All language subtitles for The Modern Alchemist 1of3 Air The Elixir of Life_Subtitles01.ENG

af Afrikaans
sq Albanian
am Amharic
ar Arabic
hy Armenian
az Azerbaijani
eu Basque
be Belarusian
bn Bengali
bs Bosnian
bg Bulgarian
ca Catalan
ceb Cebuano
ny Chichewa
zh-CN Chinese (Simplified)
zh-TW Chinese (Traditional)
co Corsican
hr Croatian
cs Czech
da Danish
nl Dutch
en English
eo Esperanto
et Estonian
tl Filipino
fi Finnish
fr French
fy Frisian
gl Galician
ka Georgian
de German
el Greek
gu Gujarati
ht Haitian Creole
ha Hausa
haw Hawaiian
iw Hebrew
hi Hindi
hmn Hmong
hu Hungarian
is Icelandic
ig Igbo
id Indonesian
ga Irish
it Italian
ja Japanese
jw Javanese
kn Kannada
kk Kazakh
km Khmer
ko Korean
ku Kurdish (Kurmanji)
ky Kyrgyz
lo Lao
la Latin
lv Latvian
lt Lithuanian
lb Luxembourgish
mk Macedonian
mg Malagasy
ms Malay
ml Malayalam
mt Maltese
mi Maori
mr Marathi
mn Mongolian
my Myanmar (Burmese)
ne Nepali
no Norwegian
ps Pashto
fa Persian
pl Polish
pt Portuguese
pa Punjabi
ro Romanian
ru Russian
sm Samoan
gd Scots Gaelic
sr Serbian
st Sesotho
sn Shona
sd Sindhi
si Sinhala
sk Slovak
sl Slovenian
so Somali
es Spanish
su Sundanese
sw Swahili
sv Swedish
tg Tajik
ta Tamil
te Telugu
th Thai
tr Turkish Download
uk Ukrainian
ur Urdu
uz Uzbek
vi Vietnamese
cy Welsh
xh Xhosa
yi Yiddish
yo Yoruba
zu Zulu
or Odia (Oriya)
rw Kinyarwanda
tk Turkmen
tt Tatar
ug Uyghur
Would you like to inspect the original subtitles? These are the user uploaded subtitles that are being translated: 1 00:00:01,440 --> 00:00:04,880 The alchemists were a mysterious group of medieval scientists 2 00:00:04,880 --> 00:00:09,120 who believed their knowledge of chemistry gave them magical powers. 3 00:00:09,120 --> 00:00:13,640 They could summon fire, produce mystical potions. 4 00:00:13,640 --> 00:00:18,000 They even tried to turn metals into gold. 5 00:00:19,280 --> 00:00:24,000 Their magnificent feats enthralled kings and commoners alike. 6 00:00:24,000 --> 00:00:26,760 But they never revealed their secrets. 7 00:00:26,760 --> 00:00:28,880 By pushing the frontiers of science, 8 00:00:28,880 --> 00:00:31,720 modern chemists can perform equally impressive feats, 9 00:00:31,720 --> 00:00:33,920 and we're happy to tell you everything. 10 00:00:55,240 --> 00:00:57,520 APPLAUSE 11 00:01:05,320 --> 00:01:08,440 Chemistry gives us an understanding of the world 12 00:01:08,440 --> 00:01:11,120 that the other sciences just don't. 13 00:01:11,120 --> 00:01:14,760 It's all about how one substance interacts with another 14 00:01:14,760 --> 00:01:17,400 to give us something new. 15 00:01:17,400 --> 00:01:22,240 Thank you. Take this Christmas tree here, for instance. 16 00:01:22,240 --> 00:01:28,520 A nice, solid structure, but watch what happens when I do this. 17 00:01:30,160 --> 00:01:31,600 Whoa! 18 00:01:35,800 --> 00:01:37,400 APPLAUSE 19 00:01:44,000 --> 00:01:48,240 Well, we certainly saw that a change took place there. 20 00:01:48,240 --> 00:01:52,240 That was a flash of light, I felt a blast of heat, 21 00:01:52,240 --> 00:01:55,760 heard a whoosh of sound and then nothing was left at all. 22 00:01:55,760 --> 00:01:58,320 Trying to understand what happens 23 00:01:58,320 --> 00:02:02,280 when one thing changes into another is chemistry. 24 00:02:02,280 --> 00:02:06,040 My name is Dr Peter Wothers, and I am a chemist. 25 00:02:06,040 --> 00:02:07,360 APPLAUSE 26 00:02:10,600 --> 00:02:13,960 Now, the ancient Greeks thought that everything around them 27 00:02:13,960 --> 00:02:16,520 was made up of just four elements. 28 00:02:16,520 --> 00:02:19,680 Air, water, earth and fire. 29 00:02:19,680 --> 00:02:21,240 We see these here. 30 00:02:21,240 --> 00:02:24,440 In the next three lectures, we're going to look at what air, 31 00:02:24,440 --> 00:02:27,480 water and earth are really made up of. 32 00:02:27,480 --> 00:02:32,560 But don't worry, there will be plenty of fire in all of the lectures. 33 00:02:32,560 --> 00:02:35,560 But this brings me to one important point. 34 00:02:35,560 --> 00:02:38,840 Please do not try these experiments at home. 35 00:02:38,840 --> 00:02:41,880 By understanding the elements around us, 36 00:02:41,880 --> 00:02:44,720 the modern building blocks of science, 37 00:02:44,720 --> 00:02:47,480 we need to look at the world in a different way, 38 00:02:47,480 --> 00:02:50,960 we need to see these elements through the eyes of a chemist. 39 00:02:50,960 --> 00:02:52,480 By understanding these elements, 40 00:02:52,480 --> 00:02:56,720 we can make better materials and better medicines for our future. 41 00:02:56,720 --> 00:03:00,480 We're going to start this first lecture looking at the air. 42 00:03:00,480 --> 00:03:03,640 Now, of course, this is something that we rarely think about, 43 00:03:03,640 --> 00:03:05,880 but without it, we'd all be dead. 44 00:03:05,880 --> 00:03:08,720 But just to show you that it really is here around us 45 00:03:08,720 --> 00:03:11,440 pushing down on this, I've got a demonstration, 46 00:03:11,440 --> 00:03:14,160 but I'd like a volunteer from the audience, please. 47 00:03:14,160 --> 00:03:16,560 Right on the corner there, at the back, yes, 48 00:03:16,560 --> 00:03:19,280 would you like to come down to the front, please? 49 00:03:21,720 --> 00:03:24,760 OK. Now. What's your name, please? Xavier. Xavier. OK. 50 00:03:24,760 --> 00:03:27,200 Right. So, see this here? This is just a normal oil drum. 51 00:03:27,200 --> 00:03:30,440 It seems to be covered in a bit of rubbish. 52 00:03:30,440 --> 00:03:33,680 Hold this, give it a good whack. 53 00:03:33,680 --> 00:03:35,880 Go on, bit harder than that. OK. 54 00:03:35,880 --> 00:03:39,160 It really is quite solid, isn't it? On the top as well, maybe. OK. 55 00:03:39,160 --> 00:03:41,600 Yeah. Do you think it's pretty solid? Yeah. 56 00:03:41,600 --> 00:03:45,880 Now, watch what happens when we take the air out of this drum. 57 00:03:45,880 --> 00:03:49,120 At the moment, there is of course a scope open at the top here, 58 00:03:49,120 --> 00:03:52,560 there's air inside, air outside, but we're going to put this pump on here 59 00:03:52,560 --> 00:03:57,080 so we're now removing the air from this drum. 60 00:03:57,080 --> 00:04:01,760 OK. And... That's good. I think you should just step back. That's it. 61 00:04:01,760 --> 00:04:05,240 You stand over there. I'll stand over here. 62 00:04:05,240 --> 00:04:09,840 OK, so we're removing the air from the inside of this drum. 63 00:04:09,840 --> 00:04:12,200 To start off with, the air molecules were pushing 64 00:04:12,200 --> 00:04:17,360 against the drum, but they're also pushing from the outside as well. 65 00:04:17,360 --> 00:04:20,800 So what do you think will happen if we remove the air from inside? 66 00:04:20,800 --> 00:04:23,280 Any ideas? It will shrink. It will shrink? 67 00:04:23,280 --> 00:04:26,680 So do you think it will gradually shrink up and get smaller? 68 00:04:26,680 --> 00:04:29,080 Yeah? Well, that's a good idea. That's what we think. 69 00:04:29,080 --> 00:04:31,760 It doesn't seem to be doing very much at the moment, does it? 70 00:04:31,760 --> 00:04:33,560 So, not a lot. 71 00:04:33,560 --> 00:04:36,960 Well, supposedly, these little air molecules 72 00:04:36,960 --> 00:04:41,120 are all pushing down on this can here. We're taking... 73 00:04:41,120 --> 00:04:42,120 BANG! 74 00:04:42,120 --> 00:04:44,160 GASPING 75 00:04:52,960 --> 00:04:58,480 Come and have a look. You feel that. It is very solid, isn't it? 76 00:04:58,480 --> 00:05:00,840 Yeah. That was just the air. 77 00:05:00,840 --> 00:05:04,080 So we do forget about it, but it really is pushing down on us. 78 00:05:04,080 --> 00:05:05,600 It's quite a strong force. 79 00:05:05,600 --> 00:05:09,560 It's like there's two full-grown men standing on your shoulders. 80 00:05:09,560 --> 00:05:12,400 We don't notice it because we're used to it, we've adapted to it. 81 00:05:12,400 --> 00:05:15,240 Thank you very much. Give him a round of applause. Thank you. 82 00:05:15,240 --> 00:05:16,880 APPLAUSE 83 00:05:22,560 --> 00:05:26,200 But what about our tree? What happened to the tree? 84 00:05:26,200 --> 00:05:29,440 Well, what would the ancient Greeks have thought if they had seen that? 85 00:05:29,440 --> 00:05:33,080 What would they have made of this strange substance? 86 00:05:33,080 --> 00:05:36,160 Well, this, actually, the Greeks never saw. 87 00:05:36,160 --> 00:05:38,120 This is a substance called guncotton. 88 00:05:38,120 --> 00:05:41,240 It was only discovered around 200 years ago. 89 00:05:41,240 --> 00:05:42,680 It's quite remarkable. 90 00:05:42,680 --> 00:05:47,720 The Greeks would've said that this is changing into fire and air. 91 00:05:47,720 --> 00:05:51,800 Maybe they would've said this is made of fire and air. 92 00:05:51,800 --> 00:05:54,840 Or maybe they would've just said it's magic. 93 00:05:54,840 --> 00:05:57,320 Either way, they would be wrong. 94 00:05:57,320 --> 00:06:00,680 We now know that the air is much more complicated. 95 00:06:00,680 --> 00:06:03,800 It's a mixture of different components. 96 00:06:03,800 --> 00:06:08,440 To show exactly what the air is made up of, again I need a volunteer. 97 00:06:08,440 --> 00:06:10,520 There's a hand very quickly. I saw your hand. 98 00:06:10,520 --> 00:06:12,840 Would you like to come down, please? Thank you. 99 00:06:12,840 --> 00:06:14,760 Can we have a round of applause, please? 100 00:06:16,680 --> 00:06:20,480 OK, your hand shot up very quickly there. What's your name? Nadia. 101 00:06:20,480 --> 00:06:24,120 Nadia. OK, excellent. Now, have you made air before? 102 00:06:24,120 --> 00:06:26,160 Oh, having to think about that one. 103 00:06:26,160 --> 00:06:29,920 Have you made air before, mixed it up? No. Exactly. 104 00:06:29,920 --> 00:06:32,560 Of course, the alchemist would never have done this, either. 105 00:06:32,560 --> 00:06:35,640 They didn't know what was in the air. Do you know what's in the air? 106 00:06:35,640 --> 00:06:39,560 No. No. No? Oh, come on, have a guess. Do you know any of the gases? 107 00:06:39,560 --> 00:06:42,800 Oxygen. Very good, you see, oxygen. Do you know any other ones? 108 00:06:42,800 --> 00:06:45,240 Carbon dioxide. Carbon dioxide, exactly. 109 00:06:45,240 --> 00:06:47,880 So we're going to see how many of the different gases are in air. 110 00:06:47,880 --> 00:06:49,480 Would you like to come over here? 111 00:06:49,480 --> 00:06:51,520 So these are some gas cylinders, 112 00:06:51,520 --> 00:06:53,960 and we've got the different proportions of the air 113 00:06:53,960 --> 00:06:56,640 you're going to add to this cylinder of water here. 114 00:06:56,640 --> 00:06:59,040 OK. Now, the first one is the most common gas. 115 00:06:59,040 --> 00:07:01,920 It's not oxygen, and it's not carbon dioxide. Does anybody else know? 116 00:07:01,920 --> 00:07:04,520 Do you want to shout it out? Nitrogen. 