1 00:00:06,160 --> 00:00:11,280 In 1869, a wild-haired Russian chemist had an extraordinary vision. 2 00:00:14,400 --> 00:00:16,320 He'd been struggling with a mystery 3 00:00:16,320 --> 00:00:19,120 that had perplexed scientists for generations. 4 00:00:21,920 --> 00:00:26,080 And for the very first time, he'd glimpsed nature's building blocks, 5 00:00:26,280 --> 00:00:29,360 the elements, arranged in their natural order. 6 00:00:30,800 --> 00:00:33,360 His name was Dmitri Mendeleev, 7 00:00:33,360 --> 00:00:38,680 and he was on the brink of cracking the secret code of the Cosmos, 8 00:00:38,680 --> 00:00:43,600 what was to become one of man's most beautiful creations, 9 00:00:43,600 --> 00:00:46,440 the Periodic Table of Elements. 10 00:00:49,760 --> 00:00:51,720 This is the story of those elements, 11 00:00:51,720 --> 00:00:54,560 the building blocks that make up the universe... 12 00:00:55,800 --> 00:00:58,800 ..the remarkable tale of their discovery, 13 00:00:58,800 --> 00:01:03,840 and how they fit together, reveals how the modern world was made. 14 00:01:06,360 --> 00:01:07,920 'My name's Jim Al-Khalili. 15 00:01:07,920 --> 00:01:11,280 And ever since I started studying the mysteries of matter, 16 00:01:11,280 --> 00:01:16,240 'I've been fascinated by chemistry's explosive history...' 17 00:01:16,240 --> 00:01:18,080 Ho-ho! Brilliant! 18 00:01:18,880 --> 00:01:21,840 '..I've discovered some exciting elements...' 19 00:01:21,840 --> 00:01:23,800 That's fantastic! 20 00:01:23,800 --> 00:01:27,560 '..and I've seen how chemistry was forged 21 00:01:27,560 --> 00:01:30,720 'in the furnaces of the alchemists. 22 00:01:30,720 --> 00:01:33,640 'Now I'm going to continue my journey. 23 00:01:36,920 --> 00:01:41,480 'I'll take up the quest of the chemical pioneers...' 24 00:01:41,480 --> 00:01:43,080 Well, my arm's burning up. 25 00:01:43,080 --> 00:01:47,320 '...as they struggled to make sense of elemental chaos 26 00:01:47,320 --> 00:01:51,040 'and conquer our fundamental fear of disorder. 27 00:01:51,040 --> 00:01:56,320 'Could there be a grand plan underlying the elements? 28 00:01:57,840 --> 00:02:00,880 'I'll take part in some volatile experiments...' 29 00:02:00,880 --> 00:02:04,200 Now we're going to drop in the potassium. 30 00:02:04,200 --> 00:02:07,040 Wow, look at that! Wahey! 31 00:02:07,040 --> 00:02:11,160 '..and witness some fiery reactions.' 32 00:02:11,160 --> 00:02:15,800 And I'll find out how the hidden order of the natural world 33 00:02:15,800 --> 00:02:21,040 was revealed in all its glory - the order of the elements. 34 00:02:41,960 --> 00:02:43,320 As a nuclear physicist, 35 00:02:43,320 --> 00:02:46,400 I've spent a lifetime studying the sub-atomic world, 36 00:02:46,400 --> 00:02:49,000 the basic building blocks of matter. 37 00:02:49,000 --> 00:02:53,240 But to do that, I need to understand the ingredients of OUR world... 38 00:02:54,760 --> 00:02:57,040 ..the elements. 39 00:02:57,040 --> 00:03:01,960 Our planet was created from just 92 elements. 40 00:03:01,960 --> 00:03:08,640 The ground we walk on, the air that we breathe, the stars we gaze at, 41 00:03:08,640 --> 00:03:10,520 even us. 42 00:03:12,360 --> 00:03:15,960 Our bodies are entirely made of elements. 43 00:03:17,880 --> 00:03:20,080 We now know the name and number 44 00:03:20,080 --> 00:03:24,160 of every naturally-occurring element in existence. 45 00:03:24,160 --> 00:03:25,320 But 200 years ago, 46 00:03:25,320 --> 00:03:29,680 those elements were only just beginning to give up their secrets. 47 00:03:32,840 --> 00:03:35,200 At the beginning of the 19th century, 48 00:03:35,200 --> 00:03:37,080 only 55 had been discovered, 49 00:03:37,080 --> 00:03:42,760 from liquid mercury to dazzling magnesium... 50 00:03:44,280 --> 00:03:46,840 ..and volatile iodine. 51 00:03:50,240 --> 00:03:54,360 Scientists had no idea how many more they might find, 52 00:03:54,360 --> 00:03:57,920 or whether there could be an infinite number. 53 00:04:01,200 --> 00:04:05,840 But the big question was, how did they fit together? 54 00:04:05,840 --> 00:04:07,760 Were they random stars, 55 00:04:07,760 --> 00:04:11,880 or was the elemental world born of order and logic? 56 00:04:19,440 --> 00:04:23,760 Solving the puzzle would prove to be a daunting challenge. 57 00:04:23,760 --> 00:04:29,360 And the first glimmerings of an answer came from an unlikely source. 58 00:04:31,840 --> 00:04:35,760 John Dalton was an intelligent, modest man, 59 00:04:35,760 --> 00:04:40,200 and he had one very British passion - the weather. 60 00:04:40,200 --> 00:04:45,800 He was born here in the Lake District in 1766. 61 00:04:45,800 --> 00:04:49,440 He was so clever, that as a young boy, just 12 years old, 62 00:04:49,440 --> 00:04:54,560 he was already teaching other kids at a school that he set up. 63 00:04:54,560 --> 00:04:57,720 Walking home, he loved watching the weather systems 64 00:04:57,720 --> 00:04:59,400 sweeping across the fells. 65 00:05:04,240 --> 00:05:10,520 He was so obsessed that he kept a meteorological diary for 57 years, 66 00:05:10,520 --> 00:05:13,800 and every single day, come rain or shine, 67 00:05:13,800 --> 00:05:19,920 he entered his precise observations - 200,000 of them. 68 00:05:30,680 --> 00:05:36,320 Dalton was a quiet, retiring man with modest habits. 69 00:05:41,400 --> 00:05:46,880 He was a lifelong bachelor, with not much in the way of a social life. 70 00:05:46,880 --> 00:05:50,280 His only recreation was a game of bowls once a week, 71 00:05:50,280 --> 00:05:52,200 every Thursday afternoon. 72 00:05:55,080 --> 00:05:57,800 He was certainly a creature of habit, 73 00:05:57,800 --> 00:05:59,960 and he might sound a bit dull. 74 00:05:59,960 --> 00:06:04,640 But actually, Dalton was an avid reader and a deep thinker. 75 00:06:04,640 --> 00:06:07,600 Underneath his mild-mannered exterior, 76 00:06:07,600 --> 00:06:10,440 his head was teeming with radical ideas. 77 00:06:17,880 --> 00:06:21,400 Now scientists had recently discovered something very important 78 00:06:21,400 --> 00:06:25,040 about the way elements combine to form compounds. 79 00:06:25,040 --> 00:06:29,000 When they do so, they always combine in the same proportions. 80 00:06:29,000 --> 00:06:33,640 Dalton would have known that table salt, sodium chloride, 81 00:06:33,640 --> 00:06:38,760 is always made up of one part sodium and one part chlorine. 82 00:06:38,760 --> 00:06:42,200 So it doesn't matter whether the salt comes from Salt Lake City 83 00:06:42,200 --> 00:06:48,000 or Siberia, it's always in the same proportion by weight, every time. 84 00:06:48,000 --> 00:06:50,440 Dalton reckoned for this to happen, 85 00:06:50,440 --> 00:06:55,840 each element had to be made up of its own unique building blocks, 86 00:06:55,840 --> 00:06:59,640 what he called "ultimate particles", atoms. 87 00:07:02,920 --> 00:07:07,280 It was a blinding illumination, completely left field. 88 00:07:07,280 --> 00:07:11,360 Everything, he suggested, the entire universe, 89 00:07:11,360 --> 00:07:15,440 was made up of infinitesimally small particles. 90 00:07:18,480 --> 00:07:22,840 The Greeks had hit on the idea of the atom 2,000 years earlier, 91 00:07:22,840 --> 00:07:24,640 but abandoned it. 92 00:07:24,640 --> 00:07:29,800 Now, Dalton took up the baton with his own theory of matter. 93 00:07:32,600 --> 00:07:36,000 What Dalton was describing was revolutionary. 94 00:07:36,000 --> 00:07:38,960 He had struck on the foundations of atomic theory, 95 00:07:38,960 --> 00:07:44,080 foreshadowing research that wouldn't be proved until a century later. 96 00:07:44,080 --> 00:07:47,480 He proposed that there are as many kinds of atoms 97 00:07:47,480 --> 00:07:49,160 as there are elements. 98 00:07:49,160 --> 00:07:51,200 And just as each element is different, 99 00:07:51,200 --> 00:07:55,280 so each element's atom has a different weight - 100 00:07:55,280 --> 00:07:57,480 a unique atomic weight. 101 00:08:05,240 --> 00:08:09,560 Every element has its own signature atomic weight, 102 00:08:09,560 --> 00:08:13,320 whether it be a solid, a liquid, or even a gas. 103 00:08:13,320 --> 00:08:17,280 These three balloons are each filled with a different gas. 104 00:08:17,280 --> 00:08:19,280 Now they are roughly the same size, 105 00:08:19,280 --> 00:08:22,520 so they should each have about the same number of atoms in. 106 00:08:22,520 --> 00:08:26,400 Dalton reckoned that different atoms have different atomic weights. 