0:00:00 > 0:00:04The alchemists were a mysterious group of medieval scientists
0:00:04 > 0:00:08who believed their knowledge of chemistry gave them magical powers.
0:00:08 > 0:00:12They could summon fire, produce mystical potions.
0:00:12 > 0:00:17They even tried to turn metals into gold.
0:00:18 > 0:00:23Their magnificent feats enthralled kings and commoners alike.
0:00:23 > 0:00:26But they never revealed their secrets.
0:00:26 > 0:00:28By pushing the frontiers of science,
0:00:28 > 0:00:30modern chemists can perform equally impressive feats,
0:00:30 > 0:00:33and we're happy to tell you everything.
0:00:54 > 0:00:56APPLAUSE
0:01:04 > 0:01:07Chemistry gives us an understanding of the world
0:01:07 > 0:01:10that the other sciences just don't.
0:01:10 > 0:01:14It's all about how one substance interacts with another
0:01:14 > 0:01:16to give us something new.
0:01:16 > 0:01:21Thank you. Take this Christmas tree here, for instance.
0:01:21 > 0:01:27A nice, solid structure, but watch what happens when I do this.
0:01:29 > 0:01:31Whoa!
0:01:35 > 0:01:36APPLAUSE
0:01:43 > 0:01:47Well, we certainly saw that a change took place there.
0:01:47 > 0:01:51That was a flash of light, I felt a blast of heat,
0:01:51 > 0:01:55heard a whoosh of sound and then nothing was left at all.
0:01:55 > 0:01:57Trying to understand what happens
0:01:57 > 0:02:01when one thing changes into another is chemistry.
0:02:01 > 0:02:05My name is Dr Peter Wothers, and I am a chemist.
0:02:05 > 0:02:06APPLAUSE
0:02:09 > 0:02:13Now, the ancient Greeks thought that everything around them
0:02:13 > 0:02:15was made up of just four elements.
0:02:15 > 0:02:18Air, water, earth and fire.
0:02:18 > 0:02:20We see these here.
0:02:20 > 0:02:23In the next three lectures, we're going to look at what air,
0:02:23 > 0:02:26water and earth are really made up of.
0:02:26 > 0:02:31But don't worry, there will be plenty of fire in all of the lectures.
0:02:31 > 0:02:34But this brings me to one important point.
0:02:34 > 0:02:38Please do not try these experiments at home.
0:02:38 > 0:02:41By understanding the elements around us,
0:02:41 > 0:02:43the modern building blocks of science,
0:02:43 > 0:02:46we need to look at the world in a different way,
0:02:46 > 0:02:50we need to see these elements through the eyes of a chemist.
0:02:50 > 0:02:51By understanding these elements,
0:02:51 > 0:02:55we can make better materials and better medicines for our future.
0:02:55 > 0:02:59We're going to start this first lecture looking at the air.
0:02:59 > 0:03:03Now, of course, this is something that we rarely think about,
0:03:03 > 0:03:05but without it, we'd all be dead.
0:03:05 > 0:03:07But just to show you that it really is here around us
0:03:07 > 0:03:10pushing down on this, I've got a demonstration,
0:03:10 > 0:03:13but I'd like a volunteer from the audience, please.
0:03:13 > 0:03:15Right on the corner there, at the back, yes,
0:03:15 > 0:03:18would you like to come down to the front, please?
0:03:21 > 0:03:24- OK. Now. What's your name, please? - Xavier.- Xavier. OK.
0:03:24 > 0:03:26Right. So, see this here? This is just a normal oil drum.
0:03:26 > 0:03:29It seems to be covered in a bit of rubbish.
0:03:29 > 0:03:33Hold this, give it a good whack.
0:03:33 > 0:03:35Go on, bit harder than that. OK.
0:03:35 > 0:03:38It really is quite solid, isn't it? On the top as well, maybe. OK.
0:03:38 > 0:03:40- Yeah. Do you think it's pretty solid?- Yeah.
0:03:40 > 0:03:45Now, watch what happens when we take the air out of this drum.
0:03:45 > 0:03:48At the moment, there is of course a scope open at the top here,
0:03:48 > 0:03:51there's air inside, air outside, but we're going to put this pump on here
0:03:51 > 0:03:56so we're now removing the air from this drum.
0:03:56 > 0:04:01OK. And... That's good. I think you should just step back. That's it.
0:04:01 > 0:04:04You stand over there. I'll stand over here.
0:04:04 > 0:04:08OK, so we're removing the air from the inside of this drum.
0:04:08 > 0:04:11To start off with, the air molecules were pushing
0:04:11 > 0:04:16against the drum, but they're also pushing from the outside as well.
0:04:16 > 0:04:20So what do you think will happen if we remove the air from inside?
0:04:20 > 0:04:22- Any ideas?- It will shrink. - It will shrink?
0:04:22 > 0:04:25So do you think it will gradually shrink up and get smaller?