117 00:07:04,520 --> 00:07:07,320 Nitrogen. Yes, exactly. So the most common gas is nitrogen, 118 00:07:07,320 --> 00:07:08,760 and this is what we have here, 119 00:07:08,760 --> 00:07:11,440 so I'd like you to turn the tap for me, please. This tap here. 120 00:07:11,440 --> 00:07:14,040 This is going to let some nitrogen in. 121 00:07:14,040 --> 00:07:17,960 Now, we're aiming to get to this mark here. 122 00:07:17,960 --> 00:07:23,440 This is 78%. If we get up to here, it's 100%. That'd be 78% nitrogen. 123 00:07:23,440 --> 00:07:26,280 So, there's a lot of nitrogen in the air, isn't there? 124 00:07:26,280 --> 00:07:28,680 There's all this. Look at this. You've got to stop it. 125 00:07:28,680 --> 00:07:31,800 You've got to get this red mark here on the black mark, 126 00:07:31,800 --> 00:07:33,560 so you've got to get this just right. 127 00:07:33,560 --> 00:07:37,680 This is our nitrogen, and this is going to be 78%. 128 00:07:39,000 --> 00:07:44,720 Oh, stop, stop, stop, stop, stop, stop, stop! You've gone past. Sorry! 129 00:07:44,720 --> 00:07:48,120 Oh, dear, what a disaster. That's OK. Look, there we are. 130 00:07:48,120 --> 00:07:50,640 There we are. Spot on. 131 00:07:50,640 --> 00:07:54,000 78%. Well done, that's fantastic. Excellent. OK. 132 00:07:54,000 --> 00:07:57,000 Now then, the next ingredient, what's the next ingredient? 133 00:07:57,000 --> 00:08:01,280 Nitrogen? Oh, sorry. We've done nitrogen. What's the next one? 134 00:08:01,280 --> 00:08:04,640 Carbon dioxide. No. You like your carbon dioxide. Oxygen. It's oxygen. 135 00:08:04,640 --> 00:08:07,080 You're absolutely right. Very important one. 136 00:08:07,080 --> 00:08:11,160 Right. So this is our oxygen. OK? You're absolutely right there. 137 00:08:11,160 --> 00:08:13,520 You ready to go again? Yeah. Not yet, not yet. 138 00:08:13,520 --> 00:08:15,840 We've got to go to 21%. 139 00:08:15,840 --> 00:08:20,360 Now, 21%, that takes us to about here, 140 00:08:20,360 --> 00:08:25,360 I think. OK, that's 21-ish. Yes. So you're aiming for here, OK? 141 00:08:25,360 --> 00:08:27,200 Go on, then. 142 00:08:27,200 --> 00:08:29,640 That's it. Very good. 143 00:08:31,480 --> 00:08:34,160 So there's quite a lot of oxygen as well. 144 00:08:34,160 --> 00:08:37,960 I can see the concentration now. That's what we need. Very good. 145 00:08:37,960 --> 00:08:42,240 Oh, look at that. Just about spot on again. 146 00:08:42,240 --> 00:08:45,200 Remarkable. OK. Very good. 147 00:08:45,200 --> 00:08:49,360 Now, then. Now, we're coming to the third most abundant gas. 148 00:08:49,360 --> 00:08:55,040 So far, we've got 78% nitrogen, we've got 21% oxygen. 149 00:08:55,040 --> 00:09:00,760 We've almost run out of everything else. That's only 1% left. 150 00:09:00,760 --> 00:09:03,600 Does anyone know the third most abundant gas? 151 00:09:03,600 --> 00:09:06,520 You haven't mentioned this one yet. Does anybody know? Shout it out. 152 00:09:06,520 --> 00:09:08,040 SHOUTING 153 00:09:08,040 --> 00:09:12,000 All sorts of different replies there, but it is, in fact, argon. 154 00:09:12,000 --> 00:09:14,720 I think some people said argon. Pat yourself on the back there. 155 00:09:14,720 --> 00:09:16,040 It is argon. Right. 156 00:09:16,040 --> 00:09:18,400 This is a tricky one now, but you're getting very good. 157 00:09:18,400 --> 00:09:22,560 All right. Argon. This is just 1%, so that's about there. 158 00:09:22,560 --> 00:09:24,920 Can you see that? Yeah. About here, here it is, OK? 159 00:09:24,920 --> 00:09:28,960 OK. Go on, then. Go on. 160 00:09:28,960 --> 00:09:32,400 Oh, wrong one. The audience are watching. The argon one. 161 00:09:32,400 --> 00:09:35,160 That's it. Give it a go. 162 00:09:35,160 --> 00:09:36,680 Brilliant. 163 00:09:36,680 --> 00:09:40,320 There we are. Look at that. That is very good indeed. Now, then. 164 00:09:40,320 --> 00:09:41,200 APPLAUSE 165 00:09:43,960 --> 00:09:47,400 We're coming to your favourite gas. Which one's that? Carbon dioxide. 166 00:09:47,400 --> 00:09:50,200 Carbon dioxide, exactly. But there's not a lot of carbon dioxide. 167 00:09:50,200 --> 00:09:54,920 In fact, it's 0.037% carbon dioxide. 168 00:09:54,920 --> 00:09:57,800 Unless we did this 200 years ago, it would've been quite a bit less. 169 00:09:57,800 --> 00:09:59,720 We've increased the amount, but anyway... 170 00:09:59,720 --> 00:10:03,680 So carbon dioxide, we just need a quick burst from that, so quick burst. That's it. That'll do. 171 00:10:03,680 --> 00:10:05,280 That's your carbon dioxide. 172 00:10:05,280 --> 00:10:08,520 Hardly any at all, but nonetheless, very important. 173 00:10:08,520 --> 00:10:11,720 All the plants need that. So that's our carbon dioxide. 174 00:10:11,720 --> 00:10:13,800 You still haven't made perfect air yet. 175 00:10:13,800 --> 00:10:16,880 We could breathe this, that would be OK, but there are some other gases, 176 00:10:16,880 --> 00:10:18,640 and these are some rather rare gases 177 00:10:18,640 --> 00:10:21,480 but we've put all of these in this little syringe here. 178 00:10:21,480 --> 00:10:24,760 Would you like to just add your last bit of gas, 179 00:10:24,760 --> 00:10:28,120 so just push the plunger down and watch for the bubble. 180 00:10:28,120 --> 00:10:30,280 That it is, there we are. 181 00:10:30,280 --> 00:10:32,960 There, excellent. That's the last gases. 182 00:10:32,960 --> 00:10:36,160 This is neon, helium, krypton, and xenon. 183 00:10:36,160 --> 00:10:39,040 They make up just a tiny proportion of the gas. 184 00:10:39,040 --> 00:10:40,600 You did very well there. 185 00:10:40,600 --> 00:10:43,160 Thank you very much. Give her a big round of applause. 186 00:10:43,160 --> 00:10:48,920 APPLAUSE 187 00:10:49,960 --> 00:10:55,080 OK, so now then we know that air isn't just one element, 188 00:10:55,080 --> 00:10:56,640 but a mixture of many. 189 00:10:56,640 --> 00:11:00,960 Before we look at these different elements from air in more detail, 190 00:11:00,960 --> 00:11:03,760 we want to see all of the elements that occur in nature. 191 00:11:03,760 --> 00:11:05,240 Now this is where you come in. 192 00:11:05,240 --> 00:11:07,800 You've got your cards here for different elements 193 00:11:07,800 --> 00:11:10,320 so, if you're a member of the periodic table, get ready, 194 00:11:10,320 --> 00:11:12,800 but to help us with this, would you please welcome, 195 00:11:12,800 --> 00:11:17,400 straight from the West End, the cast of the musical Loserville? 196 00:11:17,400 --> 00:11:23,520 APPLAUSE 197 00:11:27,360 --> 00:11:30,400 # There's antimony, arsenic, aluminium, selenium 198 00:11:30,400 --> 00:11:32,640 # And hydrogen and oxygen and nitrogen and rhenium 199 00:11:32,640 --> 00:11:34,880 # And nickel, neodymium, neptunium, germanium 200 00:11:34,880 --> 00:11:36,720 # Iron, americium, ruthenium, uranium 201 00:11:36,720 --> 00:11:38,840 # Europium, zirconium, lutetium, vanadium 202 00:11:38,840 --> 00:11:41,000 # And lanthanum and osmium and astatine and radium 203 00:11:41,000 --> 00:11:44,440 # And gold and protactinium and indium and gallium 204 00:11:44,440 --> 00:11:48,200 # And iodine and thorium and thulium and thallium 205 00:11:48,200 --> 00:11:51,120 # There's yttrium, ytterbium, actinium, rubidium 206 00:11:51,120 --> 00:11:53,200 # And boron, gadolinium, niobium, iridium 207 00:11:53,200 --> 00:11:55,400 # And strontium and silicon and silver and samarium 208 00:11:55,400 --> 00:11:58,040 # And bismuth, bromine, lithium, beryllium, and barium... # 209 00:11:58,040 --> 00:11:59,520 Barium - very good! 210 00:12:03,320 --> 00:12:05,920 # There's holmium and helium and hafnium and erbium 211 00:12:05,920 --> 00:12:08,200 # And phosphorus and francium and fluorine and terbium 212 00:12:08,200 --> 00:12:10,440 # And manganese and mercury, molybdenum, magnesium 213 00:12:10,440 --> 00:12:12,640 # Dysprosium and scandium and cerium and cesium 214 00:12:12,640 --> 00:12:14,920 # And lead, praseodymium and platinum, plutonium 215 00:12:14,920 --> 00:12:16,960 # Palladium, promethium, potassium, polonium 216 00:12:16,960 --> 00:12:20,400 # And tantalum, technetium, titanium, tellurium, 217 00:12:20,400 --> 00:12:22,720 # And cadmium and calcium and chromium and curium 218 00:12:24,280 --> 00:12:26,720 # There's sulphur, californium and fermium, berkelium 219 00:12:26,720 --> 00:12:28,840 # And also mendelevium, einsteinium, nobelium 220 00:12:28,840 --> 00:12:31,360 # And argon, krypton, neon, radon, xenon, zinc and rhodium 221 00:12:31,360 --> 00:12:34,280 # And chlorine, carbon, cobalt, copper, tungsten, tin and sodium 222 00:12:36,440 --> 00:12:41,120 # These were the only ones they found back when this song was written 223 00:12:42,320 --> 00:12:46,640 # There are another 60 - now we'll show you where they're sitting... # 224 00:12:46,640 --> 00:12:49,000 Stand up, as well? Excellent! 225 00:12:49,000 --> 00:12:52,840 APPLAUSE 226 00:12:54,320 --> 00:12:58,560 You did very well. My whole periodic table should be standing now 227 00:12:58,560 --> 00:13:01,600 but would you please give a round of applause for the cast of Loserville? 228 00:13:01,600 --> 00:13:06,080 Thank you very much. APPLAUSE 229 00:13:06,080 --> 00:13:08,960 OK, well, that was certainly chaotic 230 00:13:08,960 --> 00:13:10,680 but you did fantastically well there. 231 00:13:10,680 --> 00:13:13,400 If you'd like to take your seats. 232 00:13:13,400 --> 00:13:15,640 Now, what about this sort of random order? 233 00:13:15,640 --> 00:13:19,080 You were springing up all over the place. Was it really a random order? 234 00:13:19,080 --> 00:13:21,160 Well, actually, it's not. 235 00:13:21,160 --> 00:13:24,240 There is some logic behind this, but to understand the logic 236 00:13:24,240 --> 00:13:27,560 we need to look right into the heart of the atom. 237 00:13:27,560 --> 00:13:31,080 So atoms, as far as the chemists are concerned at least, 238 00:13:31,080 --> 00:13:33,520 are made up of three different particles. 239 00:13:33,520 --> 00:13:37,200 In the heart of the nucleus, there are positively charged protons 240 00:13:37,200 --> 00:13:41,600 and neutral neutrons. We can see these on the screen. 241 00:13:41,600 --> 00:13:44,520 So the red ones are the protons, the blue ones are the neutrons. 242 00:13:44,520 --> 00:13:47,720 But then circling around, we have these electrons. 243 00:13:47,720 --> 00:13:51,080 It's the protons and the neutrons that give an element its mass, 244 00:13:51,080 --> 00:13:53,960 make it quite heavy, so if you pick something up and say it's heavy, 245 00:13:53,960 --> 00:13:56,240 well, that's because of the protons and neutrons. 246 00:13:56,240 --> 00:13:59,360 But it's these electrons that are right around the outside, 247 00:13:59,360 --> 00:14:02,600 and whenever you touch anything, what you're touching there is electrons. 248 00:14:02,600 --> 00:14:06,600 I bet you've never thought of this before, but if we shake hands we're shaking electrons there. 