107 00:08:26,400 --> 00:08:29,800 So these three balloons should each weigh different amounts. 108 00:08:29,800 --> 00:08:34,800 So this red balloon is filled with helium gas. 109 00:08:34,800 --> 00:08:36,520 And if I release it, 110 00:08:36,520 --> 00:08:37,640 it floats. 111 00:08:37,640 --> 00:08:39,840 Helium is very light. 112 00:08:43,600 --> 00:08:47,840 This second balloon is filled with argon gas. 113 00:08:47,840 --> 00:08:49,760 And if I release it, 114 00:08:49,760 --> 00:08:51,040 it sinks slowly. 115 00:08:51,040 --> 00:08:53,240 Argon is heavier than helium. 116 00:08:56,720 --> 00:09:00,520 The third balloon is filled with krypton gas. And if I let it go, 117 00:09:00,520 --> 00:09:03,520 it falls like a stone. 118 00:09:03,520 --> 00:09:05,560 So Dalton was on the right lines - 119 00:09:05,560 --> 00:09:09,880 different atoms of different elements have different weights. 120 00:09:14,480 --> 00:09:18,360 Based on this theory, and working completely alone, 121 00:09:18,360 --> 00:09:21,040 Dalton made one of the first attempts 122 00:09:21,040 --> 00:09:26,440 to impose some order on the unruly world of the elements. 123 00:09:26,440 --> 00:09:31,960 This wonderfully mystical set of symbols is Dalton's line-up 124 00:09:31,960 --> 00:09:35,200 of the elements arranged by weight. 125 00:09:35,200 --> 00:09:39,040 Now there are some elements here that I don't even recognise, 126 00:09:39,040 --> 00:09:41,520 but he does start with hydrogen at one. 127 00:09:41,520 --> 00:09:45,720 Then you go down to oxygen at seven, 128 00:09:45,720 --> 00:09:49,480 and all the way down to mercury at 167. 129 00:09:50,480 --> 00:09:54,800 As it turned out, Dalton didn't get all of his weights right. 130 00:09:54,800 --> 00:09:58,520 But he had made a huge theoretical leap 131 00:09:58,520 --> 00:10:02,000 working purely from his mind's eye. 132 00:10:03,520 --> 00:10:05,160 Two hundred years ago, 133 00:10:05,160 --> 00:10:09,200 John Dalton was using his imagination as a microscope. 134 00:10:09,200 --> 00:10:14,080 But today, we have the technology to see the contours of individual atoms 135 00:10:14,080 --> 00:10:17,760 with this scanning tunnelling microscope. 136 00:10:17,760 --> 00:10:22,400 It's not like a normal microscope because it doesn't use light. 137 00:10:22,400 --> 00:10:25,680 Atoms are less than one millionth of a millimetre across, 138 00:10:25,680 --> 00:10:28,920 which is smaller than the wavelength of visible light. 139 00:10:28,920 --> 00:10:31,480 This microscope uses electrons 140 00:10:31,480 --> 00:10:34,520 to scan across the surface of materials, 141 00:10:34,520 --> 00:10:37,280 picking out individual atoms. 142 00:10:40,840 --> 00:10:44,200 The images it produces are striking. 143 00:10:45,720 --> 00:10:49,440 These are atoms of shining silicon. 144 00:10:49,440 --> 00:10:53,560 These are carbon atoms. 145 00:10:53,560 --> 00:10:57,040 This is what gold atoms look like. 146 00:10:57,040 --> 00:11:00,600 And these are atoms of copper. 147 00:11:05,640 --> 00:11:10,080 Copper is a lustrous metal, essential for life. 148 00:11:10,080 --> 00:11:16,640 It fuelled the move out of the Stone Age into the Bronze Age. 149 00:11:18,760 --> 00:11:22,400 Copper nuggets can be found on the earth's surface, 150 00:11:22,400 --> 00:11:25,720 but it usually needs to be extracted from ores. 151 00:11:25,720 --> 00:11:30,920 And copper compounds run in the veins of some animals. 152 00:11:30,920 --> 00:11:37,200 The blood of the octopus is blue, along with snails, and spiders. 153 00:11:41,120 --> 00:11:44,520 John Dalton's idea in the early 1800s, 154 00:11:44,520 --> 00:11:47,680 that elements had different atomic weights, 155 00:11:47,680 --> 00:11:51,200 was dismissed by many scientists. 156 00:11:51,200 --> 00:11:54,360 But one man believed in him - 157 00:11:54,360 --> 00:11:57,640 Swedish chemist Jons Jakob Berzelius. 158 00:11:59,240 --> 00:12:04,400 Berzelius was obsessed with imposing some kind of order on the elements. 159 00:12:04,400 --> 00:12:08,880 He was convinced that knowing more about the weight of each element 160 00:12:08,880 --> 00:12:11,080 was somehow vitally important. 161 00:12:11,080 --> 00:12:14,120 And when he heard about Dalton's theory, 162 00:12:14,120 --> 00:12:16,640 he came up with an ambitious plan. 163 00:12:16,640 --> 00:12:19,000 It was a gargantuan task. 164 00:12:19,000 --> 00:12:20,960 In fact, it seems almost mad. 165 00:12:20,960 --> 00:12:23,520 This lone Swedish chemist set out 166 00:12:23,520 --> 00:12:28,560 to measure precisely the atomic weight of every single element, 167 00:12:28,560 --> 00:12:31,760 and this without a shred of proof that atoms even existed. 168 00:12:31,760 --> 00:12:37,240 But before Berzelius could start, he was going to have to purify, 169 00:12:37,240 --> 00:12:41,000 dilute, filter each element incredibly accurately. 170 00:12:41,000 --> 00:12:44,160 And that was far from straightforward. 171 00:12:44,160 --> 00:12:45,520 At the time, 172 00:12:45,520 --> 00:12:48,760 very little of the crucial chemical apparatus 173 00:12:48,760 --> 00:12:52,720 needed for work of this precision had even been invented. 174 00:12:52,720 --> 00:12:56,200 But that wasn't going to stop a man like Berzelius. 175 00:12:56,200 --> 00:12:57,800 He was on a mission. 176 00:12:59,080 --> 00:13:02,440 So Berzelius set out to make his own lab equipment. 177 00:13:03,400 --> 00:13:07,200 Ah, Liam. Hi, Jim. Nice to meet you. Come through to the hotshop. 178 00:13:07,200 --> 00:13:09,920 'Liam Reeves, a professional glassblower 179 00:13:10,760 --> 00:13:14,280 'at the Royal College of Art will show me how Berzelius did it. 180 00:13:21,560 --> 00:13:23,920 'Glassblowing is physically demanding, 181 00:13:23,920 --> 00:13:27,160 'and calls for working at punishingly high temperatures. 182 00:13:27,160 --> 00:13:29,600 'Berzelius must have been very dedicated.' 183 00:13:29,600 --> 00:13:31,800 I'm getting the glass out now, 184 00:13:31,800 --> 00:13:35,280 which is at about 1,000 degrees centigrade. 185 00:13:39,040 --> 00:13:43,600 I'm using a wooden block just to cool and shape the glass. 186 00:13:43,600 --> 00:13:45,560 What is it you're making? 187 00:13:45,560 --> 00:13:47,440 It will be a round-bottomed flask, 188 00:13:47,440 --> 00:13:50,520 which would have been part of the basic chemistry equipment 189 00:13:51,160 --> 00:13:54,920 that Berzelius would have used. Now I'm going to introduce some air, 190 00:13:54,920 --> 00:13:57,840 which I'll trap in the pipe and the heat makes expand. 191 00:14:03,520 --> 00:14:08,040 Wow! How hard would it have been for Berzelius to learn to do this? 192 00:14:08,040 --> 00:14:11,880 They say it takes 12 years to kind of...to really master glass. 193 00:14:11,880 --> 00:14:13,800 He was a very skilled glassblower 194 00:14:13,800 --> 00:14:16,280 from the evidence that I've seen of his work. 195 00:14:16,280 --> 00:14:20,520 What he was making was high-precision apparatus, 196 00:14:20,520 --> 00:14:23,880 so that must have made it far more difficult 197 00:14:23,880 --> 00:14:26,360 than your average vase or tumbler. 198 00:14:26,360 --> 00:14:30,120 From the pictures that I've seen, I've got no idea how he made it. 199 00:14:30,120 --> 00:14:34,600 Really? Yeah. No idea. So I'm just making the top of the bottle now. 200 00:14:52,080 --> 00:14:54,560 Right, so that's a basic round-bottomed flask 201 00:14:54,560 --> 00:14:57,200 very much like one that Berzelius would have made. 202 00:14:57,200 --> 00:15:01,720 Glassblowing isn't something theoretical physicists like me 203 00:15:01,720 --> 00:15:03,080 normally do. 204 00:15:03,080 --> 00:15:05,280 But I want to find out for myself 205 00:15:05,280 --> 00:15:08,520 just how hard it is to master this new skill. 206 00:15:08,520 --> 00:15:10,440 OK, just turn a little bit slower. 207 00:15:10,440 --> 00:15:12,760 Come back ever so slightly. 208 00:15:15,040 --> 00:15:17,520 Ah! Well, my arm's burning up. 209 00:15:17,520 --> 00:15:20,160 I'll shield you, actually. Oh, that's better. 210 00:15:24,480 --> 00:15:26,000 'It's going rather well.' 211 00:15:29,520 --> 00:15:30,560 SNAP! 212 00:15:30,560 --> 00:15:32,000 Oh-h! 213 00:15:32,960 --> 00:15:34,800 Oh, well. 214 00:15:36,320 --> 00:15:39,640 That just goes to show how difficult this is. 215 00:15:39,640 --> 00:15:42,000 So it does take 12 years to do. 216 00:15:42,000 --> 00:15:45,200 I think you would have managed it in seven or eight. 