 00:54:49,360 --> 00:54:52,320 And when we put that into our electronics equipment, 740 00:54:52,320 --> 00:54:56,120 we could build a cheaper, better, more sustainable world. 741 00:54:58,120 --> 00:55:02,640 Today, materials have been produced that exhibit this phenomenon 742 00:55:02,640 --> 00:55:06,320 at the sort of temperatures you get in your freezer. 743 00:55:06,320 --> 00:55:11,480 But these new superconductors can't be fully explained by the theoreticians. 744 00:55:11,480 --> 00:55:13,960 So without a complete understanding, 745 00:55:13,960 --> 00:55:17,440 experimentalists are often guided as much by luck 746 00:55:17,440 --> 00:55:20,240 as they are by a proper scientific understanding. 747 00:55:22,200 --> 00:55:25,800 Recently, a laboratory in Japan held a party 748 00:55:25,800 --> 00:55:28,600 in which they ended up dosing their superconductors 749 00:55:28,600 --> 00:55:30,600 with a range of alcoholic beverages. 750 00:55:31,760 --> 00:55:34,760 Unexpectedly, they found that red wine 751 00:55:34,760 --> 00:55:38,240 improves the performance of the superconductors. 752 00:55:40,480 --> 00:55:42,400 Electrical research 753 00:55:42,400 --> 00:55:45,160 now has the potential, once again, 754 00:55:45,160 --> 00:55:47,640 to revolutionise our world, 755 00:55:47,640 --> 00:55:51,880 IF room temperature superconductors can be found. 756 00:56:02,120 --> 00:56:06,400 Our addiction to electricity's power is only increasing. 757 00:56:06,400 --> 00:56:11,120 And when we fully understand how to exploit superconductors, 758 00:56:11,120 --> 00:56:14,720 a new electrical world will be upon us. 759 00:56:14,720 --> 00:56:20,560 It's going to lead to one of the most exciting periods of human discovery and invention, 760 00:56:20,560 --> 00:56:24,880 a brand-new set of tools, techniques and technologies 761 00:56:24,880 --> 00:56:27,640 to once again transform the world. 762 00:56:35,160 --> 00:56:38,400 Electricity has changed our world. 763 00:56:38,400 --> 00:56:43,880 Only a few hundred years ago, it was seen as a mysterious and magical wonder. 764 00:56:44,920 --> 00:56:51,920 Then, it leapt out of the laboratory with a series of strange and wondrous experiments, 765 00:56:51,920 --> 00:56:54,760 eventually being captured and put to use. 766 00:56:56,640 --> 00:56:58,720 It revolutionised communication, 767 00:56:58,720 --> 00:57:00,040 first through cables, 768 00:57:00,040 --> 00:57:04,400 and then as waves through electricity's far-reaching fields. 769 00:57:06,200 --> 00:57:09,640 It powers and lights the modern world. 770 00:57:09,640 --> 00:57:13,360 Today, we can hardly imagine life without electricity. 771 00:57:13,360 --> 00:57:15,560 It defines our era, 772 00:57:15,560 --> 00:57:18,480 and we'd be utterly lost without it. 773 00:57:21,000 --> 00:57:23,800 And yet, it still offers us more. 774 00:57:23,800 --> 00:57:28,440 We stand, once again, at the beginning of a new age of discovery, 775 00:57:28,440 --> 00:57:29,960 a new revolution. 776 00:57:36,960 --> 00:57:38,920 But above all else, 777 00:57:38,920 --> 00:57:43,920 there's one thing that all those who deal in the science of electricity know - 778 00:57:43,920 --> 00:57:46,920 its story is not over yet. 779 00:58:05,560 --> 00:58:08,720 To find out more about the story of electricity, 780 00:58:08,720 --> 00:58:11,360 and to put your power knowledge to the test, 781 00:58:11,360 --> 00:58:15,560 try the Open University's interactive energy game. 782 00:58:15,560 --> 00:58:20,200 Go to: 783 00:58:20,200 --> 00:58:22,640 ..and follow links to the Open University. 784 00:58:44,600 --> 00:58:47,760 Subtitles by Red Bee Media Ltd 785 00:58:47,760 --> 00:58:51,120 E-mail subtitling@bbc.co.uk