249 00:14:06,600 --> 00:14:10,480 OK, that's our electrons touching each other there. Anyway, right! 250 00:14:10,480 --> 00:14:12,000 So, here we have our atom. 251 00:14:12,000 --> 00:14:14,280 We now understand what atoms are made of 252 00:14:14,280 --> 00:14:16,680 but what's that got to do with the periodic table? 253 00:14:16,680 --> 00:14:21,680 Well, what makes an element unique is the number of protons in the atom. 254 00:14:21,680 --> 00:14:23,360 We don't really care about the neutrons 255 00:14:23,360 --> 00:14:25,080 and if it's a neutral atom, 256 00:14:25,080 --> 00:14:28,160 of course the number of protons are balanced by the number of electrons. 257 00:14:28,160 --> 00:14:31,600 Hydrogen, where are you? If you'd like to stand up, hydrogen. 258 00:14:31,600 --> 00:14:33,440 You are the first element, 259 00:14:33,440 --> 00:14:36,680 in fact the most abundant element in the universe. 260 00:14:36,680 --> 00:14:40,000 You've got one proton. That's what makes you hydrogen. 261 00:14:40,000 --> 00:14:44,240 One proton and one electron for the neutral atom. Sometimes neutrons but we don't care about those. 262 00:14:44,240 --> 00:14:47,440 The next element, on the same row, we go all the way round to here 263 00:14:47,440 --> 00:14:52,160 and we find helium. You have two protons - that's what makes you you. 264 00:14:52,160 --> 00:14:56,760 Then we come back over here to the periodic table. You're very good. 265 00:14:56,760 --> 00:14:59,960 Lithium, you've got three protons and that's what makes you you, and so on. 266 00:14:59,960 --> 00:15:02,600 That's what we do when we go from one element to the next. 267 00:15:02,600 --> 00:15:05,520 We increase the number of protons by one and the number of electrons 268 00:15:05,520 --> 00:15:08,240 in the neutral atom, and maybe throw in a few neutrons. 269 00:15:08,240 --> 00:15:12,200 Now, the question is, though, we've got 118 elements 270 00:15:12,200 --> 00:15:17,080 but we've got literally tens of millions of different compounds 271 00:15:17,080 --> 00:15:23,160 so how can we get such complexity out of just these 118 elements? 272 00:15:23,160 --> 00:15:26,280 In fact, in this cup of coffee alone, 273 00:15:26,280 --> 00:15:30,320 over 2,000 different compounds have been detected so far - 274 00:15:30,320 --> 00:15:35,080 so loads of compounds, only 118 elements. 275 00:15:35,080 --> 00:15:40,680 There's a nice analogy between letters and words with these elements and their compounds 276 00:15:40,680 --> 00:15:44,400 so I could be saying hundreds of thousands of different words now 277 00:15:44,400 --> 00:15:48,400 but these are all made up of the same 26 letters of the alphabet. 278 00:15:48,400 --> 00:15:53,240 Words like "I" and "a" are made up with a single letter. 279 00:15:53,240 --> 00:15:55,720 There are some words that have two of the same letter. 280 00:15:55,720 --> 00:15:59,040 Aa is a type of Hawaiian lava. 281 00:15:59,040 --> 00:16:02,400 What a silly word that is. But then there's another Hawaiian word. 282 00:16:02,400 --> 00:16:04,880 This is aaa, or something like that, 283 00:16:04,880 --> 00:16:08,320 which is an insect also found in Hawaii. 284 00:16:09,760 --> 00:16:11,720 Our elements have the same sort of thing. 285 00:16:11,720 --> 00:16:14,000 The letters then correspond to the elements, 286 00:16:14,000 --> 00:16:18,640 and there are some elements that just stay by themselves, like these letters. 287 00:16:18,640 --> 00:16:22,920 Helium, can you put your card up, please? Where are you? There you are. And neon, and argon. 288 00:16:22,920 --> 00:16:25,280 All of you, you just stay by yourselves, 289 00:16:25,280 --> 00:16:27,720 just single letters if you like. Single elements. 290 00:16:27,720 --> 00:16:31,840 Then we have other elements that go around in pairs. Where's nitrogen? Put your card up. 291 00:16:31,840 --> 00:16:34,400 Oxygen, fluorine, all of you go around in pairs. 292 00:16:34,400 --> 00:16:38,000 Chlorine, you go around in pairs as well, so you go around in pairs 293 00:16:38,000 --> 00:16:41,840 and occasionally oxygen - just stand up again, oxygen - occasionally 294 00:16:41,840 --> 00:16:45,240 you have three oxygen atoms that make up a molecule of ozone. 295 00:16:45,240 --> 00:16:47,080 OK, thank you very much, elements. 296 00:16:47,080 --> 00:16:48,760 But most of the periodic table, 297 00:16:48,760 --> 00:16:53,640 you are loads of these single atoms together, joined together to form 298 00:16:53,640 --> 00:16:57,920 big masses of metal or non-metals, or whatever you are, if you're solid. 299 00:16:57,920 --> 00:17:00,920 So this would be like a word like "aaaaa" going on for ever, 300 00:17:00,920 --> 00:17:03,280 with so many letters we couldn't count them. 301 00:17:03,280 --> 00:17:05,360 That's not how we usually find the elements. 302 00:17:05,360 --> 00:17:06,640 How we usually find them 303 00:17:06,640 --> 00:17:10,480 is combined with one another to form compounds 304 00:17:10,480 --> 00:17:14,040 so if the letters correspond to our elements, 305 00:17:14,040 --> 00:17:15,960 the words that we use, 306 00:17:15,960 --> 00:17:20,400 these correspond to different combinations of the elements - these are the compounds. 307 00:17:20,400 --> 00:17:25,440 So, the elements want to combine with one another to form different 308 00:17:25,440 --> 00:17:28,360 molecules and we are going to try an experiment now to show this, 309 00:17:28,360 --> 00:17:31,160 to show the combination of two elements 310 00:17:31,160 --> 00:17:34,120 and this is the element oxygen, one of the elements from the air. 311 00:17:34,120 --> 00:17:35,280 Oxygen, where are you again? 312 00:17:35,280 --> 00:17:38,280 There's oxygen. And between phosphorus. Phosphorus. 313 00:17:38,280 --> 00:17:40,320 Can you please stand up, phosphorus. 314 00:17:40,320 --> 00:17:45,760 OK, now, do you know how you were first discovered, phosphorus? No. 315 00:17:45,760 --> 00:17:48,760 OK, well, we'll give you a bit of a clue. What's your symbol? 316 00:17:48,760 --> 00:17:50,080 P. 317 00:17:50,080 --> 00:17:54,400 P. Any idea? No? Does anyone else know? 318 00:17:54,400 --> 00:17:56,360 OK, there's a chap right at the back there. 319 00:17:56,360 --> 00:18:00,000 So where do you think phosphorus was first discovered? From wee. 320 00:18:00,000 --> 00:18:01,840 From wee, yes, exactly. 321 00:18:01,840 --> 00:18:04,680 OK, so thank you, phosphorus. You can take a seat now. 322 00:18:04,680 --> 00:18:09,040 I've got some urine here - it's only mine so it's not too bad. 323 00:18:09,040 --> 00:18:10,920 AUDIENCE: Eurgh! 324 00:18:10,920 --> 00:18:13,560 It's all right! Smells quite nice. 325 00:18:13,560 --> 00:18:15,640 Do you want a sniff? Oh, you do! OK! 326 00:18:15,640 --> 00:18:18,800 LAUGHTER 327 00:18:18,800 --> 00:18:21,920 It's fine! 328 00:18:21,920 --> 00:18:23,960 Don't worry - it's only apple juice, really! 329 00:18:23,960 --> 00:18:26,200 But...OK, 330 00:18:26,200 --> 00:18:29,760 but back in 1669, 331 00:18:29,760 --> 00:18:34,680 the German alchemist Hennig Brand did take his own urine 332 00:18:34,680 --> 00:18:38,800 and he heated this up and this amazing substance came out. 333 00:18:38,800 --> 00:18:42,680 This was phosphorus. How come phosphorus was discovered so early? 334 00:18:42,680 --> 00:18:44,840 Not just because it was disgusting, 335 00:18:44,840 --> 00:18:47,560 but also because once you found it you couldn't miss it. 336 00:18:47,560 --> 00:18:51,120 It just screams out to you, "Here I am!" 337 00:18:51,120 --> 00:18:52,640 OK, let's try this. 338 00:18:52,640 --> 00:18:54,680 We've got some phosphorus in this flask here 339 00:18:54,680 --> 00:18:56,760 and I'm just going to let the air into this. 340 00:18:56,760 --> 00:18:59,920 We've removed the air and heated up the phosphorus, 341 00:18:59,920 --> 00:19:01,560 and watch what happens here. 342 00:19:01,560 --> 00:19:04,400 Maybe we can have the lights down just a little bit here. 343 00:19:06,440 --> 00:19:11,880 So, as soon as the air comes in, it combines with the phosphorus. 344 00:19:15,960 --> 00:19:20,120 This is phosphorus reacting with air, 345 00:19:20,120 --> 00:19:23,720 and this amazed the alchemists. 346 00:19:23,720 --> 00:19:26,560 When they saw this, they were truly stunned. 347 00:19:26,560 --> 00:19:30,000 In fact, they were so impressed by this amazing light 348 00:19:30,000 --> 00:19:34,240 that the reaction has given out, they named this element phosphorus, 349 00:19:34,240 --> 00:19:37,960 which means "the light giver". 350 00:19:37,960 --> 00:19:45,720 This discovery was commemorated with a painting by Joseph Wright of Derby, that's on the screen here. 351 00:19:45,720 --> 00:19:48,040 It has a really catchy title. 352 00:19:48,040 --> 00:19:51,960 It's called "the alchemist in search of the philosopher's stone 353 00:19:51,960 --> 00:19:55,640 "discovers phosphorus and prays for the successful conclusion 354 00:19:55,640 --> 00:20:01,680 "of his operation, as was the custom of the ancient chemical astrologers". 355 00:20:01,680 --> 00:20:05,240 Snappy, but it sort of says what it is, and you can see this, 356 00:20:05,240 --> 00:20:10,200 this amazing look in the alchemist's eyes as he's made this fantastic discovery. 357 00:20:10,200 --> 00:20:13,760 This was far brighter than any of their lamps or candles at the time. 358 00:20:13,760 --> 00:20:18,520 I have a description here. This is from a book from 1692. 359 00:20:18,520 --> 00:20:19,800 It describes phosphorus. 360 00:20:19,800 --> 00:20:22,800 It says you need to store it underwater because it reacts with the air, 361 00:20:22,800 --> 00:20:24,240 but it also says here, 362 00:20:24,240 --> 00:20:30,720 "If the Privy Parts be therewith rubb'd, they will be inflamed and burning a good while after." 363 00:20:32,160 --> 00:20:36,120 Now there's one that you really shouldn't try at home! 364 00:20:36,120 --> 00:20:42,120 Please don't go smearing phosphorus on your privy parts. It's not fun. 365 00:20:42,120 --> 00:20:47,400 Anyway, but the alchemists made this discovery. They found phosphorus. 366 00:20:47,400 --> 00:20:49,960 They knew it was reacting with the air 367 00:20:49,960 --> 00:20:52,280 but they didn't understand fully what was going on 368 00:20:52,280 --> 00:20:55,720 because they didn't know what the air was made of. 369 00:20:56,920 --> 00:20:59,960 Chemists now know that it's a mixture of gases 370 00:20:59,960 --> 00:21:02,440 and a mixture of different elements that makes up the air. 371 00:21:02,440 --> 00:21:06,680 Now, we're going to have a look again at the different gases that are in the air. 372 00:21:06,680 --> 00:21:10,120 In fact, first of all, can we have all the elements that are gases? 373 00:21:10,120 --> 00:21:12,360 So, all the gaseous atoms. Can you stand up, please? 