217 00:15:45,200 --> 00:15:49,280 There's my flask dying slowly, melting away. 218 00:15:49,280 --> 00:15:52,360 I mean, it just goes to prove how incredibly talented 219 00:15:52,360 --> 00:15:55,560 Berzelius was - he wasn't making something basic like this, 220 00:15:55,560 --> 00:15:57,920 he was making some really intricate stuff. 221 00:15:57,920 --> 00:16:04,480 'And although he was searching for elemental order, there was a bonus.' 222 00:16:04,480 --> 00:16:08,040 The great thing, you see, about Berzelius was that the skills 223 00:16:08,040 --> 00:16:13,360 he learned as a glassblower led him to an incredible discovery. 224 00:16:13,360 --> 00:16:17,360 In 1824, he discovered a new element, 225 00:16:17,360 --> 00:16:22,240 because he found that one of the constituents of glass was silicon. 226 00:16:23,760 --> 00:16:30,200 Silicon is a semi-metallic element... found within some meteorites. 227 00:16:31,360 --> 00:16:34,680 Closer to home, it's under your feet. 228 00:16:35,720 --> 00:16:40,720 The earth's crust is made primarily of silicate minerals. 229 00:16:40,720 --> 00:16:46,360 Silicon is its second most abundant element, after oxygen. 230 00:16:46,360 --> 00:16:51,600 It's mostly found in nature as sand or quartz. 231 00:16:51,600 --> 00:16:57,920 Its man-made compounds can be heat resistant, 232 00:16:57,920 --> 00:17:01,600 water resistant and non-stick. 233 00:17:01,600 --> 00:17:06,600 But silicon's ultimate achievement has to be the silicon chip, 234 00:17:06,600 --> 00:17:11,560 shrinking computers from room size to palm size. 235 00:17:11,560 --> 00:17:16,440 Silicon was the last of four elements that Berzelius isolated, 236 00:17:16,440 --> 00:17:20,480 along with thorium, cerium, and selenium. 237 00:17:20,480 --> 00:17:23,320 He then spent the next decade of his life 238 00:17:23,320 --> 00:17:27,920 measuring atomic weight after atomic weight after atomic weight 239 00:17:27,920 --> 00:17:30,200 in an obsessive pursuit of logic 240 00:17:30,200 --> 00:17:34,680 in the face of the seemingly random chaos of the natural world. 241 00:17:38,760 --> 00:17:44,680 Berzelius laboriously studied over 2,000 chemical compounds 242 00:17:44,680 --> 00:17:47,560 with staggering dedication. 243 00:17:47,560 --> 00:17:52,840 He weighed, he measured and he agonised over the tiniest detail 244 00:17:52,840 --> 00:17:57,200 until he'd found out the relative weights of 45 different elements. 245 00:18:00,040 --> 00:18:03,480 Some of his results were remarkably accurate. 246 00:18:03,760 --> 00:18:06,480 His weight for chlorine, a gas, 247 00:18:06,480 --> 00:18:11,360 got to within a fifth of a per cent of what we know today. 248 00:18:13,360 --> 00:18:16,760 But by the time Berzelius produced his results, 249 00:18:16,760 --> 00:18:20,680 other scientists had started measuring atomic weights 250 00:18:20,680 --> 00:18:24,120 and come up with completely different answers. 251 00:18:24,120 --> 00:18:27,600 Now they were pitted against each other, 252 00:18:27,600 --> 00:18:33,040 perhaps fuelled by an innate desire to find meaning in disorder. 253 00:18:33,040 --> 00:18:37,360 Berzelius's quest for order was contagious. 254 00:18:37,360 --> 00:18:40,400 Scientists began looking for patterns everywhere. 255 00:18:42,120 --> 00:18:46,200 One of these was German chemist Johann Wolfgang Dobereiner. 256 00:18:49,280 --> 00:18:52,480 He believed that the answer lay not with atomic weights 257 00:18:52,480 --> 00:18:57,040 but with the elements' chemical properties and reactions. 258 00:18:59,840 --> 00:19:03,840 'Dr Andrea Sella has studied Dobereiner's work 259 00:19:03,840 --> 00:19:05,560 'on chemical groups.' 260 00:19:05,560 --> 00:19:09,320 What Dobereiner had really spotted was that if you considered 261 00:19:09,320 --> 00:19:11,920 all the elements that were known to that time, 262 00:19:11,920 --> 00:19:15,920 you could often pick out three - "triads", as he called them, 263 00:19:15,920 --> 00:19:19,640 which had very, very closely related chemical properties. 264 00:19:19,640 --> 00:19:23,240 And as an example, we have here the alkali metals. 265 00:19:23,240 --> 00:19:28,240 And I'm going to take the first and the lightest of them, lithium. 266 00:19:28,240 --> 00:19:30,800 And we have to store these under oil 267 00:19:30,800 --> 00:19:35,760 because they tend to react with air and moisture. So here goes lithium. 268 00:19:35,760 --> 00:19:37,440 Pop it in. 269 00:19:37,440 --> 00:19:40,480 Oh, look, fizzing away, yeah. 270 00:19:40,480 --> 00:19:44,320 You can see it fizzing. And the fizzing is hydrogen, 271 00:19:44,320 --> 00:19:46,280 flammable air, being released. 272 00:19:46,280 --> 00:19:49,320 And at the same time, it's leaving a pink trail. 273 00:19:49,320 --> 00:19:52,320 We've put a bit of indicator in there, which is telling us 274 00:19:52,320 --> 00:19:54,520 that what's left behind is caustic. 275 00:19:54,520 --> 00:19:57,160 It's actually making an alkaline solution. 276 00:19:57,160 --> 00:19:59,160 I'm breathing in some caustic soda! 277 00:19:59,160 --> 00:20:02,240 Well, you're getting a little bit of steam coming off, 278 00:20:02,240 --> 00:20:04,840 and the reaction is very, very exothermic. 279 00:20:04,840 --> 00:20:07,280 In other words, the temperature rises a lot, 280 00:20:07,280 --> 00:20:09,200 and the metal has actually melted. 281 00:20:09,200 --> 00:20:14,040 The second metal in this triad was sodium. 282 00:20:14,040 --> 00:20:16,280 And when we drop the sodium in... 283 00:20:17,960 --> 00:20:22,000 Whoa! Oh, look at that, flashes of light! 284 00:20:22,000 --> 00:20:25,600 Orange sparks. And those orange sparks are the same colour 285 00:20:25,600 --> 00:20:27,520 as what you get in streetlights. 286 00:20:27,520 --> 00:20:29,680 Streetlights have sodium in them. Right. 287 00:20:29,680 --> 00:20:34,080 Well, the third one in the series is potassium. 288 00:20:34,080 --> 00:20:36,880 The potassium turns out to be the tiger. 289 00:20:36,880 --> 00:20:39,320 And we may need to stand back. 290 00:20:39,320 --> 00:20:41,440 Look at those flashes. Wow! 291 00:20:41,440 --> 00:20:43,800 And you can see that lilac flame. 292 00:20:43,800 --> 00:20:47,160 And one could really see trends in these triads. 293 00:20:47,160 --> 00:20:49,920 They're all doing the same thing, aren't they? Yes. 294 00:20:49,920 --> 00:20:53,320 The fizzing is telling us that hydrogen is coming off. 295 00:20:53,320 --> 00:20:55,480 We're getting the alkali being formed. 296 00:20:55,480 --> 00:20:58,040 But the lithium is relatively tame, 297 00:20:58,040 --> 00:21:03,000 the sodium was more excitable, the potassium starts getting scary. 298 00:21:04,800 --> 00:21:08,800 Dobereiner realised that these elements must be a family 299 00:21:08,800 --> 00:21:11,480 because they reacted in a similar way. 300 00:21:11,480 --> 00:21:14,480 Here was the hint of a pattern. 301 00:21:14,480 --> 00:21:17,880 But it only worked on a few of the elements. 302 00:21:17,880 --> 00:21:23,120 It got scientists no further than atomic weights had done. 303 00:21:23,120 --> 00:21:27,400 The bigger picture, the universal order of all the elements, 304 00:21:27,400 --> 00:21:28,880 was still hard to see. 305 00:21:28,880 --> 00:21:32,400 And that wouldn't change until a breakthrough 306 00:21:32,400 --> 00:21:36,160 by one of greatest minds in 19th-century science. 307 00:21:40,440 --> 00:21:48,080 In 1848, in the far west of Siberia, a massive fire destroyed a factory. 308 00:21:48,080 --> 00:21:51,880 The factory manager faced destitution. 309 00:21:51,880 --> 00:21:57,680 She was a widow, Maria Mendeleeva, and she made a remarkable sacrifice 310 00:21:57,680 --> 00:22:03,760 for her precociously intelligent son, 14-year-old Dmitri Mendeleev. 311 00:22:08,840 --> 00:22:11,800 Maria was well aware of her son's intelligence, 312 00:22:11,800 --> 00:22:16,880 and with a steely determination she set out to get him an education. 313 00:22:16,880 --> 00:22:22,120 So, together with Dmitri, she set off on a 1,300-mile journey 314 00:22:22,120 --> 00:22:25,040 from Siberia to St Petersburg. 315 00:22:25,040 --> 00:22:29,120 And incredibly, they walked a good part of that journey. 316 00:22:32,880 --> 00:22:36,480 I'm following in their footsteps to St Petersburg, 317 00:22:36,480 --> 00:22:39,240 then the capital of the Russian empire. 318 00:22:42,680 --> 00:22:45,760 After their arduous journey across the Russian steppes, 319 00:22:45,760 --> 00:22:48,920 mother and son finally arrived at St Petersburg. 320 00:22:48,920 --> 00:22:52,880 Maria Mendeleeva had got what she wanted, 321 00:22:52,880 --> 00:22:54,880 but the effort destroyed her. 322 00:22:54,880 --> 00:22:57,600 She died ten weeks later. 323 00:23:03,200 --> 00:23:07,120 The story goes that her last words to her son were - 324 00:23:07,120 --> 00:23:12,880 "Refrain from illusions and seek divine and scientific truth." 325 00:23:12,880 --> 00:23:16,120 And young Mendeleev promised to obey. 326 00:23:18,000 --> 00:23:21,640 He studied day and night to fulfil his mother's dream 327 00:23:21,640 --> 00:23:26,720 and became the most brilliant chemistry student of his generation. 328 00:23:28,240 --> 00:23:32,960 Chemistry had come a long way since the Greeks' idea of four elements - 329 00:23:32,960 --> 00:23:37,120 earth, air, fire and water. 330 00:23:37,120 --> 00:23:40,120 But there was still no order to the 63 elements 331 00:23:40,120 --> 00:23:43,520 that had so far been discovered. 332 00:23:43,520 --> 00:23:49,000 Now the search for a pattern gripped some of the best minds in science. 333 00:23:49,000 --> 00:23:52,400 But no-one could agree how to find it. 334 00:23:52,400 --> 00:23:55,640 Mendeleev was still a student when he attended 335 00:23:56,280 --> 00:24:00,000 the world's first ever international chemistry conference. 336 00:24:00,000 --> 00:24:03,280 The world's chemists had gathered to settle the dispute 337 00:24:03,280 --> 00:24:09,120 that was holding back their subject, the confusion over atomic weights. 338 00:24:10,040 --> 00:24:15,120 Mendeleev watched as Sicilian chemist Stanislao Cannizzaro 339 00:24:15,120 --> 00:24:16,520 stole the show. 340 00:24:16,520 --> 00:24:18,800 Cannizzaro was still convinced 341 00:24:18,800 --> 00:24:21,960 that atomic weights held the key to the elements, 342 00:24:21,960 --> 00:24:25,240 and he'd struck on a wonderful innovation, 343 00:24:25,240 --> 00:24:28,320 a reliable new way of calculating them. 344 00:24:28,320 --> 00:24:34,400 He knew that equal volumes of gases contain equal numbers of molecules. 345 00:24:34,400 --> 00:24:37,400 So instead of working with liquids and solids, 346 00:24:37,400 --> 00:24:42,560 his breakthrough was to use the densities of gases and vapours 347 00:24:42,560 --> 00:24:46,640 to measure the atomic weights of single atoms. 348 00:24:48,160 --> 00:24:52,600 Cannizzaro gave a talk in which he presented striking new evidence 349 00:24:52,600 --> 00:24:55,200 that won over the assembled chemists. 350 00:24:55,200 --> 00:24:59,320 So whereas Berzelius's work had failed to convince anyone, 351 00:24:59,320 --> 00:25:03,720 Cannizzaro's new method set an agreed standard. 352 00:25:03,720 --> 00:25:08,960 Finally, chemists had a way of measuring atomic weights accurately. 353 00:25:12,640 --> 00:25:16,400 It was the moment everybody had been waiting for. 354 00:25:16,400 --> 00:25:19,480 Surely with precise atomic weights 355 00:25:19,480 --> 00:25:23,200 they would now be able to unravel the mystery of the elements? 356 00:25:24,840 --> 00:25:28,560 One chemist wrote, "It was as though the scales fell from my eyes 357 00:25:28,560 --> 00:25:33,480 "and doubt was replaced by peaceful clarity." 358 00:25:33,480 --> 00:25:35,840 There was a real buzz in the air. 359 00:25:35,840 --> 00:25:38,680 Finally, it seemed that the order of the elements 360 00:25:38,680 --> 00:25:40,920 may have been within science's grasp. 361 00:25:40,920 --> 00:25:43,640 Mendeleev was electrified. 362 00:25:45,600 --> 00:25:50,920 But chemists soon found that even arranged in order of atomic weight, 363 00:25:50,920 --> 00:25:53,320 the elements appeared unsystematic. 364 00:25:53,320 --> 00:25:57,280 They were still missing something vital. 365 00:25:57,280 --> 00:26:01,400 Then, in 1863, a solitary English chemist 366 00:26:01,400 --> 00:26:06,040 named John Newlands made an unusual discovery. 367 00:26:06,040 --> 00:26:10,400 Newlands noticed that when the elements are arranged by weight, 368 00:26:10,400 --> 00:26:12,840 something very strange happened. 369 00:26:15,440 --> 00:26:18,480 Imagine each element is like a key on the piano, 370 00:26:18,480 --> 00:26:20,680 arranged by their atomic weight. 371 00:26:20,680 --> 00:26:22,880 Then this will be carbon, 372 00:26:22,880 --> 00:26:24,800 followed by nitrogen, 373 00:26:24,800 --> 00:26:31,080 oxygen, fluorine, sodium, magnesium, aluminium 374 00:26:31,080 --> 00:26:34,520 and finally silicon. 375 00:26:34,520 --> 00:26:37,240 'Thinking of the elements like a musical scale, 376 00:26:37,240 --> 00:26:42,120 'Newlands reckoned that every octave, every eight notes, 377 00:26:42,120 --> 00:26:46,080 'certain properties seemed to repeat, to harmonise.' 378 00:26:48,160 --> 00:26:51,760 He called it a "law of octaves". 379 00:26:51,760 --> 00:26:55,520 It was the first real attempt to find a law of nature 380 00:26:55,520 --> 00:26:57,920 that pulled all the known elements together. 381 00:27:01,080 --> 00:27:03,800 Newlands proudly presented his idea 382 00:27:03,800 --> 00:27:08,640 to the great and the good of the Chemical Society in 1866. 383 00:27:08,640 --> 00:27:10,760 It was his big moment. 384 00:27:10,760 --> 00:27:14,680 But his music analogy didn't seem to strike a chord. 385 00:27:14,680 --> 00:27:17,880 They completely failed to see his point. 386 00:27:20,960 --> 00:27:24,920 The assembled chemists said Newlands' idea was ridiculous, 387 00:27:24,920 --> 00:27:28,360 that he might as well have arranged the elements alphabetically 388 00:27:28,360 --> 00:27:30,680 for all the insight his theory gave. 389 00:27:30,680 --> 00:27:34,080 Maybe, they even suggested with biting sarcasm, 390 00:27:34,080 --> 00:27:37,480 that Newlands could get his elements to play them a little tune. 391 00:27:39,840 --> 00:27:43,640 It must have been a shattering blow for Newlands. 392 00:27:50,720 --> 00:27:54,040 But was John Newlands really onto something 393 00:27:54,040 --> 00:27:56,520 with his curious law of octaves? 394 00:27:58,520 --> 00:28:00,480 It's such a bizarre concept 395 00:28:00,480 --> 00:28:04,000 that every eighth element will behave in a similar way. 396 00:28:04,000 --> 00:28:08,080 It's not surprising that people thought Newlands' idea was mad. 397 00:28:09,000 --> 00:28:13,840 Here are eight elements in order of their atomic weight, 398 00:28:13,840 --> 00:28:18,160 and I'm going to explore their properties by smelling them. 399 00:28:18,160 --> 00:28:21,160 The first element is chlorine. 400 00:28:21,160 --> 00:28:25,040 It's a yellowy-green gas that's highly toxic. 401 00:28:25,040 --> 00:28:27,280 If I have a sniff... 402 00:28:27,280 --> 00:28:30,400 Yep, distinctive smell of bleach. 403 00:28:30,400 --> 00:28:33,840 The second one is potassium. 404 00:28:33,840 --> 00:28:36,800 But no odour to it at all. 405 00:28:36,800 --> 00:28:40,680 'And as I smell my way through the next five elements, 406 00:28:40,680 --> 00:28:45,040 'calcium, gallium, germanium, arsenic - 407 00:28:45,040 --> 00:28:47,560 'not poisonous to smell in its pure form - 408 00:28:47,560 --> 00:28:49,800 'and selenium, there's no scent.' 409 00:28:49,800 --> 00:28:54,080 Finally number eight, bromine. 410 00:28:54,080 --> 00:28:55,720 I already see it's a gas, 411 00:28:55,720 --> 00:28:58,920 like chlorine, a reddish gas, highly toxic. 412 00:28:58,920 --> 00:29:00,440 I'm going to be very careful, 413 00:29:00,440 --> 00:29:03,760 because I don't recommend you try this at home. 414 00:29:03,760 --> 00:29:08,320 Smells very much like chlorine, only a lot worse, a lot stronger. 415 00:29:08,320 --> 00:29:12,440 And so Newlands' law of octaves seems to work here, 416 00:29:12,440 --> 00:29:15,880 because the eighth element, bromine, is similar in properties 417 00:29:15,880 --> 00:29:17,480 to the first one, chlorine. 418 00:29:19,000 --> 00:29:24,680 'Today we know Newlands' law of octaves as the law of periodicity. 419 00:29:26,200 --> 00:29:31,120 ' But at the time, the establishment scoffed. 420 00:29:31,120 --> 00:29:34,360 ' And Newlands never got over the slight. 421 00:29:35,880 --> 00:29:39,360 'The way was left clear for Dmitri Mendeleev, 422 00:29:39,360 --> 00:29:41,960 'who was thinking along the same lines.' 