374 00:21:12,360 --> 00:21:16,560 So, where are all the atoms that are gases? We have hydrogen over here. 375 00:21:16,560 --> 00:21:19,240 Well, it's a good job there's not too much of you in the air 376 00:21:19,240 --> 00:21:22,320 because that would make it very flammable, so if you sit down. 377 00:21:22,320 --> 00:21:24,520 It would all explode if there was too much hydrogen 378 00:21:24,520 --> 00:21:26,560 and that wouldn't be very good at all. Who else? 379 00:21:26,560 --> 00:21:29,040 Nitrogen and oxygen, we know you're the major components, 380 00:21:29,040 --> 00:21:31,080 but we've also got fluorine and chlorine. 381 00:21:31,080 --> 00:21:33,480 Fluorine and chlorine, you are incredibly reactive, 382 00:21:33,480 --> 00:21:36,800 which also makes you incredibly toxic so it's a very good thing 383 00:21:36,800 --> 00:21:40,600 that you're not in the air as well so perhaps you can sit down as well, please. 384 00:21:40,600 --> 00:21:43,640 Look where the gases that we do find in the air are. 385 00:21:43,640 --> 00:21:46,400 We've got nitrogen and oxygen, we've seen you, but then we've got 386 00:21:46,400 --> 00:21:50,160 all of you sitting here - well, standing here - with the white cards. 387 00:21:50,160 --> 00:21:54,840 You are the so-called noble gases. Why are you all sitting together? 388 00:21:54,840 --> 00:21:59,320 This is not a coincidence, it's because you all have very similar 389 00:21:59,320 --> 00:22:03,080 chemical properties and there's this amazing pattern when we arrange 390 00:22:03,080 --> 00:22:06,520 the elements in a certain way, that every so often 391 00:22:06,520 --> 00:22:10,800 elements with the same chemical properties are found grouped together. 392 00:22:10,800 --> 00:22:13,720 So if we just have our periodic tables up, please. 393 00:22:13,720 --> 00:22:16,080 That's it, fantastic, very good. 394 00:22:16,080 --> 00:22:18,400 We can see these coloured patterns here. 395 00:22:18,400 --> 00:22:20,840 What a beautiful display this is. Excellent. 396 00:22:20,840 --> 00:22:23,440 All of you with the purple cards here, you are group one. 397 00:22:23,440 --> 00:22:27,400 You're all really reactive metals, you explode with water. 398 00:22:27,400 --> 00:22:29,400 Really violently, OK? 399 00:22:29,400 --> 00:22:32,400 You all have similar properties, you're all grouped together. 400 00:22:32,400 --> 00:22:35,040 If we come over here, all you with the green cards for instance, 401 00:22:35,040 --> 00:22:36,680 you're called the halogens. 402 00:22:36,680 --> 00:22:39,520 You're really poisonous, rather unpleasant substances, 403 00:22:39,520 --> 00:22:42,120 but you combine with these over here with the alkali metals, 404 00:22:42,120 --> 00:22:45,400 and you form salts very violently indeed. 405 00:22:45,400 --> 00:22:47,520 OK, at ease, periodic table. 406 00:22:47,520 --> 00:22:51,120 We're going to look, though, at our noble gases. 407 00:22:51,120 --> 00:22:55,800 So, if everyone sits down, but I'd like the noble gases now to come down to the front. 408 00:22:55,800 --> 00:23:01,000 We've got some samples for you. A balloon of krypton. 409 00:23:01,000 --> 00:23:03,200 Hold the string and hold it out. Beautiful. 410 00:23:03,200 --> 00:23:06,840 OK. Xenon, again, hold the string, there we are. 411 00:23:06,840 --> 00:23:11,800 And then we come... Ah! We have a slight problem with radon, I'm afraid. 412 00:23:11,800 --> 00:23:14,120 Radon is incredibly radioactive 413 00:23:14,120 --> 00:23:17,920 so health and safety wouldn't let us give you a balloon full of radon. 414 00:23:17,920 --> 00:23:22,760 You would go home glowing, so we'll just put this one on you there. 415 00:23:22,760 --> 00:23:24,000 That's great. 416 00:23:26,440 --> 00:23:30,600 And ununoctium, I'm afraid ununoctium hasn't even got a name 417 00:23:30,600 --> 00:23:35,200 and this is because there's so few atoms of ununoctium that were made, 418 00:23:35,200 --> 00:23:37,240 or we're not even sure if they were made, 419 00:23:37,240 --> 00:23:40,440 but we couldn't fill a balloon full of you. But you got a balloon anyway! 420 00:23:40,440 --> 00:23:44,920 LAUGHTER 421 00:23:44,920 --> 00:23:48,160 OK, so, mm-hmm, right. 422 00:23:48,160 --> 00:23:49,840 Now, you've all got your balloons 423 00:23:49,840 --> 00:23:53,600 and after a countdown from three, I'd like you to release your balloons. 424 00:23:53,600 --> 00:23:56,880 Keep hold of the strings, though, and we'll see what happens. 425 00:23:56,880 --> 00:23:58,080 So three, two, one, go. 426 00:23:59,560 --> 00:24:02,080 Ah! Look at that. Now, what do we see here? 427 00:24:02,080 --> 00:24:04,520 We all know that helium balloons float 428 00:24:04,520 --> 00:24:08,280 so you've got a nice light element there, helium. What about this neon? 429 00:24:08,280 --> 00:24:13,320 Neon, hmm, it's about the same. You've dropped your string. 430 00:24:13,320 --> 00:24:17,640 Keep hold of the string. It's about the same sort of density as air. 431 00:24:17,640 --> 00:24:23,120 It's the balloon that's making it sink. Argon is getting pretty, er... Whoops! More dense there. 432 00:24:23,120 --> 00:24:27,200 Keep hold, thank you. Krypton is really quite heavy. 433 00:24:27,200 --> 00:24:31,960 And xenon, hmm, you wouldn't want to go to a party with that, would you? 434 00:24:31,960 --> 00:24:34,040 You would be dragging this along the floor! 435 00:24:34,040 --> 00:24:36,920 It's a very expensive gas - it's about £100, this balloon, 436 00:24:36,920 --> 00:24:41,000 but yes, it's very heavy indeed. What does this tell us, though? 437 00:24:41,000 --> 00:24:45,720 Each of these balloons actually has the same number of atoms 438 00:24:45,720 --> 00:24:48,960 because equal volumes contain the same number of particles. 439 00:24:48,960 --> 00:24:56,360 It tells us that the atoms of helium are much lighter than the atoms of xenon 440 00:24:56,360 --> 00:24:59,640 and that's because of the subatomic particles that make up these atoms. 441 00:24:59,640 --> 00:25:03,120 The helium just has two protons and two neutrons 442 00:25:03,120 --> 00:25:07,200 all the way down to ununoctium - you have 118 protons and loads of neutrons. 443 00:25:07,200 --> 00:25:09,200 I think you've done fantastically well. 444 00:25:09,200 --> 00:25:11,600 Would you like to return to your seats? Thank you. 445 00:25:11,600 --> 00:25:14,680 APPLAUSE 446 00:25:14,680 --> 00:25:17,520 We've seen that we've got different densities of these gases, 447 00:25:17,520 --> 00:25:18,760 they have different masses, 448 00:25:18,760 --> 00:25:21,680 but they also have very similar properties 449 00:25:21,680 --> 00:25:24,640 and each of these elements is a gas 450 00:25:24,640 --> 00:25:28,000 and we've filled these signs up with these gases. 451 00:25:28,000 --> 00:25:29,520 We can see that you're all colourless. 452 00:25:29,520 --> 00:25:33,080 You're also all odourless gases, which is a good thing. 453 00:25:33,080 --> 00:25:36,360 You don't smell at all, but not very exciting to look at, 454 00:25:36,360 --> 00:25:40,360 until you pass a few thousand volts through you. Watch what happens then. 455 00:25:40,360 --> 00:25:43,120 They all become much prettier. 456 00:25:43,120 --> 00:25:46,800 This is the normal neon signs that we see. 457 00:25:46,800 --> 00:25:50,840 This sign here is filled with neon gas, but when it gets excited 458 00:25:50,840 --> 00:25:53,680 with the electricity there, the electrons are leaping up, 459 00:25:53,680 --> 00:25:57,560 and as they come back down we get this fantastic red colour. 460 00:25:57,560 --> 00:26:00,200 Each element has its own unique colour 461 00:26:00,200 --> 00:26:03,360 so we can see, then, that some of these gases have uses. 462 00:26:03,360 --> 00:26:05,480 Neon is used in neon signs. 463 00:26:05,480 --> 00:26:11,200 But some of them have even more important uses, and I went to the 464 00:26:11,200 --> 00:26:15,440 University of Sheffield to have a look at one of the uses for helium. 465 00:26:17,280 --> 00:26:20,960 So what's in this little bag here that I've got then, Jim? 466 00:26:20,960 --> 00:26:25,440 What you've got in there is essentially a bag with some helium atoms, 467 00:26:25,440 --> 00:26:29,240 which are magnetically aligned or polarised. 468 00:26:29,240 --> 00:26:31,680 They are contained within the bag. 469 00:26:31,680 --> 00:26:33,680 If we were to actually image the bag, you'd see 470 00:26:33,680 --> 00:26:37,240 just the boundaries of the bag and the air space inside the bag 471 00:26:37,240 --> 00:26:40,840 filled with the gas and nothing on the outside and, similarly, 472 00:26:40,840 --> 00:26:44,480 when you breathe it in we will see the gas inside your lungs. 473 00:26:44,480 --> 00:26:48,160 The scanner is actually a giant magnet with radio detectors 474 00:26:48,160 --> 00:26:52,480 which detect the specially prepared helium atoms as they return 475 00:26:52,480 --> 00:26:54,760 to their natural state within this magnet. 476 00:26:54,760 --> 00:26:59,760 This allows Jim to build up a picture of where the gases are in my lungs. 477 00:26:59,760 --> 00:27:02,560 Your scan is here. Those are my lungs? 478 00:27:04,000 --> 00:27:07,560 There's your bronchus, trachea, and your two bronchi, 479 00:27:07,560 --> 00:27:09,440 main feeding bronchi coming off the bronchus. 480 00:27:09,440 --> 00:27:10,840 These are your blood vessels. 481 00:27:10,840 --> 00:27:14,960 So the amazing thing about this is that we are only seeing 482 00:27:14,960 --> 00:27:18,160 the air inside my lungs, aren't we? Exactly. 483 00:27:18,160 --> 00:27:21,240 You're just visualising the air spaces there. 484 00:27:21,240 --> 00:27:24,680 It's very exciting to be looking at my own lungs! 485 00:27:24,680 --> 00:27:26,960 It's nice to know they're not too bad, even though 486 00:27:26,960 --> 00:27:29,680 I know I've got a bit of a cough at the moment. 487 00:27:29,680 --> 00:27:34,320 Nonetheless, they're reasonably healthy, you think? They look pretty healthy. That's all right, then. 488 00:27:34,320 --> 00:27:36,360 So this is pretty cutting-edge science here. 489 00:27:36,360 --> 00:27:40,120 We're actually using this form of helium, helium three, 490 00:27:40,120 --> 00:27:43,680 to image the workings, how our lung works. 491 00:27:43,680 --> 00:27:47,040 And actually on the screen we can see here, these are two lungs. 492 00:27:47,040 --> 00:27:51,280 This is a lung of a patient who has asthma on the left-hand side here. 493 00:27:51,280 --> 00:27:52,920 You can see some black regions. 494 00:27:52,920 --> 00:27:57,600 But after they've taken their inhaler, the lungs have opened up, 495 00:27:57,600 --> 00:28:01,040 the airways have opened up, and the helium has gone into those regions. 496 00:28:01,040 --> 00:28:04,480 We can see all the places where the air is now reaching. 497 00:28:04,480 --> 00:28:07,560 So this just shows the medicine in action. 498 00:28:07,560 --> 00:28:12,520 OK, now, it's not just helium that has exciting properties. 499 00:28:12,520 --> 00:28:15,760 If we go right the way down to the bottom of the periodic table here, 500 00:28:15,760 --> 00:28:18,000 the heavy stable element xenon, 501 00:28:18,000 --> 00:28:20,840 this has some truly remarkable properties as well. 502 00:28:20,840 --> 00:28:25,360 We have a tank here and we've filled this with some xenon, I understand. A little, yes. 503 00:28:25,360 --> 00:28:28,800 A little xenon so we just keep putting a little bit more in there 504 00:28:28,800 --> 00:28:35,160 and I have a very delicate, very fragile foil boat. 505 00:28:37,240 --> 00:28:40,440 I'm going to see if we can actually balance this, 506 00:28:40,440 --> 00:28:44,800 if we can float this on the xenon in this tank. 507 00:28:44,800 --> 00:28:47,560 Try this one. Shall we try this one first? 508 00:28:47,560 --> 00:28:51,000 Yes, we'll try our new boat. Just slide this over. 509 00:28:56,600 --> 00:29:00,040 And try our new boat. 510 00:29:00,040 --> 00:29:03,040 Ah! That's it. Look at that. 511 00:29:03,040 --> 00:29:06,440 That really is... APPLAUSE 512 00:29:06,440 --> 00:29:09,280 ..floating on the xenon. 513 00:29:11,440 --> 00:29:15,160 There are no strings. It's a little bit fragile here. 514 00:29:15,160 --> 00:29:18,640 I think I need a volunteer to just come and very carefully help me 515 00:29:18,640 --> 00:29:21,280 add some weight into this. 516 00:29:21,280 --> 00:29:26,160 We'll have somebody from, er, the... Yes, right on the end. 517 00:29:26,160 --> 00:29:29,000 Would you like to come down? Thank you. 518 00:29:31,640 --> 00:29:34,400 OK, thank you very much. Give her a round of applause. 519 00:29:34,400 --> 00:29:37,520 If you'd like to come round here. 520 00:29:37,520 --> 00:29:40,640 I'm just trying to keep my boat level here. 521 00:29:40,640 --> 00:29:43,800 Just add a little bit more xenon. What's your name, please? Bethany. 522 00:29:43,800 --> 00:29:45,600 Bethany, excellent. 523 00:29:45,600 --> 00:29:48,480 Now, you are going to be probably the first person in the world 524 00:29:48,480 --> 00:29:50,920 ever to try this - we haven't even practised this. 525 00:29:50,920 --> 00:29:55,400 Have a look at this. What do you think this is? Hold it. 526 00:29:55,400 --> 00:29:59,080 Foil. It's foil. Does it feel like normal foil? No. 527 00:29:59,080 --> 00:30:02,920 No, it feels strange, doesn't it? That's because it's pure solid gold. 528 00:30:02,920 --> 00:30:04,520 Right? 529 00:30:04,520 --> 00:30:07,000 This is pure solid gold so let's just screw it up a little bit 530 00:30:07,000 --> 00:30:09,000 and I'd like you to put this in here. 531 00:30:09,000 --> 00:30:10,680 Just see if you can put it in that corner. 532 00:30:10,680 --> 00:30:14,320 That corner is a little bit unstable at the moment. That's it. Oh, look at that! 533 00:30:14,320 --> 00:30:17,320 Now you have made this thing float perfectly. That's pretty amazing. 534 00:30:17,320 --> 00:30:19,760 Add some more. Will you sink it? 535 00:30:21,120 --> 00:30:22,640 Not quite. Oh, there it goes. 536 00:30:22,640 --> 00:30:25,240 Fantastic! A world first. 537 00:30:25,240 --> 00:30:27,360 Thank you very much, excellent. 538 00:30:27,360 --> 00:30:31,760 APPLAUSE 539 00:30:31,760 --> 00:30:37,520 OK, xenon is very dense and I'm very pleased that worked, but it also has 540 00:30:37,520 --> 00:30:41,960 some really remarkable properties that can be used in medicine. 541 00:30:41,960 --> 00:30:45,160 Now, while I was at the University of Sheffield, 542 00:30:45,160 --> 00:30:48,840 we took a chance to experience what it's like to breathe in 543 00:30:48,840 --> 00:30:52,080 some xenon and it has very strange effects on the body 544 00:30:52,080 --> 00:30:56,600 but it can be very useful as well, so let's just see what happens here. 545 00:30:56,600 --> 00:31:00,800 If you take a deep breath in, Peter. Breathe out. 546 00:31:00,800 --> 00:31:02,240 Deep breath in. 547 00:31:04,680 --> 00:31:08,400 Breathe out, and now breathe from the bag. OK. 548 00:31:08,400 --> 00:31:11,600 Breathe in, breathe in, breathe in, breathe in, breathe in, breathe in, 549 00:31:11,600 --> 00:31:16,240 breathe in, breathe in, breathe in, breathe in, breathe in, breathe in. 550 00:31:16,240 --> 00:31:18,240 OK, and hold your breath. 551 00:31:21,360 --> 00:31:23,560 It will be interesting if you talk as you breathe out, 552 00:31:23,560 --> 00:31:25,800 we'll see if we can hear the, er... 553 00:31:28,040 --> 00:31:30,560 DEEP VOICE: That's amazing. I feel really relaxed 554 00:31:30,560 --> 00:31:33,720 and I can hear that my voice has changed. 555 00:31:33,720 --> 00:31:38,600 It's gone quite deep now but I feel very happy and relaxed 556 00:31:38,600 --> 00:31:40,600 and calm. Oh, it's wearing off now. 557 00:31:40,600 --> 00:31:45,920 Wow, so that's xenon, these individual atoms of xenon, 558 00:31:45,920 --> 00:31:48,960 interacting with my brain in some way, isn't it? Mmm. 559 00:31:48,960 --> 00:31:52,640 So it's going into my bloodstream and interacting with my brain 560 00:31:52,640 --> 00:31:55,480 and making me feel slightly light-headed. Mmm. And that's... 561 00:31:55,480 --> 00:31:58,520 At higher concentrations, that acts as an anaesthetic 562 00:31:58,520 --> 00:32:00,120 and I would just pass out, is that right? 563 00:32:00,120 --> 00:32:02,760 People do use it as an anaesthetic in a clinical setting, 564 00:32:02,760 --> 00:32:05,200 but clearly at higher concentrations than these. 565 00:32:05,200 --> 00:32:08,440 If we'd have retuned the scanner slightly, we'd have actually seen 566 00:32:08,440 --> 00:32:11,000 the xenon atoms dissolved in your blood as well. 567 00:32:11,000 --> 00:32:13,160 That's where we're going with this at the moment. 568 00:32:13,160 --> 00:32:15,720 We'd love to actually be able to pick up the xenon 569 00:32:15,720 --> 00:32:18,440 dissolved in the brain and image the xenon in the brain. 570 00:32:18,440 --> 00:32:20,440 That might give us some insight into how these 571 00:32:20,440 --> 00:32:23,840 anaesthetics are actually working in the neural system. 572 00:32:23,840 --> 00:32:25,800 Incredible. Yeah. 573 00:32:25,800 --> 00:32:29,880 Now, that was certainly very strange when I was breathing in this gas 574 00:32:29,880 --> 00:32:34,200 and the latest research that Jim is doing allows the individual atoms 575 00:32:34,200 --> 00:32:37,320 of xenon to be followed around the brain, even. 576 00:32:37,320 --> 00:32:41,400 Now, I'd like you to welcome three incredibly important guests 577 00:32:41,400 --> 00:32:46,400 to the RI. Would you please welcome Dave, Sarah and Riley Joyce? 578 00:32:46,400 --> 00:32:50,600 APPLAUSE 579 00:32:50,600 --> 00:32:52,720 Good to see you. 580 00:32:52,720 --> 00:32:55,080 Thank you very much. Hello. Thank you. 581 00:32:55,080 --> 00:32:58,920 Ah! He's very shy in front of the cameras here. 582 00:32:58,920 --> 00:33:01,280 I was wondering if... Could you tell me your middle name? 583 00:33:01,280 --> 00:33:04,120 What's your full name? Can you tell me your full name? 584 00:33:04,120 --> 00:33:08,160 A bit shy. He's a bit shy, but what is his full name, then, please? 585 00:33:08,160 --> 00:33:12,040 It's Riley Xenon Joyce. I think this is great. 586 00:33:12,040 --> 00:33:15,680 I would love to have an element for a middle name, I must say. 587 00:33:15,680 --> 00:33:19,120 So why is Riley's middle name Xenon, then? 588 00:33:19,120 --> 00:33:23,200 Well, Riley was the first baby in the world to receive xenon, 589 00:33:23,200 --> 00:33:27,280 and he received it at St Michael's in Bristol, 590 00:33:27,280 --> 00:33:30,720 due to when he was born he didn't have a pulse 591 00:33:30,720 --> 00:33:34,320 and they had to resuscitate him so he was starved of oxygen. 592 00:33:34,320 --> 00:33:38,720 This could have caused complications if he didn't get this treatment at the time, 593 00:33:38,720 --> 00:33:41,160 so this was acting as an anaesthetic. 594 00:33:41,160 --> 00:33:46,640 Would it just gently put him to sleep and allow the metabolism to slow down? 595 00:33:46,640 --> 00:33:50,160 It has given his brain time to recover and he had it alongside 596 00:33:50,160 --> 00:33:54,040 the head-cooling treatment, which works on the same principle. 597 00:33:54,040 --> 00:33:57,560 I must say that he's very shy at the moment in front of everybody 598 00:33:57,560 --> 00:33:59,960 but earlier he was running around all over the place 599 00:33:59,960 --> 00:34:04,160 so he's clearly perfectly healthy now, isn't he? Is that right? He is. 600 00:34:04,160 --> 00:34:07,800 In March this year he had his two-year check-up 601 00:34:07,800 --> 00:34:12,120 and he was discharged as a perfectly normal, healthy child. 602 00:34:12,120 --> 00:34:16,000 When he was born, he was given a 50% chance of having permanent brain damage 603 00:34:16,000 --> 00:34:19,880 so to come from there to where we are now is incredible. 604 00:34:19,880 --> 00:34:22,120 That is absolutely fantastic. 605 00:34:22,120 --> 00:34:25,360 So would you please thank them for coming in? 606 00:34:25,360 --> 00:34:30,640 APPLAUSE 607 00:34:33,600 --> 00:34:36,200 If we just have our periodic table up for a moment. 608 00:34:36,200 --> 00:34:38,760 Have our periodic table up. 609 00:34:38,760 --> 00:34:41,400 We've seen that we have our noble gases here. 610 00:34:41,400 --> 00:34:43,280 You're all individual atoms, 611 00:34:43,280 --> 00:34:46,240 you don't really want to combine with the others, 612 00:34:46,240 --> 00:34:49,160 but this isn't the same throughout the periodic table as a whole. 613 00:34:49,160 --> 00:34:52,200 We're trying to understand what makes some of the gases in the air so special, 614 00:34:52,200 --> 00:34:55,520 but in order to understand these, how they're bonding with each other, 615 00:34:55,520 --> 00:34:58,840 we need to look across the periodic table as a whole. 616 00:34:58,840 --> 00:35:01,520 I have a sample of one of the elements here. 617 00:35:01,520 --> 00:35:04,520 This is the element potassium. Potassium, can you stand up? 618 00:35:04,520 --> 00:35:05,800 There you are. 619 00:35:05,800 --> 00:35:09,480 So you're in this first group, the same group as lithium, sodium, potassium. Thank you. 620 00:35:09,480 --> 00:35:13,600 You're a solid, and in here we have the solid potassium. 621 00:35:14,920 --> 00:35:19,040 Potassium is a metal, and we've got this in the flask. 622 00:35:19,040 --> 00:35:22,480 At ease, periodic table. Thank you. Cards down. Very good. 623 00:35:22,480 --> 00:35:28,920 We've got a little piece of potassium here, and we've taken the air out of this flask. 624 00:35:31,400 --> 00:35:35,040 And I'm just going to gently warm the flask up. 625 00:35:37,560 --> 00:35:39,800 So potassium is a metal. 626 00:35:39,800 --> 00:35:43,440 The potassium atoms want to bond to each other 627 00:35:43,440 --> 00:35:45,800 but they don't bond to each other very tightly. 