423 00:29:44,480 --> 00:29:48,600 I'm on my way to St Petersburg University 424 00:29:48,880 --> 00:29:53,480 to meet a man who will hopefully show me where Mendeleev actually worked. 425 00:29:56,120 --> 00:29:58,600 Hello, Professor Babaev. 426 00:29:58,600 --> 00:30:01,360 Hi, I'm Jim. Good to meet you. It's very exciting. 427 00:30:01,360 --> 00:30:05,200 OK, well, the museum... Right, well, lead on. 428 00:30:05,240 --> 00:30:10,440 'Professor Eugene Babaev is the leading expert on Mendeleev, 429 00:30:10,440 --> 00:30:14,560 'having studied his work many years. 430 00:30:14,560 --> 00:30:19,520 'He's going take me inside Mendeleev's apartment, 431 00:30:19,520 --> 00:30:23,760 'preserved just as it was during the last years of his life. 432 00:30:25,280 --> 00:30:27,480 'This is a great honour. 433 00:30:27,480 --> 00:30:31,880 'Normally, nobody is allowed inside Mendeleev's study.' 434 00:30:31,880 --> 00:30:37,400 So this is quite a privilege, to be able to come in here. 435 00:30:37,400 --> 00:30:39,880 Look at this. Fantastic. 436 00:30:39,880 --> 00:30:45,960 'Mendeleev shut himself away in this room, brooding over the elements. 437 00:30:45,960 --> 00:30:48,760 'This would become the birthplace 438 00:30:48,760 --> 00:30:54,080 'of one of science's greatest achievements, the periodic table.' 439 00:30:54,080 --> 00:30:55,720 And I love this photo of him. 440 00:30:55,720 --> 00:30:59,920 This is the photo of 1869, just the year when... Ah! 441 00:30:59,920 --> 00:31:03,720 So that's what he looked like when he came up with the periodic table. 442 00:31:03,720 --> 00:31:08,560 And these are all his original books. These are his books, written by him. 443 00:31:08,560 --> 00:31:10,000 Oh, I see. 444 00:31:10,000 --> 00:31:13,320 When I say "his books", not owned by him. 445 00:31:13,320 --> 00:31:16,280 These are the books that he wrote. Thousands of volumes. 446 00:31:16,280 --> 00:31:17,400 That's impressive. 447 00:31:17,400 --> 00:31:20,960 OK, and if you look at his library, you will be surprised, 448 00:31:20,960 --> 00:31:26,640 because maybe 10% of the books are devoted to chemistry and physics 449 00:31:26,640 --> 00:31:30,400 but everything else is economics, technics, er... 450 00:31:30,400 --> 00:31:36,360 geography, whatever. He was a polymath. 451 00:31:36,360 --> 00:31:40,080 Yes, and his second wife was a painter, 452 00:31:40,080 --> 00:31:45,760 and one portrait here in profile is just by her work. 453 00:31:47,880 --> 00:31:51,960 'Mendeleev had such a breadth of intellectual curiosity 454 00:31:51,960 --> 00:31:56,560 'he became known as the Russian Leonardo da Vinci.' 455 00:31:58,960 --> 00:32:04,160 These are the clocks which stopped at the moment of his death in 1907. 456 00:32:04,160 --> 00:32:05,840 1907, at twenty past six. Yeah. 457 00:32:05,840 --> 00:32:11,040 'It seems as if time has stood still in this room 458 00:32:11,040 --> 00:32:13,680 'for more than a century. 459 00:32:13,680 --> 00:32:17,040 'And now that I've seen the inner sanctum 460 00:32:17,040 --> 00:32:21,320 'where Mendeleev puzzled over the elements, I want to know 461 00:32:21,320 --> 00:32:26,480 'exactly how he pieced together his masterwork, the periodic table. 462 00:32:29,080 --> 00:32:33,920 'By 1869, Mendeleev had been trying to find a pattern 463 00:32:33,920 --> 00:32:36,240 'to the elements for a decade. 464 00:32:36,240 --> 00:32:40,560 'Whatever order he and the world's chemists tried to impose, 465 00:32:40,560 --> 00:32:43,840 'there were still elements that wouldn't fit. 466 00:32:43,840 --> 00:32:47,160 'A universal theory seemed out of reach. 467 00:32:47,160 --> 00:32:50,360 'But now Mendeleev hit on a new idea. 468 00:32:50,360 --> 00:32:54,200 'He made up a pack of cards and wrote an element 469 00:32:54,200 --> 00:32:57,080 'and its atomic weight on each one.' 470 00:32:57,080 --> 00:32:59,520 Strange though this might sound, 471 00:32:59,520 --> 00:33:04,320 so began the most memorable card game in the history of science. 472 00:33:04,320 --> 00:33:06,520 He called it chemical solitaire 473 00:33:06,520 --> 00:33:10,440 and began laying out cards just to see where there was a pattern, 474 00:33:10,440 --> 00:33:12,440 whether it all fitted together. 475 00:33:12,440 --> 00:33:17,080 Now, previously, chemists had grouped the elements in one of two ways, 476 00:33:17,080 --> 00:33:18,640 either by their properties, 477 00:33:18,640 --> 00:33:21,240 like those that react very strongly with water, 478 00:33:21,240 --> 00:33:24,640 or by grouping them by their atomic weight, 479 00:33:24,640 --> 00:33:28,480 which is what Berzelius and Cannizzaro had done. 480 00:33:28,480 --> 00:33:34,120 Mendeleev's great genius was to combine those two methods together. 481 00:33:49,840 --> 00:33:52,720 'The odds were stacked against him. 482 00:33:52,720 --> 00:33:56,240 'Little more than half the elements we now know about 483 00:33:56,240 --> 00:33:57,680 'had been discovered, 484 00:33:57,680 --> 00:34:01,640 ' so he was playing with an incomplete deck of cards.' 485 00:34:09,120 --> 00:34:13,680 He stayed up for three days and three nights without any sleep, 486 00:34:13,680 --> 00:34:16,600 just thinking solidly about the problem. 487 00:34:16,600 --> 00:34:18,880 Then, on the 17th of February, 488 00:34:18,880 --> 00:34:23,520 with a snowstorm raging outside, he decided to stay at home. 489 00:34:23,520 --> 00:34:28,120 He was exhausted, and he finally he dozed off. 490 00:34:31,000 --> 00:34:34,040 ' The story goes he had an extraordinary dream. 491 00:34:34,040 --> 00:34:37,920 'He saw almost all of the 63 known elements 492 00:34:37,920 --> 00:34:43,000 'arrayed in a grand table which related them together.' 493 00:34:43,000 --> 00:34:45,640 It was an incredible breakthrough. 494 00:34:45,640 --> 00:34:50,400 I can imagine Mendeleev feeling like so many other scientific pioneers. 495 00:34:50,400 --> 00:34:56,880 It's that determination, even desperation, to crack a puzzle, 496 00:34:56,880 --> 00:34:59,760 and then that eureka moment of revelation. 497 00:35:01,960 --> 00:35:07,320 Mendeleev had revealed a deep truth about the nature of our world, 498 00:35:07,320 --> 00:35:13,880 that there is a numerical pattern underlying the structure of matter. 499 00:35:13,880 --> 00:35:15,960 This is the periodic table 500 00:35:15,960 --> 00:35:17,600 as we know it today, 501 00:35:17,600 --> 00:35:18,880 and it's rooted 502 00:35:18,880 --> 00:35:21,160 in Mendeleev's discovery. 503 00:35:21,160 --> 00:35:27,280 It decodes and makes sense of the building blocks of the whole world. 504 00:35:27,280 --> 00:35:30,040 Now, although it's so familiar to us, 505 00:35:30,040 --> 00:35:34,880 it's on the wall of every chemistry lab in every school in the world, 506 00:35:34,880 --> 00:35:38,960 if you really look at it, it's actually awe inspiring. 507 00:35:40,480 --> 00:35:45,000 What's so remarkable is that it reveals the relationships 508 00:35:45,000 --> 00:35:47,200 between each and every element in order. 509 00:35:48,160 --> 00:35:52,280 Mendeleev had brilliantly combined elements' atomic weights 510 00:35:52,280 --> 00:35:54,560 and properties 511 00:35:54,560 --> 00:36:00,480 into one universal understanding of all the elements. 512 00:36:00,480 --> 00:36:01,600 Reading it across, 513 00:36:01,600 --> 00:36:06,080 the atomic weights increase step by step with every element. 514 00:36:06,080 --> 00:36:08,200 But then, looking at it vertically, 515 00:36:08,200 --> 00:36:12,040 the elements are grouped together in families of similar properties. 516 00:36:12,040 --> 00:36:18,120 So over on this side are the alkali metals, from lithium to caesium. 517 00:36:18,120 --> 00:36:21,320 And then over on the far side are the halogens, 518 00:36:21,320 --> 00:36:27,840 like poisonous chlorine, bromine and iodine, all very highly reactive. 519 00:36:27,840 --> 00:36:31,240 And alongside them at the top are the elements important for life - 520 00:36:31,240 --> 00:36:35,640 carbon, nitrogen, oxygen, all non-metals. 521 00:36:35,640 --> 00:36:38,120 But in the middle, a vast swathe, 522 00:36:38,120 --> 00:36:39,680 are all the metals, 523 00:36:39,680 --> 00:36:43,800 and there are four times as many metals as non-metals. 524 00:36:43,800 --> 00:36:45,440 Everything is ordered. 