628 00:35:45,800 --> 00:35:49,760 So it is a solid, though, not a gas like our noble gases, 629 00:35:49,760 --> 00:35:53,480 but watch what happens if I just warm it up rather gently. 630 00:35:53,480 --> 00:35:57,360 Potassium is... Oh, look at that. 631 00:35:57,360 --> 00:36:01,440 What's happened here, all of the potassium atoms have separated 632 00:36:01,440 --> 00:36:05,840 from each other and given this fantastic coating over the inside. 633 00:36:05,840 --> 00:36:09,800 In fact, we've made an instant Christmas bauble, which is great! 634 00:36:09,800 --> 00:36:12,520 But this is a Christmas bauble coated with potassium, 635 00:36:12,520 --> 00:36:15,880 which is probably not so great. But anyway, very beautiful, 636 00:36:15,880 --> 00:36:19,800 but we didn't need to put a lot of energy in to pull those apart. 637 00:36:19,800 --> 00:36:22,560 How can we understand this? We're going to go back to... 638 00:36:22,560 --> 00:36:24,000 If we have the periodic table back up, 639 00:36:24,000 --> 00:36:28,040 we're going to go back to the top element in this second row. 640 00:36:28,040 --> 00:36:29,560 This is lithium, 641 00:36:29,560 --> 00:36:32,320 and we're going to move round the periodic table from lithium 642 00:36:32,320 --> 00:36:33,760 through beryllium, all the way - 643 00:36:33,760 --> 00:36:37,600 boron, carbon, nitrogen, oxygen, fluorine, neon - and see how the bonding changes. 644 00:36:37,600 --> 00:36:40,040 We have our elements lined up and bringing down electrons 645 00:36:40,040 --> 00:36:42,000 so can we have the first two lithiums, please? 646 00:36:42,000 --> 00:36:45,440 Could you come down to the front, and you're bringing some electrons with you. 647 00:36:45,440 --> 00:36:46,760 So these are our yellow electrons 648 00:36:46,760 --> 00:36:49,480 and could you put them in the energy level here, please? 649 00:36:49,480 --> 00:36:51,040 That's it, put them in there, 650 00:36:51,040 --> 00:36:53,880 and if you return to your seats, that's great. Thank you very much. 651 00:36:53,880 --> 00:36:57,200 What's happened here, as the electrons have gone into this region here, 652 00:36:57,200 --> 00:37:02,560 into these shelves here, these have pulled the atoms together 653 00:37:02,560 --> 00:37:05,800 and this is because these negatively charged electrons 654 00:37:05,800 --> 00:37:08,480 are helping pull the nuclei together 655 00:37:08,480 --> 00:37:11,080 when they're concentrated in between the two atoms here. 656 00:37:11,080 --> 00:37:12,760 Can we have our next elements? 657 00:37:12,760 --> 00:37:14,600 We have beryllium - could you come down? 658 00:37:14,600 --> 00:37:17,640 Now, on beryllium we see on the screen here the bonds are much stronger. 659 00:37:17,640 --> 00:37:20,880 Let's see why this is. We add your electron here. 660 00:37:20,880 --> 00:37:23,280 That's it, these are moving the atoms closer together, 661 00:37:23,280 --> 00:37:25,720 so even stronger still. 662 00:37:25,720 --> 00:37:29,240 So beryllium has two electrons, creates a stronger bond now. 663 00:37:29,240 --> 00:37:33,240 Lithium, beryllium. The beryllium atoms are held more tightly. 664 00:37:33,240 --> 00:37:37,240 OK, boron, on the screen here, we have three electrons. 665 00:37:37,240 --> 00:37:41,440 Can you come down please, boron? You've got one more electron here than the beryllium had 666 00:37:41,440 --> 00:37:44,840 so you're going to add your electrons. Could you add your electrons in here? 667 00:37:44,840 --> 00:37:49,080 And again, these... Oh! That really did move, that was pretty good. 668 00:37:49,080 --> 00:37:51,040 So you've a very strong bond now for the boron - 669 00:37:51,040 --> 00:37:53,360 much stronger than the beryllium. Very tightly held. 670 00:37:53,360 --> 00:37:56,600 We've got three electrons bonding these boron atoms together. 671 00:37:56,600 --> 00:38:01,280 Can we have carbons now, please? OK, and that last one. 672 00:38:01,280 --> 00:38:03,480 OK, so the atoms move closer together. 673 00:38:03,480 --> 00:38:07,600 Thank you very much, carbons. We've got some very strong bonds indeed now. 674 00:38:07,600 --> 00:38:14,480 In fact carbon there requires most of the energy of all of the elements to try and rip them apart. 675 00:38:14,480 --> 00:38:16,960 If we were trying to remove the same number of atoms apart, 676 00:38:16,960 --> 00:38:19,560 we need more energy for carbon than any other. 677 00:38:19,560 --> 00:38:22,240 This makes carbon incredibly strong. 678 00:38:22,240 --> 00:38:26,080 I have a sample of carbon here to show you and demonstrate this. 679 00:38:26,080 --> 00:38:30,360 This is a diamond, we can see this here. This is a real diamond. 680 00:38:30,360 --> 00:38:32,640 Very, very strong because of these strong bonds. 681 00:38:32,640 --> 00:38:36,640 I nearly dropped it there. But it is also incredibly hard. 682 00:38:36,640 --> 00:38:41,520 So hard, in fact, that I can actually cut this glass. 683 00:38:41,520 --> 00:38:45,960 The glass is incredibly hard, of course, but diamond is even stronger 684 00:38:45,960 --> 00:38:49,400 because of the strong bonds between the carbon atoms. So... 685 00:38:53,200 --> 00:38:57,800 It's definitely cut into the glass. In fact, it looks like it's pretty deep. 686 00:39:00,640 --> 00:39:06,320 There we are. It's cut down this crack where it's been scored with the glass there. 687 00:39:06,320 --> 00:39:10,920 So a diamond, incredibly strong, because of all these bonding electrons 688 00:39:10,920 --> 00:39:12,840 keeping the carbon atoms together. 689 00:39:12,840 --> 00:39:15,120 We've still got further to go along our periodic table. 690 00:39:15,120 --> 00:39:17,280 We've gone to carbon, we're going to keep on going. 691 00:39:17,280 --> 00:39:20,000 So nitrogens, you have five electrons in total, 692 00:39:20,000 --> 00:39:24,160 so let's see where these have to go. We've run out of room here. 693 00:39:24,160 --> 00:39:26,760 You're going to have to put your electrons in these ones 694 00:39:26,760 --> 00:39:29,040 so this is a slightly different thing going on here. 695 00:39:29,040 --> 00:39:31,680 Would you put your electrons in here? That's great. 696 00:39:31,680 --> 00:39:36,160 And these, actually, now are concentrated outside of the middle 697 00:39:36,160 --> 00:39:39,840 and these electrons are pulling the atoms further apart again. 698 00:39:39,840 --> 00:39:43,240 In fact, these do not help the bonding. These are called anti-bonding levels. 699 00:39:43,240 --> 00:39:44,880 Thank you very much, nitrogens. 700 00:39:44,880 --> 00:39:48,240 OK, we have our next element - this is oxygen. 701 00:39:48,240 --> 00:39:51,880 Let's see what happens as we keep going, adding another electron. 702 00:39:51,880 --> 00:39:54,520 Oxygens, you have to put yours in this level here, 703 00:39:54,520 --> 00:39:58,680 and again these are in these anti-bonding levels, pulling our atoms apart. 704 00:39:58,680 --> 00:40:01,720 So oxygen is a weaker bond than nitrogen. 705 00:40:01,720 --> 00:40:04,200 Let's go to our next atom. We've got two fluorines coming. 706 00:40:04,200 --> 00:40:07,040 Let's see what happens when you get together. OK. Add them in. 707 00:40:07,040 --> 00:40:11,120 That's great. Again, a very weak bond now. It's pulled further apart. 708 00:40:11,120 --> 00:40:14,360 Fluorine has one more electron, weakens the bond here 709 00:40:14,360 --> 00:40:17,400 and the fluorines are really weakly held together. 710 00:40:17,400 --> 00:40:19,480 This is the one of the reasons that makes fluorine 711 00:40:19,480 --> 00:40:22,560 so incredibly reactive. It's because of these weak bonds. 712 00:40:22,560 --> 00:40:25,640 Finally, we have our last element, neon. 713 00:40:25,640 --> 00:40:27,960 So, neon has eight outermost electrons, 714 00:40:27,960 --> 00:40:30,600 so it has one more than the fluorines had. 715 00:40:30,600 --> 00:40:33,400 Let's see where these have to go in the remaining level here. 716 00:40:33,400 --> 00:40:36,480 So if you add your electrons into these last anti-bonding levels... 717 00:40:36,480 --> 00:40:38,800 And it pulls the atoms completely apart. 718 00:40:38,800 --> 00:40:41,560 So, this means the atoms do not bond to each other. 719 00:40:41,560 --> 00:40:44,800 Thank you very much indeed for your help there. Thank you. 720 00:40:44,800 --> 00:40:47,240 APPLAUSE 721 00:40:49,360 --> 00:40:52,720 So, if we just see our periodic table again. Just have you up. 722 00:40:52,720 --> 00:40:54,760 That's great. Thank you very much. 723 00:40:54,760 --> 00:40:56,880 We're looking at these ones over here. 724 00:40:56,880 --> 00:40:59,000 We see carbon, very, very strong bonds. 725 00:40:59,000 --> 00:41:02,040 Nitrogen, not as strong as carbon, but still pretty strong. 726 00:41:02,040 --> 00:41:04,760 Fluorine, very weak bonds. Neon not bonded at all. 727 00:41:04,760 --> 00:41:07,760 But oxygen, you're just about the right strength. 728 00:41:07,760 --> 00:41:10,760 You're still reactive because the bonds aren't too incredibly strong 729 00:41:10,760 --> 00:41:12,320 between the oxygen atoms. 730 00:41:12,320 --> 00:41:14,640 Makes you very, very reactive indeed. 731 00:41:14,640 --> 00:41:17,720 Oxygen, you really are the elixir of life. 732 00:41:17,720 --> 00:41:21,480 It's you that keeps us all alive. I'm going to demonstrate this now. 733 00:41:21,480 --> 00:41:24,000 So, at ease, periodic table. Thank you. 734 00:41:24,000 --> 00:41:26,120 So, I have some breakfast cereal here. 735 00:41:26,120 --> 00:41:28,680 This is just normal breakfast cereal. 736 00:41:28,680 --> 00:41:30,280 I'm just going to put some in the bowl. 737 00:41:30,280 --> 00:41:34,240 This is just the sort of thing that you would normally do. 738 00:41:34,240 --> 00:41:37,000 But now instead of adding my milk... Oops. 739 00:41:37,000 --> 00:41:42,080 Instead of adding my milk, I'm going to add some liquid oxygen. 740 00:41:42,080 --> 00:41:44,160 So this is not the sort of thing you normally do. 741 00:41:44,160 --> 00:41:46,560 We've cooled the oxygen down. So this is oxygen gas 742 00:41:46,560 --> 00:41:49,160 that's been cooled down. It has this beautiful blue colour. 743 00:41:49,160 --> 00:41:51,960 I'm just going to pour this onto our Rice Krispies. 744 00:41:55,080 --> 00:41:59,200 OK. Now, I'm also going to add a light. 745 00:41:59,200 --> 00:42:01,680 Just put my goggles on. 746 00:42:01,680 --> 00:42:04,200 This is also something you don't normally do. 747 00:42:13,760 --> 00:42:18,920 An incredible amount of energy is released there. 