525 00:36:45,440 --> 00:36:47,280 It's a chemical landscape 526 00:36:47,280 --> 00:36:52,160 and a perfect map of the geography of the elements. 527 00:36:53,680 --> 00:36:59,280 'Intriguingly, the periodic table didn't always look like this. 528 00:36:59,280 --> 00:37:02,600 'Professor Babaev is keen to show me a copy 529 00:37:02,600 --> 00:37:05,720 'of Mendeleev's very first manuscript.' 530 00:37:05,720 --> 00:37:09,960 So, this is the first draft of Mendeleev's periodic table. 531 00:37:09,960 --> 00:37:15,280 You can see the date, 17th February 1869. And it's in his handwriting. 532 00:37:15,280 --> 00:37:19,160 I can see the crossings out, you can feel his thought processes. 533 00:37:19,160 --> 00:37:21,600 Some familiar elements here. 534 00:37:21,600 --> 00:37:25,680 I see hydrogen, the lightest element, all the way to lead. 535 00:37:25,680 --> 00:37:28,720 Yeah, yeah. Now you can see some familiar groups, 536 00:37:28,720 --> 00:37:30,720 like alkali metals, halogens. 537 00:37:30,720 --> 00:37:34,320 It's got lithium, sodium, potassium. 538 00:37:34,320 --> 00:37:37,800 It's not like the periodic table that I would be familiar with, 539 00:37:37,800 --> 00:37:39,280 it's the other way round. 540 00:37:39,280 --> 00:37:40,760 It took maybe two years 541 00:37:40,760 --> 00:37:43,320 for Mendeleev to bring it to modern form. 542 00:37:43,320 --> 00:37:46,080 But it's remarkable that this is the foundations 543 00:37:46,080 --> 00:37:48,680 of the modern periodic table. It started here. 544 00:37:53,880 --> 00:37:56,760 'Mendeleev's first draft wasn't perfect. 545 00:37:58,280 --> 00:38:03,200 'To make his table work, he had to do something astonishing. 546 00:38:03,200 --> 00:38:09,120 'He had to leave spaces for elements that were still unknown.' 547 00:38:09,120 --> 00:38:15,680 This is a copy of the first published draft of the periodic table, 548 00:38:15,680 --> 00:38:20,040 and these question marks are where Mendeleev left gaps. 549 00:38:20,040 --> 00:38:22,680 You see, he was so confident about his model 550 00:38:22,680 --> 00:38:24,880 that he wouldn't fudge the results. 551 00:38:24,880 --> 00:38:26,560 So where the model didn't work, 552 00:38:26,560 --> 00:38:30,440 he left gaps for elements that had yet to be discovered. 553 00:38:30,440 --> 00:38:33,320 So, for instance, this question mark here 554 00:38:33,320 --> 00:38:37,040 he predicted was a metal slightly heavier than its neighbour calcium. 555 00:38:37,040 --> 00:38:39,760 And here two more metals. 556 00:38:39,760 --> 00:38:42,640 One he predicted would be dark grey in colour, 557 00:38:42,640 --> 00:38:45,880 and the other would have a low melting point. 558 00:38:45,880 --> 00:38:49,120 Mendeleev had the audacity to believe 559 00:38:49,120 --> 00:38:51,440 that he would, in time, be proved right. 560 00:38:53,800 --> 00:38:57,520 It's as if Mendeleev was a chemical prophet, 561 00:38:57,520 --> 00:39:01,480 foretelling the future in a visionary interpretation 562 00:39:01,480 --> 00:39:03,000 of the laws of matter. 563 00:39:11,520 --> 00:39:16,800 But before he could claim the glory, his gaps needed explaining. 564 00:39:16,800 --> 00:39:22,440 And a new way of detecting elements was invented in 1859. 565 00:39:22,440 --> 00:39:26,640 That was thanks to Gustav Kirchhoff and his colleague, 566 00:39:26,640 --> 00:39:29,400 the man who made the Bunsen burner. 567 00:39:29,400 --> 00:39:34,520 Robert Bunsen was a wonderfully intrepid experimenter. 568 00:39:34,520 --> 00:39:36,160 How's this for dedication? 569 00:39:36,160 --> 00:39:39,800 He lost his right eye in an explosion in his lab. 570 00:39:39,800 --> 00:39:43,800 Now, he knew that when different elements burned in the flame 571 00:39:43,800 --> 00:39:45,320 of his Bunsen burner, 572 00:39:45,320 --> 00:39:48,520 wonderful colours were revealed. This one is copper. 573 00:39:53,760 --> 00:39:56,400 This one contains strontium. 574 00:40:00,320 --> 00:40:03,160 And this one is potassium. 575 00:40:09,280 --> 00:40:12,480 Bunsen wondered whether every element 576 00:40:12,480 --> 00:40:15,640 might have a unique colour signature, 577 00:40:15,640 --> 00:40:18,480 and so he and Kirchhoff set to work. 578 00:40:20,080 --> 00:40:24,440 Kirchhoff knew that when white light is shone through a prism 579 00:40:24,440 --> 00:40:28,280 it gets split up into all its spectral colours... 580 00:40:31,840 --> 00:40:33,920 ..all the colours of the rainbow, 581 00:40:33,920 --> 00:40:38,600 from red through yellow to blue and violet. 582 00:40:38,600 --> 00:40:40,960 And he came up with this. 583 00:40:40,960 --> 00:40:43,040 It's called a spectroscope. 584 00:40:43,040 --> 00:40:46,440 It has a prism in the middle 585 00:40:46,440 --> 00:40:49,160 with two telescopes on either side. 586 00:40:49,160 --> 00:40:51,920 Bunsen and Kirchhoff then worked together 587 00:40:51,920 --> 00:40:56,840 to analyse different materials using their new piece of kit. 588 00:40:56,840 --> 00:41:00,320 So they took a compound containing sodium. 589 00:41:00,320 --> 00:41:03,480 And if I heat it up in the Bunsen burner, 590 00:41:03,480 --> 00:41:08,440 the light from the sodium passes through the first telescope 591 00:41:08,440 --> 00:41:12,600 and gets split up by the prism into its spectral lines. 592 00:41:12,600 --> 00:41:16,480 They then pass through the second telescope. And if I have a look. 593 00:41:16,480 --> 00:41:18,920 Yep, I can see the two orange lines 594 00:41:18,920 --> 00:41:21,840 which are the unique spectrum of sodium. 595 00:41:21,840 --> 00:41:24,960 No other element would give that pattern. 596 00:41:24,960 --> 00:41:29,280 Using this technique, they actually discovered two new elements, 597 00:41:29,280 --> 00:41:32,440 silvery-gold caesium, and rubidium, 598 00:41:32,440 --> 00:41:37,040 so named because of the ruby-red colour of its spectrum. 599 00:41:39,120 --> 00:41:42,800 It was this same technique that was used to test 600 00:41:42,800 --> 00:41:46,200 whether Mendeleev's prediction of gaps was right. 601 00:41:49,880 --> 00:41:52,000 He'd described in meticulous detail 602 00:41:52,000 --> 00:41:55,880 an unknown element that followed aluminium in his periodic table. 603 00:41:55,880 --> 00:42:01,760 He predicted it would be a silvery metal with atomic weight 68. 604 00:42:01,760 --> 00:42:06,480 Then, in 1875, a French chemist used a spectroscope 605 00:42:06,480 --> 00:42:10,480 to identify just such an element - 606 00:42:10,480 --> 00:42:12,240 gallium. 607 00:42:14,040 --> 00:42:20,320 Gallium is a beautiful silvery-white metal, and it's relatively soft. 608 00:42:20,320 --> 00:42:24,240 Although Mendeleev predicted its existence, 609 00:42:24,240 --> 00:42:26,000 it was actually found 610 00:42:26,000 --> 00:42:31,560 by Parisian chemist Paul Emile Lecoq de Boisbaudran. 611 00:42:31,560 --> 00:42:34,960 Gallium has a very low melting point. 612 00:42:34,960 --> 00:42:40,200 And with a boiling point of 2,204 degrees centigrade, 613 00:42:40,200 --> 00:42:44,560 it's liquid over a wider range of temperatures 614 00:42:44,560 --> 00:42:46,840 than any other known substance. 615 00:42:46,840 --> 00:42:51,160 Gallium is used to make semiconductors. 616 00:42:51,160 --> 00:42:55,840 It's found in light-emitting diodes, LEDs. 617 00:42:55,840 --> 00:43:01,280 One of gallium's compounds was shown to be effective 618 00:43:01,280 --> 00:43:04,880 in attacking drug-resistant strains of malaria. 619 00:43:19,920 --> 00:43:25,720 But even though Mendeleev had left gaps for gallium and other elements, 620 00:43:25,720 --> 00:43:27,840 his table was not complete. 621 00:43:29,080 --> 00:43:32,120 There was one group that eluded him completely, 622 00:43:32,120 --> 00:43:34,800 an entirely new family of elements. 623 00:43:36,320 --> 00:43:41,680 The story of their discovery began with an other-worldly search 624 00:43:41,680 --> 00:43:44,640 for an extraterrestrial element. 625 00:43:49,000 --> 00:43:56,080 In August 1868, a total eclipse of the sun in India was the moment 626 00:43:56,080 --> 00:44:00,040 that French astronomer Pierre Janssen had been waiting for. 627 00:44:01,520 --> 00:44:05,360 He knew that it was possible to use a spectroscope 628 00:44:05,360 --> 00:44:09,160 to identify some elements in the light of the sun. 629 00:44:09,160 --> 00:44:14,280 But the intensity of sunlight meant that many elements were hidden. 630 00:44:14,280 --> 00:44:18,240 Janssen hoped to see more during a total eclipse, 631 00:44:18,240 --> 00:44:20,800 when the sun was less blinding. 632 00:44:22,320 --> 00:44:24,760 As Janssen studied the eclipse, 633 00:44:24,760 --> 00:44:28,760 he discovered a colour signature never seen before. 634 00:44:28,760 --> 00:44:30,960 He was faced with an unknown element. 635 00:44:30,960 --> 00:44:37,280 The same spectral line was confirmed by another astronomer, 636 00:44:37,280 --> 00:44:38,920 Norman Lockyer. 637 00:44:38,920 --> 00:44:42,440 He named it helium, after the Greek sun god, 638 00:44:42,440 --> 00:44:46,800 because he thought that it could only exist on the sun. 639 00:44:46,800 --> 00:44:50,760 Enter Scottish chemist William Ramsay, 640 00:44:50,760 --> 00:44:55,280 who linked extraterrestrial helium to Earth. 641 00:44:55,280 --> 00:44:59,440 Ramsay experimented with a radioactive rock called cleveite. 642 00:44:59,440 --> 00:45:02,160 By dissolving the rock in acid, 643 00:45:02,160 --> 00:45:05,840 he collected a gas with an atomic weight of 4 644 00:45:05,840 --> 00:45:11,160 and the same spectral signature that Lockyer had seen, helium. 645 00:45:13,560 --> 00:45:18,680 Helium is the second most abundant element in the universe, 646 00:45:18,680 --> 00:45:20,040 after hydrogen. 647 00:45:20,040 --> 00:45:24,360 It was one of the elements produced just after the Big Bang. 648 00:45:24,360 --> 00:45:29,960 Liquid helium is used to cool superconducting magnets 649 00:45:29,960 --> 00:45:31,760 for MRI scanners. 650 00:45:33,280 --> 00:45:37,320 Deep-sea divers rely on helium to counter the narcotic effects 651 00:45:37,320 --> 00:45:43,120 on the brain of increased nitrogen absorption. 652 00:45:43,120 --> 00:45:46,800 And it was a vital ingredient in the space race, 653 00:45:46,800 --> 00:45:50,960 used to cool hydrogen and oxygen for rocket engines. 654 00:45:53,080 --> 00:45:55,320 Before he discovered helium on Earth, 655 00:45:55,320 --> 00:46:00,840 William Ramsay had already separated a new gas from the air, argon, 656 00:46:00,840 --> 00:46:03,240 with an atomic weight of 40. 657 00:46:04,760 --> 00:46:07,680 Now Ramsay faced a puzzle. 658 00:46:07,680 --> 00:46:12,080 He realised that the new elements didn't fit the periodic table 659 00:46:12,080 --> 00:46:16,160 and suggested there must be a missing group, 660 00:46:16,160 --> 00:46:18,400 so his search began. 661 00:46:18,400 --> 00:46:24,400 He found three more gases, which he named neon, Greek for "new", 662 00:46:24,400 --> 00:46:29,040 krypton, meaning "hidden", and xenon, "stranger". 663 00:46:30,680 --> 00:46:34,240 The group became known as the noble gases 664 00:46:34,240 --> 00:46:38,200 because they were unreactive and seemed so aloof. 665 00:46:39,760 --> 00:46:45,000 This family of gases completed the rows on the periodic table. 666 00:46:47,120 --> 00:46:50,600 Now, Mendeleev may not have known about these elusive elements, 667 00:46:50,600 --> 00:46:54,760 but he'd established the unshakeable idea of elemental relationships. 668 00:46:54,760 --> 00:46:58,200 And so he made sure that there was a place on his table 669 00:46:58,200 --> 00:47:02,600 for every new element, no matter when it was discovered. 670 00:47:09,800 --> 00:47:12,520 The periodic table is a classic example 671 00:47:12,520 --> 00:47:15,480 of the scientific method at work. 672 00:47:18,280 --> 00:47:22,680 From a mass of data, Mendeleev found a pattern. 673 00:47:22,680 --> 00:47:26,440 It led him to make predictions that could be tested 674 00:47:26,440 --> 00:47:29,120 by future experiments, 675 00:47:29,120 --> 00:47:32,600 pointing the way for 20th-century scientists 676 00:47:32,600 --> 00:47:36,000 to prove him and his theory right. 677 00:47:38,640 --> 00:47:41,200 By the time he died at the age of 72, 678 00:47:41,200 --> 00:47:45,800 he was a hero in Russia and a superhero in the world of science. 679 00:47:48,680 --> 00:47:52,880 His periodic table was immortalised in stone 680 00:47:52,880 --> 00:47:56,240 here in the centre of St Petersburg, 681 00:47:56,240 --> 00:48:00,440 and he eventually had an element named after him, mendelevium, 682 00:48:00,440 --> 00:48:03,760 as well as a crater, the Mendeleev Crater, 683 00:48:03,760 --> 00:48:06,880 on the dark side of the moon... 684 00:48:11,160 --> 00:48:16,080 ..fitting tributes to a man who came from the Siberian wastelands 685 00:48:16,080 --> 00:48:20,920 to become the ultimate cartographer of the elements. 686 00:48:27,960 --> 00:48:33,280 The periodic table had finally created order out of chaos. 687 00:48:33,280 --> 00:48:37,520 But it tells us nothing about WHY our world is as it is, 688 00:48:37,520 --> 00:48:40,680 why some elements are energetic, 689 00:48:40,680 --> 00:48:45,320 others are slow, some inert, others volatile. 690 00:48:47,080 --> 00:48:49,000 It would be another 40 years 691 00:48:49,000 --> 00:48:53,880 before an entirely different branch of science came up with an answer. 692 00:48:56,000 --> 00:49:03,200 In 1909, Ernest Rutherford looked inside the atom for the first time. 693 00:49:03,200 --> 00:49:06,240 Rutherford proposed that the structure of the atom 694 00:49:06,240 --> 00:49:08,320 was like a miniature solar system, 695 00:49:08,320 --> 00:49:12,920 an overwhelmingly empty space with a few tiny electrons 696 00:49:12,920 --> 00:49:17,040 orbiting randomly around a dense, positively-charged nucleus. 697 00:49:17,040 --> 00:49:21,480 But it wasn't until Niels Bohr came along, one-time goalkeeper 698 00:49:21,480 --> 00:49:26,960 for the Danish football squad and future Nobel prize-winning physicist 699 00:49:26,960 --> 00:49:29,120 that things really kicked off. 700 00:49:30,640 --> 00:49:35,320 He suggested that the electrons orbited around the nucleus 701 00:49:35,320 --> 00:49:36,720 in fixed shells. 702 00:49:36,720 --> 00:49:41,000 And it was his idea that was to lead to the discovery that these shells 703 00:49:41,000 --> 00:49:44,880 could only accommodate a set number of electrons. 704 00:49:49,680 --> 00:49:54,600 Imagine this football pitch is an atom, a single atom of an element. 705 00:49:54,600 --> 00:49:56,720 This is the nucleus. 706 00:49:56,720 --> 00:50:00,600 If this nucleus were to scale, my nearest orbiting electrons 707 00:50:00,600 --> 00:50:05,480 would be beyond the stands, so I've scaled it down. 708 00:50:05,480 --> 00:50:08,200 Here, on the shell nearest to the nucleus, 709 00:50:08,200 --> 00:50:11,280 there can be just two electrons, then it's full. 710 00:50:13,720 --> 00:50:15,720 Here in the second shell, 711 00:50:15,720 --> 00:50:20,680 there can be eight electrons, then it's fully occupied, too. 712 00:50:22,400 --> 00:50:27,520 The third shell is happy with 18 electrons. And so it goes on. 713 00:50:27,520 --> 00:50:31,920 Outer shells can accommodate an increasing number of electrons. 714 00:50:31,920 --> 00:50:37,240 So electrons sit in discrete shells, never in-between the shells. 715 00:50:38,280 --> 00:50:43,720 Bohr's theory would explain WHY elements behave as they do. 716 00:50:43,720 --> 00:50:47,600 It turns out that it's all to do with the number of electrons 717 00:50:47,600 --> 00:50:49,240 in the outermost shell. 718 00:50:49,240 --> 00:50:54,280 So, for example, Bohr's model showed that sodium has eleven electrons - 719 00:50:54,280 --> 00:50:58,720 two here, eight here and just one in its outer shell. 720 00:50:58,720 --> 00:51:04,120 And fluorine has nine - two here and seven in its outer shell. 721 00:51:04,120 --> 00:51:06,080 To be completely stable, 722 00:51:06,080 --> 00:51:10,160 atoms like to have a full outer shell of electrons. 723 00:51:10,160 --> 00:51:13,280 So a sodium atom would like to lose an electron, 724 00:51:13,280 --> 00:51:15,880 to have a completely full outer shell, 725 00:51:15,880 --> 00:51:19,640 whereas a fluorine atom has a gap in its outer shell, 726 00:51:19,640 --> 00:51:22,880 so by gaining an electron it can complete it. 727 00:51:22,880 --> 00:51:28,040 In this way, a sodium atom and a fluorine atom can stick together 728 00:51:28,040 --> 00:51:32,120 by exchanging an electron, making sodium fluoride. 