748 00:42:18,920 --> 00:42:23,120 This is as the Rice Krispies, the breakfast cereal here... 749 00:42:23,120 --> 00:42:28,400 As our breakfast cereal combines with the oxygen from the air. 750 00:42:28,400 --> 00:42:31,320 And believe it or not, this is actually what happens 751 00:42:31,320 --> 00:42:34,560 inside our bodies. Not quite like this. 752 00:42:34,560 --> 00:42:37,760 We don't have flames coming out of our ears. 753 00:42:37,760 --> 00:42:41,440 But nonetheless, it is the reaction between our breakfast cereal 754 00:42:41,440 --> 00:42:44,320 and the oxygen that we're breathing in that gives us 755 00:42:44,320 --> 00:42:46,640 the energy to stay alive. 756 00:42:46,640 --> 00:42:50,640 And we have Laura here to demonstrate this. 757 00:42:50,640 --> 00:42:53,560 She's been specially trained in breathing 758 00:42:53,560 --> 00:42:56,520 with this rather delicate apparatus here. 759 00:42:56,520 --> 00:42:59,040 OK. Would you like to put this on? 760 00:42:59,040 --> 00:43:00,800 Now, what's happening here? 761 00:43:00,800 --> 00:43:03,760 Laura is breathing in. So if you breathe in... 762 00:43:03,760 --> 00:43:06,080 Breathing in normal air and it's coming in through here, 763 00:43:06,080 --> 00:43:09,200 bubbling through this solution. In the flask here, 764 00:43:09,200 --> 00:43:11,480 we have something called lime water. 765 00:43:11,480 --> 00:43:14,080 Then Laura's breathing out through this one. So the out air 766 00:43:14,080 --> 00:43:15,320 is coming out through here. 767 00:43:15,320 --> 00:43:18,920 Now, lime water reacts with carbon dioxide. 768 00:43:18,920 --> 00:43:21,680 There's very little carbon dioxide in the air, 769 00:43:21,680 --> 00:43:24,440 so there's no change taking place here. 770 00:43:24,440 --> 00:43:26,920 When lime water reacts with carbon dioxide, 771 00:43:26,920 --> 00:43:30,840 it turns cloudy due to the formation of calcium carbonate. 772 00:43:30,840 --> 00:43:33,800 No calcium carbonate forming here. But in the out... 773 00:43:33,800 --> 00:43:36,840 Well, we can begin to see already... Keep breathing. Very good. 774 00:43:36,840 --> 00:43:40,200 You're breathing beautifully there. OK. In the out, we can begin 775 00:43:40,200 --> 00:43:44,560 to see that it is going cloudy. And this is because inside Laura, 776 00:43:44,560 --> 00:43:47,600 it is the same reaction we saw taking place there. 777 00:43:47,600 --> 00:43:51,040 The breakfast cereal Laura had this morning is reacting 778 00:43:51,040 --> 00:43:53,880 with the oxygen she's breathing in. It's releasing a lot of energy 779 00:43:53,880 --> 00:43:57,360 and that's keeping her alive, but she's breathing out carbon dioxide 780 00:43:57,360 --> 00:44:00,560 that is formed during this process as the oxygen reacts 781 00:44:00,560 --> 00:44:03,440 with the fuel to produce carbon dioxide. 782 00:44:03,440 --> 00:44:05,960 Thank you very much. Give Laura a round of applause. 783 00:44:05,960 --> 00:44:08,080 APPLAUSE 784 00:44:12,320 --> 00:44:17,680 So, oxygen is incredibly important just to stay alive. 785 00:44:17,680 --> 00:44:23,040 But we've seen that there's only 21% of oxygen in the air. 786 00:44:23,040 --> 00:44:27,280 So, wouldn't it be better if there was much more oxygen in the air? 787 00:44:27,280 --> 00:44:29,640 Well, probably not. 788 00:44:29,640 --> 00:44:33,320 I'm going to demonstrate this now with the help of my volunteer here, 789 00:44:33,320 --> 00:44:37,400 sausage man. OK. Now, sausage man is made of the same sort of things 790 00:44:37,400 --> 00:44:40,240 that I'm made up of. He's made up of meat, of course. 791 00:44:40,240 --> 00:44:43,440 And I'm just going... We've connected him to a heating wire. 792 00:44:43,440 --> 00:44:46,520 I'm just going to turn up this heating wire here. So, there we are. 793 00:44:46,520 --> 00:44:48,320 The heating wire is just... 794 00:44:48,320 --> 00:44:51,760 Just turn it on a very low voltage there. 795 00:44:51,760 --> 00:44:53,440 It's just beginning to heat up. 796 00:44:53,440 --> 00:44:55,840 Now, it's not really causing too much of a problem. 797 00:44:55,840 --> 00:45:00,080 But watch what happens if I increase the amount of oxygen in the air. 798 00:45:00,080 --> 00:45:02,800 Again, we're going to use the liquid oxygen to do this. 799 00:45:02,800 --> 00:45:08,000 It's just to provide a lot of oxygen gas in the environment. 800 00:45:08,000 --> 00:45:11,080 So he's just with the heating coil there. 801 00:45:11,080 --> 00:45:13,760 Is anything beginning to happen? 802 00:45:13,760 --> 00:45:17,600 His leg's smoking a bit as the wire's heating. 803 00:45:17,600 --> 00:45:19,840 So this is like you're on a different planet 804 00:45:19,840 --> 00:45:23,000 and there's a lot of oxygen on the planet here. 805 00:45:23,000 --> 00:45:26,120 You accidentally lean against a cooker... 806 00:45:26,120 --> 00:45:27,920 And look what's happening here. 807 00:45:29,160 --> 00:45:32,400 Poor sausage man is now in flames. 808 00:45:35,280 --> 00:45:40,520 He's gone up rather drastically here. 809 00:45:40,520 --> 00:45:45,000 This is because of the increased oxygen in his environment. 810 00:45:45,000 --> 00:45:47,440 So, yes, of course, we do need oxygen to stay alive. 811 00:45:47,440 --> 00:45:49,400 It does provide us with our energy. 812 00:45:49,400 --> 00:45:54,040 But too much would definitely be a bad thing. 813 00:45:54,040 --> 00:45:57,080 I need to put out our sausage man. I think it might be very difficult 814 00:45:57,080 --> 00:46:00,280 to put him out since there's so much oxygen in there. 815 00:46:00,280 --> 00:46:03,600 Let's try... We've got some tomato ketchup here. 816 00:46:03,600 --> 00:46:05,920 LAUGHTER 817 00:46:05,920 --> 00:46:06,960 It's... 818 00:46:09,400 --> 00:46:10,400 Wow. 819 00:46:14,280 --> 00:46:18,920 It leaks as well. Great. Somebody didn't put the top on properly. 820 00:46:18,920 --> 00:46:20,360 There we are. We've put him out. 821 00:46:23,400 --> 00:46:26,440 Oops. What a mess. OK. 822 00:46:26,440 --> 00:46:28,480 OK. So, you get the idea 823 00:46:28,480 --> 00:46:32,840 that too much oxygen would certainly be bad for us. 824 00:46:32,840 --> 00:46:36,800 But on a serious note, it's incredibly difficult to put out 825 00:46:36,800 --> 00:46:38,240 a forest fire. 826 00:46:38,240 --> 00:46:41,480 These are incredibly difficult to put out, even with just 21% oxygen. 827 00:46:41,480 --> 00:46:45,440 If it was 100% oxygen, there would be no chance. 828 00:46:45,440 --> 00:46:48,800 So 21% of the air is made up of oxygen. 829 00:46:48,800 --> 00:46:50,760 This is how much we need to breathe. 830 00:46:50,760 --> 00:46:54,680 But what happens if you reduce the amount? Can we still stay alive? 831 00:46:54,680 --> 00:46:57,560 Well, I went to a place just outside Cambridge 832 00:46:57,560 --> 00:47:00,240 where they've reduced the amount of oxygen in their rooms there 833 00:47:00,240 --> 00:47:03,040 from 21% down to 15%. 834 00:47:03,040 --> 00:47:06,480 And they say that things just can't burn in this environment. 835 00:47:06,480 --> 00:47:09,120 Well, let's see what happened. Can I have a fire? Yes. 836 00:47:09,120 --> 00:47:11,760 Can I set fire to your newspaper? I've got a newspaper here 837 00:47:11,760 --> 00:47:15,680 and you try to light my newspaper. OK. All right. 838 00:47:16,800 --> 00:47:21,480 See if it works. Shall I use a lighter? Use the lighter. 839 00:47:21,480 --> 00:47:24,320 I'll try the lighter first of all. OK. 840 00:47:27,680 --> 00:47:30,520 Oh. Empty? I don't think it's a very good one. 841 00:47:30,520 --> 00:47:34,720 Try mine if yours is empty. This is a new one, is it? 842 00:47:34,720 --> 00:47:39,120 OK. OK. Doesn't work. Matches. Matches. OK. 843 00:47:39,120 --> 00:47:40,760 Ah! This is better. 844 00:47:40,760 --> 00:47:42,120 OK. Try again. 845 00:47:43,840 --> 00:47:45,880 Of course, the matches are still lighting 846 00:47:45,880 --> 00:47:48,520 because they have their own oxygen built in here. 847 00:47:48,520 --> 00:47:51,560 That's what's allowing them to strike, 848 00:47:51,560 --> 00:47:54,800 but there's not enough oxygen to allow your newspaper 849 00:47:54,800 --> 00:47:57,040 or the match to actually burn. 850 00:47:57,040 --> 00:48:01,400 It's only the match head with oxygen there. Absolutely correct. 851 00:48:01,400 --> 00:48:04,360 The newspaper could not burn by itself. Impossible. 852 00:48:04,360 --> 00:48:07,040 Of course, we can breathe fine in here. It doesn't affect us. 853 00:48:07,040 --> 00:48:10,040 It doesn't affect us at all. We could live in here for ever. 854 00:48:10,040 --> 00:48:11,320 Very impressive. 855 00:48:15,760 --> 00:48:20,400 We've come outside to try a slightly larger-scale version of the lighter. 856 00:48:20,400 --> 00:48:25,320 The lighter couldn't start a fire in the room because it didn't bring 857 00:48:25,320 --> 00:48:28,920 any oxygen with it and there wasn't enough oxygen in the room itself. 858 00:48:28,920 --> 00:48:30,840 So this should... This is petrol. 859 00:48:30,840 --> 00:48:33,400 I've soaked this torch here in petrol. 860 00:48:33,400 --> 00:48:35,640 It should light nice and easily. 861 00:48:35,640 --> 00:48:40,320 Yes. Look at that. So, this is burning rather well. 862 00:48:40,320 --> 00:48:43,160 The question is, will this go out in the room? 863 00:48:44,560 --> 00:48:45,720 Well, let's find out. 864 00:48:59,000 --> 00:49:02,240 And the fire has instantly gone out. 865 00:49:02,240 --> 00:49:07,320 There really just isn't enough oxygen in this room to allow this, 866 00:49:07,320 --> 00:49:09,920 my torch here, to carry on burning. 867 00:49:09,920 --> 00:49:12,920 But there is enough for me to carry on living. 868 00:49:12,920 --> 00:49:14,960 So that's pretty good and I'm happy. 869 00:49:17,320 --> 00:49:21,480 So, this fire prevention system works by decreasing 870 00:49:21,480 --> 00:49:25,360 the amount of oxygen and increasing the amount of nitrogen. 871 00:49:25,360 --> 00:49:28,280 Nitrogen is a very important component of the air 872 00:49:28,280 --> 00:49:32,320 because it's so inert, because of these very strong bonds. 873 00:49:32,320 --> 00:49:34,720 So we're now going to look at some of the properties 874 00:49:34,720 --> 00:49:37,600 of this inert gas, nitrogen. 875 00:49:37,600 --> 00:49:41,320 And this is one of the components in many explosives 876 00:49:41,320 --> 00:49:43,480 such as this nitroglycerin here. 877 00:49:43,480 --> 00:49:46,400 This is a very dangerous explosive. 878 00:49:46,400 --> 00:49:50,200 In fact, Alfred Nobel... 879 00:49:50,200 --> 00:49:57,160 earned his money in trying to work out how to make this more stable. 880 00:49:57,160 --> 00:50:00,320 I need to put on some special kit here, some protective clothing 881 00:50:00,320 --> 00:50:03,520 and some ear protectors. OK. 882 00:50:04,800 --> 00:50:09,280 And I'm going to add a drop of nitroglycerin to the filter paper. 883 00:50:13,760 --> 00:50:17,080 Now then. Adding a drop of nitroglycerin. 884 00:50:17,080 --> 00:50:19,080 There we are. That's it. 885 00:50:23,040 --> 00:50:28,800 And I think I'll just remove this nitroglycerin from here. 886 00:50:28,800 --> 00:50:31,080 I don't want to be too close when this goes off. 887 00:50:32,160 --> 00:50:35,840 So I'll hand this to Mark. Thank you. Right. 