729 00:51:32,120 --> 00:51:35,320 Bohr's work and that of many other scientists 730 00:51:35,320 --> 00:51:37,480 in the early part of the 20th century 731 00:51:37,480 --> 00:51:41,320 led to an explanation of every element and every compound, 732 00:51:41,320 --> 00:51:44,920 why some elements react together to make compounds 733 00:51:44,920 --> 00:51:46,240 and why others didn't, 734 00:51:46,240 --> 00:51:49,520 why the elements had the properties that they did, 735 00:51:49,520 --> 00:51:50,440 and this in turn 736 00:51:50,440 --> 00:51:54,000 explained why the periodic table had the shape that it did. 737 00:51:55,520 --> 00:51:59,240 Mendeleev had managed to reveal a universal pattern 738 00:51:59,240 --> 00:52:02,320 without understanding why it should be so. 739 00:52:02,320 --> 00:52:06,760 To find the answer, physicists had to delve into a subatomic world 740 00:52:06,760 --> 00:52:09,640 that Mendeleev didn't even know existed. 741 00:52:13,040 --> 00:52:16,400 This work was nothing short of a triumph. 742 00:52:16,400 --> 00:52:18,560 Even Albert Einstein was impressed. 743 00:52:18,560 --> 00:52:22,000 He wrote, "This is the highest form of musicality 744 00:52:22,000 --> 00:52:24,920 "in the sphere of thought." 745 00:52:24,920 --> 00:52:29,440 But there was still one fundamental question left to answer. 746 00:52:29,440 --> 00:52:31,960 How many elements were there? 747 00:52:31,960 --> 00:52:35,320 Could there be an infinite number between hydrogen, 748 00:52:35,320 --> 00:52:37,160 with the lightest atomic weight, 749 00:52:37,160 --> 00:52:40,560 and uranium, the heaviest known element? 750 00:52:43,480 --> 00:52:48,040 In the early 20th century, a brilliant young English physicist, 751 00:52:48,040 --> 00:52:52,040 Henry Moseley, was determined to find out. 752 00:52:52,040 --> 00:52:56,880 He speculated that the secret lay within the nucleus 753 00:52:56,880 --> 00:52:59,240 at the heart of each atom. 754 00:52:59,240 --> 00:53:02,600 Moseley developed a unique way of studying atoms. 755 00:53:02,600 --> 00:53:05,320 Scientists still use a similar technique today, 756 00:53:05,320 --> 00:53:07,240 although this X-ray spectrometer 757 00:53:07,240 --> 00:53:11,120 looks a bit different to the sort of kit Moseley that would have used. 758 00:53:11,120 --> 00:53:14,880 One of the elements that he studied was copper, 759 00:53:14,880 --> 00:53:18,760 and there's a small piece of copper inside here. 760 00:53:18,760 --> 00:53:21,320 Now, behind it is a radioactive source 761 00:53:21,320 --> 00:53:25,000 that fires high-energy radiation at the copper atoms. 762 00:53:25,000 --> 00:53:27,920 Moseley knew that the nucleus of the atom 763 00:53:27,960 --> 00:53:32,080 contains positively-charged particles we call protons. 764 00:53:32,080 --> 00:53:35,080 He also knew that surrounding the nucleus 765 00:53:35,080 --> 00:53:37,640 are negatively-charged electrons. 766 00:53:37,640 --> 00:53:41,160 Now, the radiation being fired at the copper 767 00:53:41,160 --> 00:53:44,720 is knocking some of the electrons from the atoms, 768 00:53:44,720 --> 00:53:46,480 and this had the effect 769 00:53:46,480 --> 00:53:50,560 of making the atoms give off a burst of energy, an X-ray. 770 00:53:50,560 --> 00:53:53,680 And Moseley found a way of measuring it. 771 00:53:53,680 --> 00:53:55,880 He made a startling discovery. 772 00:53:55,880 --> 00:54:01,200 He found that copper atoms always give off the same amount of energy. 773 00:54:01,200 --> 00:54:04,800 On this graph, it's shown by this spike. 774 00:54:04,800 --> 00:54:07,880 And no matter how many times I repeat this experiment, 775 00:54:07,880 --> 00:54:10,640 I will always get the spike in the same position. 776 00:54:10,640 --> 00:54:12,320 It's unique to copper. 777 00:54:12,320 --> 00:54:15,120 Mosley also experimented with other elements. 778 00:54:15,120 --> 00:54:17,760 And inside this sample there are several others. 779 00:54:17,760 --> 00:54:19,880 So if I move this on to the next one, 780 00:54:19,880 --> 00:54:23,160 which is rubidium, and run this again, 781 00:54:23,160 --> 00:54:26,160 I get another spike in a different position. 782 00:54:26,160 --> 00:54:31,000 And if I move it on again to the next one, which is molybdenum, 783 00:54:31,000 --> 00:54:34,360 I see a third spike in a new position. 784 00:54:34,360 --> 00:54:38,440 Every element has its own energy signature. 785 00:54:38,440 --> 00:54:41,200 But his stroke of brilliance was to realise 786 00:54:41,200 --> 00:54:44,640 that this is related to the number of protons. 787 00:54:44,640 --> 00:54:48,240 He was the first person to measure the number of protons 788 00:54:48,240 --> 00:54:51,400 in the nucleus of an element, the atomic number. 789 00:54:58,680 --> 00:55:01,280 Atomic numbers are whole numbers, 790 00:55:01,280 --> 00:55:03,320 so, unlike atomic weights, 791 00:55:03,320 --> 00:55:06,240 there can't be any awkward fractions. 792 00:55:06,240 --> 00:55:09,440 For example, chlorine has an atomic weight 793 00:55:10,560 --> 00:55:14,520 that comes in an inconvenient half, 35.5, 794 00:55:14,520 --> 00:55:17,440 but a whole atomic number, 17. 795 00:55:17,440 --> 00:55:20,640 So Moseley realised that it's the atomic number, 796 00:55:20,640 --> 00:55:22,280 not the atomic weight, 797 00:55:22,280 --> 00:55:25,840 that determines the number and the order of the elements. 798 00:55:25,840 --> 00:55:28,640 And this is where it gets really clever. 799 00:55:28,640 --> 00:55:32,040 Because the atomic number goes up in whole numbers, 800 00:55:32,040 --> 00:55:34,200 there could be no extra elements 801 00:55:34,200 --> 00:55:36,880 between element number one, hydrogen, 802 00:55:36,880 --> 00:55:38,560 and number 92, uranium. 803 00:55:38,560 --> 00:55:42,240 92 elements is all there could be. There's just no more room. 804 00:55:44,600 --> 00:55:49,480 So Henry Moseley did the groundwork that enables us to say 805 00:55:49,480 --> 00:55:53,160 with absolute confidence that there are 92 elements, 806 00:55:53,160 --> 00:55:58,000 from hydrogen all the way to uranium. 807 00:56:00,440 --> 00:56:03,880 Mosley was just 26 when he completed his research, 808 00:56:03,880 --> 00:56:06,800 but his genius was lost tragically early. 809 00:56:08,560 --> 00:56:13,400 At the outbreak of World War I, he volunteered to fight, 810 00:56:13,400 --> 00:56:18,440 even though, as a scientist, he could have avoided joining up. 811 00:56:18,440 --> 00:56:25,600 He was killed in action aged just 27, shot through the head by a sniper. 812 00:56:27,760 --> 00:56:31,640 A colleague wrote, "In view of what he might still have accomplished, 813 00:56:31,640 --> 00:56:36,520 "his death might well have been the single most costly death 814 00:56:36,520 --> 00:56:38,760 "of the war to mankind." 815 00:56:44,680 --> 00:56:50,960 The periodic table is a wonderful fusion of chemistry and physics. 816 00:56:52,480 --> 00:56:56,600 Mendeleev and the chemists worked from the outside, 817 00:56:56,600 --> 00:56:59,720 with the chemical properties of each element, 818 00:56:59,720 --> 00:57:02,640 and the physicists worked from the inside, 819 00:57:02,640 --> 00:57:05,160 with the invisible world of the atom. 820 00:57:05,160 --> 00:57:09,440 And yet both had arrived at the same point. 821 00:57:11,400 --> 00:57:16,280 The ordered design of the natural world had finally been explained 822 00:57:17,640 --> 00:57:21,680 in a pattern of pure, intellectual beauty. 823 00:57:21,680 --> 00:57:23,640 So an era that had begun 824 00:57:23,640 --> 00:57:27,120 with scientists groping towards an understanding 825 00:57:27,120 --> 00:57:29,600 of the basic building blocks of our world 826 00:57:29,600 --> 00:57:33,440 had ended with that world entirely classified 827 00:57:33,440 --> 00:57:35,880 and made clear for all to see. 828 00:57:35,880 --> 00:57:39,040 And we never looked back. 829 00:57:45,520 --> 00:57:48,760 Next time, I'll follow in the footsteps of the chemists 830 00:57:48,760 --> 00:57:51,000 who laboured to control the elements 831 00:57:51,000 --> 00:57:54,200 and combine them into the billions of compounds 832 00:57:54,200 --> 00:57:57,200 that make up the modern world... 833 00:57:58,200 --> 00:58:00,640 ..I'll discover how modern-day alchemists 834 00:58:00,640 --> 00:58:04,400 are attempting to push at the wildest outposts 835 00:58:04,400 --> 00:58:08,720 of the periodic table to create brand-new elements, 836 00:58:08,720 --> 00:58:13,720 and I'll find out how the power of the elements was harnessed 837 00:58:13,720 --> 00:58:17,160 to release almost unimaginable forces. 838 00:58:45,200 --> 00:58:47,160 Subtitles by Red Bee Media Ltd