888 00:50:35,840 --> 00:50:39,480 Now, the nitroglycerin contains a lot of nitrogen locked up 889 00:50:39,480 --> 00:50:42,800 into its chemical composition. 890 00:50:42,800 --> 00:50:47,760 And it's the sudden release of this that gives it its explosive power. 891 00:50:49,200 --> 00:50:51,800 BANG! 892 00:51:05,120 --> 00:51:06,960 That really was quite violent, 893 00:51:06,960 --> 00:51:10,120 the sudden release of that nitrogen gas. 894 00:51:10,120 --> 00:51:13,680 And that's what makes an explosive explosive. 895 00:51:13,680 --> 00:51:16,200 Most of them contain nitrogen built in. 896 00:51:16,200 --> 00:51:19,800 But remarkably, this reaction, this explosive release of nitrogen gas, 897 00:51:19,800 --> 00:51:24,000 has been used to save thousands of lives. 898 00:51:24,000 --> 00:51:25,960 For this, I need a car. 899 00:51:25,960 --> 00:51:29,120 Have you got a car there, please, Chris? 900 00:51:29,120 --> 00:51:32,760 OK. Well, it's not exactly a real car. 901 00:51:32,760 --> 00:51:36,000 But it is a real steering wheel. OK. 902 00:51:36,000 --> 00:51:39,480 So, this contains a compound with nitrogen in it. 903 00:51:39,480 --> 00:51:41,320 It's nitrogen combined with sodium. 904 00:51:41,320 --> 00:51:43,720 Can we have our periodic table up for a second, please? 905 00:51:43,720 --> 00:51:48,360 So, we have nitrogen over here combined with sodium over here. 906 00:51:48,360 --> 00:51:51,440 But it's the formation of our very, very strong 907 00:51:51,440 --> 00:51:56,120 nitrogen-nitrogen bonds that leads to the rapid inflation 908 00:51:56,120 --> 00:51:57,360 of this air bag. 909 00:51:57,360 --> 00:52:00,800 Now, I need a volunteer from the audience for this, please. 910 00:52:00,800 --> 00:52:03,880 Er, who shall we have? Yes, would you like to come down the front? 911 00:52:03,880 --> 00:52:06,680 Thank you very much. Would you like to stand all the way over here? 912 00:52:06,680 --> 00:52:09,120 And your name is...? Fred. Fred. OK, Fred. 913 00:52:09,120 --> 00:52:11,160 Now, you are going to trigger this air bag. 914 00:52:11,160 --> 00:52:14,400 So if I just take this from Chris. Is this primed? 915 00:52:14,400 --> 00:52:16,840 Just going to make sure it's all OK to trigger. 916 00:52:20,920 --> 00:52:23,720 OK. Thank you very much. Now, if you stand over here. 917 00:52:23,720 --> 00:52:26,720 He's very keen to get a hand on the trigger here. 918 00:52:26,720 --> 00:52:29,240 Now, we're going to count down from three. OK. If you hold this. 919 00:52:29,240 --> 00:52:32,000 Don't press the button yet. OK. Now, when we've counted down, 920 00:52:32,000 --> 00:52:33,440 I want you to press the button. 921 00:52:33,440 --> 00:52:36,120 But don't blink. If you blink, you'll miss this. 922 00:52:36,120 --> 00:52:40,400 It's a very quick reaction. OK. So, three, two, one. 923 00:52:40,400 --> 00:52:43,560 BANG! There we are. 924 00:52:43,560 --> 00:52:46,080 OK. Thank you very much indeed. A round of applause for Fred. 925 00:52:46,080 --> 00:52:48,680 APPLAUSE 926 00:52:48,680 --> 00:52:52,080 So, this air bag works here 927 00:52:52,080 --> 00:52:56,240 because the nitrogen really wants to bond to itself to form 928 00:52:56,240 --> 00:53:00,640 these nitrogen molecules and it's this explosive release of nitrogen 929 00:53:00,640 --> 00:53:04,760 that inflates the air bag so quickly. We can see this here 930 00:53:04,760 --> 00:53:09,440 in slow motion. Actually, when the crash test dummy hits the bag, 931 00:53:09,440 --> 00:53:13,240 this bag is actually deflating. The air is coming out of this. 932 00:53:13,240 --> 00:53:16,640 But it needs to be released so quickly, 933 00:53:16,640 --> 00:53:19,400 that's why an explosive is needed. 934 00:53:19,400 --> 00:53:21,640 So nitrogen here saving lives. 935 00:53:21,640 --> 00:53:24,640 But actually, nitrogen is vital for life. 936 00:53:24,640 --> 00:53:26,480 We couldn't live without it. 937 00:53:26,480 --> 00:53:31,600 Every protein in every cell in our body is made up of amino acids. 938 00:53:31,600 --> 00:53:35,040 And every one of these amino acids contains nitrogen. 939 00:53:35,040 --> 00:53:37,680 So somehow we need to take the nitrogen from the air 940 00:53:37,680 --> 00:53:40,720 and get it to combine with other elements so we can form compounds 941 00:53:40,720 --> 00:53:42,040 that are useful to us. 942 00:53:42,040 --> 00:53:45,200 Now, plants have learnt how to do this over millions of years, 943 00:53:45,200 --> 00:53:47,880 but it took chemists a long time to do this. 944 00:53:47,880 --> 00:53:51,960 And the first way this was achieved was by emulating nature... 945 00:53:51,960 --> 00:53:53,960 THUNDER ..a process in nature 946 00:53:53,960 --> 00:53:57,320 where nitrogen and oxygen are beginning to react. 947 00:53:57,320 --> 00:53:59,040 During this electrical storm, 948 00:53:59,040 --> 00:54:02,840 the lightning here is providing sufficient energy to split apart 949 00:54:02,840 --> 00:54:06,920 these molecules and this can allow nitrogen and oxygen to recombine. 950 00:54:06,920 --> 00:54:11,120 We're going to try and do this in the lecture now. And I have... 951 00:54:11,120 --> 00:54:13,840 Well, this is what every mad scientist should have. 952 00:54:13,840 --> 00:54:17,120 It's a Jacob's ladder and here we see it switched on. 953 00:54:17,120 --> 00:54:19,920 So what we're doing here is passing thousands of volts 954 00:54:19,920 --> 00:54:24,640 between these two electrodes and this is causing the molecules 955 00:54:24,640 --> 00:54:28,040 in the air to be ripped apart, ripping their electrons out. 956 00:54:28,040 --> 00:54:30,080 This heats up the air just above it, 957 00:54:30,080 --> 00:54:33,040 making it easier to pass the electric current through that, 958 00:54:33,040 --> 00:54:35,720 which is why this thing is gradually rising. 959 00:54:35,720 --> 00:54:40,480 But how will we know if there is any chemical reaction taking place here? 960 00:54:40,480 --> 00:54:43,080 Well, we're going to keep an eye on this 961 00:54:43,080 --> 00:54:46,360 and look for signs of a reaction. We should see a colour change. 962 00:54:46,360 --> 00:54:49,360 Now, I can demonstrate the colour change that we're going to see. 963 00:54:49,360 --> 00:54:51,360 I have two flasks here. 964 00:54:51,360 --> 00:54:54,440 This contains a compound called nitric oxide. 965 00:54:54,440 --> 00:54:56,480 This is just air. 966 00:54:56,480 --> 00:54:59,120 But when the two come together... 967 00:55:00,240 --> 00:55:01,200 ..we form... 968 00:55:03,880 --> 00:55:08,560 ..a new compound that we can see, that isn't colourless. 969 00:55:08,560 --> 00:55:12,960 There we are. And this is the gas nitrogen dioxide. 970 00:55:12,960 --> 00:55:17,440 So, this is what we're looking for in our Jacob's ladder. 971 00:55:17,440 --> 00:55:20,120 So the nitrogen, if it combines with the oxygen, 972 00:55:20,120 --> 00:55:25,200 we may be able to see this coloured gas nitrogen dioxide. 973 00:55:25,200 --> 00:55:29,400 We'll keep an eye on the tube there. It just contains air. 974 00:55:29,400 --> 00:55:32,280 I'll just get rid of that. 975 00:55:32,280 --> 00:55:36,640 But this isn't really real lightning. 976 00:55:36,640 --> 00:55:38,880 This is only a very small spark here. 977 00:55:38,880 --> 00:55:42,240 We can maybe begin to see hints of some colour change, 978 00:55:42,240 --> 00:55:45,000 but we'll keep an eye on it. We need a bigger spark. 979 00:55:45,000 --> 00:55:48,680 We need something to produce about a million volts. 980 00:55:48,680 --> 00:55:51,320 And this is what this is for. 981 00:55:51,320 --> 00:55:53,280 This is a Tesla coil 982 00:55:53,280 --> 00:55:57,040 and it can generate a million volts. 983 00:55:57,040 --> 00:55:59,480 We've had some problems with this bit of kit. 984 00:55:59,480 --> 00:56:03,320 It basically fries all the cameras, all the electrics, all the lights. 985 00:56:03,320 --> 00:56:08,400 So this really should give us some rather impressive lightning. 986 00:56:08,400 --> 00:56:11,760 Now, I must ask everyone just to remain in your seats 987 00:56:11,760 --> 00:56:14,480 for this demonstration. Let's see how we go. 988 00:56:19,560 --> 00:56:21,600 BUZZING 989 00:56:49,400 --> 00:56:52,080 Phew. 990 00:56:52,080 --> 00:56:54,520 CHEERING AND APPLAUSE 991 00:56:59,720 --> 00:57:03,640 That really... That really is quite nerve-racking, I must say. 992 00:57:03,640 --> 00:57:06,320 And what we are seeing here with all that energy 993 00:57:06,320 --> 00:57:09,080 was causing the nitrogen molecules and the oxygen molecules 994 00:57:09,080 --> 00:57:11,560 to be ripped apart and then they recombine 995 00:57:11,560 --> 00:57:14,800 to form nitrogen dioxide and that's what we can see, 996 00:57:14,800 --> 00:57:17,840 this brown colour here now in our Jacob's ladder. 997 00:57:17,840 --> 00:57:20,240 And we can also form molecules of ozone. 998 00:57:20,240 --> 00:57:23,960 That's three oxygen atoms together. So, what have we learnt here? 999 00:57:23,960 --> 00:57:27,800 We've learnt that the air is more complicated than we ever thought. 1000 00:57:27,800 --> 00:57:30,760 The alchemists thought it was made up of just one element 1001 00:57:30,760 --> 00:57:34,440 but they were wrong. It's made up of a number of different elements, 1002 00:57:34,440 --> 00:57:38,600 of nitrogen, oxygen. We've seen how important they are to our lives. 1003 00:57:38,600 --> 00:57:40,720 Without the oxygen, we'd all be dead. 1004 00:57:40,720 --> 00:57:43,040 But with too much, we couldn't survive either. 1005 00:57:43,040 --> 00:57:46,880 We've also seen how the very rare gases, the noble gases, can be used 1006 00:57:46,880 --> 00:57:49,360 to save lives in hospitals. 1007 00:57:49,360 --> 00:57:53,800 Now, the alchemists spent their lives trying to master the elements. 1008 00:57:53,800 --> 00:57:56,280 But they only scratched the surface. 1009 00:57:56,280 --> 00:57:58,360 They might have been able to play with fire, 1010 00:57:58,360 --> 00:58:01,560 but they couldn't control it or understand what it was made of. 1011 00:58:01,560 --> 00:58:04,920 Nor could they pick out the elements from the air and use them 1012 00:58:04,920 --> 00:58:06,920 to make the world a better place. 1013 00:58:06,920 --> 00:58:10,720 This is where the modern alchemist takes over. 1014 00:58:10,720 --> 00:58:13,920 Join us in the next lecture where we'll investigate 1015 00:58:13,920 --> 00:58:16,560 how a glass of water contains the remnants 1016 00:58:16,560 --> 00:58:19,200 of the most violent reactions in the world. 1017 00:58:19,200 --> 00:58:20,400 Good night. Thank you. 1018 00:58:24,160 --> 00:58:27,120 Subtitles by Red Bee Media Ltd 91768

Can't find what you're looking for?
Get subtitles in any language from opensubtitles.com, and translate them here.