0:04:25 > 0:04:28Yeah? Well, that's a good idea. That's what we think.
0:04:28 > 0:04:31It doesn't seem to be doing very much at the moment, does it?
0:04:31 > 0:04:32So, not a lot.
0:04:32 > 0:04:36Well, supposedly, these little air molecules
0:04:36 > 0:04:40are all pushing down on this can here. We're taking...
0:04:40 > 0:04:41BANG!
0:04:41 > 0:04:43GASPING
0:04:52 > 0:04:57Come and have a look. You feel that. It is very solid, isn't it?
0:04:57 > 0:05:00- Yeah.- That was just the air.
0:05:00 > 0:05:03So we do forget about it, but it really is pushing down on us.
0:05:03 > 0:05:04It's quite a strong force.
0:05:04 > 0:05:08It's like there's two full-grown men standing on your shoulders.
0:05:08 > 0:05:11We don't notice it because we're used to it, we've adapted to it.
0:05:11 > 0:05:14Thank you very much. Give him a round of applause. Thank you.
0:05:14 > 0:05:16APPLAUSE
0:05:21 > 0:05:25But what about our tree? What happened to the tree?
0:05:25 > 0:05:28Well, what would the ancient Greeks have thought if they had seen that?
0:05:28 > 0:05:32What would they have made of this strange substance?
0:05:32 > 0:05:35Well, this, actually, the Greeks never saw.
0:05:35 > 0:05:37This is a substance called guncotton.
0:05:37 > 0:05:40It was only discovered around 200 years ago.
0:05:40 > 0:05:42It's quite remarkable.
0:05:42 > 0:05:47The Greeks would've said that this is changing into fire and air.
0:05:47 > 0:05:50Maybe they would've said this is made of fire and air.
0:05:50 > 0:05:54Or maybe they would've just said it's magic.
0:05:54 > 0:05:56Either way, they would be wrong.
0:05:56 > 0:05:59We now know that the air is much more complicated.
0:05:59 > 0:06:03It's a mixture of different components.
0:06:03 > 0:06:07To show exactly what the air is made up of, again I need a volunteer.
0:06:07 > 0:06:09There's a hand very quickly. I saw your hand.
0:06:09 > 0:06:12Would you like to come down, please? Thank you.
0:06:12 > 0:06:14Can we have a round of applause, please?
0:06:15 > 0:06:19- OK, your hand shot up very quickly there. What's your name?- Nadia.
0:06:19 > 0:06:23Nadia. OK, excellent. Now, have you made air before?
0:06:23 > 0:06:25Oh, having to think about that one.
0:06:25 > 0:06:29- Have you made air before, mixed it up?- No.- Exactly.
0:06:29 > 0:06:31Of course, the alchemist would never have done this, either.
0:06:31 > 0:06:34They didn't know what was in the air. Do you know what's in the air?
0:06:34 > 0:06:38- No.- No. No? Oh, come on, have a guess. Do you know any of the gases?
0:06:38 > 0:06:42- Oxygen.- Very good, you see, oxygen. Do you know any other ones?
0:06:42 > 0:06:44- Carbon dioxide. - Carbon dioxide, exactly.
0:06:44 > 0:06:47So we're going to see how many of the different gases are in air.
0:06:47 > 0:06:48Would you like to come over here?
0:06:48 > 0:06:50So these are some gas cylinders,
0:06:50 > 0:06:53and we've got the different proportions of the air
0:06:53 > 0:06:55you're going to add to this cylinder of water here.
0:06:55 > 0:06:58OK. Now, the first one is the most common gas.
0:06:58 > 0:07:01It's not oxygen, and it's not carbon dioxide. Does anybody else know?
0:07:01 > 0:07:03- Do you want to shout it out? - Nitrogen.
0:07:03 > 0:07:06Nitrogen. Yes, exactly. So the most common gas is nitrogen,
0:07:06 > 0:07:08and this is what we have here,
0:07:08 > 0:07:10so I'd like you to turn the tap for me, please. This tap here.
0:07:10 > 0:07:13This is going to let some nitrogen in.
0:07:13 > 0:07:17Now, we're aiming to get to this mark here.
0:07:17 > 0:07:22This is 78%. If we get up to here, it's 100%. That'd be 78% nitrogen.
0:07:22 > 0:07:25So, there's a lot of nitrogen in the air, isn't there?
0:07:25 > 0:07:27There's all this. Look at this. You've got to stop it.
0:07:27 > 0:07:31You've got to get this red mark here on the black mark,
0:07:31 > 0:07:32so you've got to get this just right.
0:07:32 > 0:07:37This is our nitrogen, and this is going to be 78%.
0:07:38 > 0:07:43- Oh, stop, stop, stop, stop, stop, stop, stop! You've gone past.- Sorry!
0:07:43 > 0:07:47Oh, dear, what a disaster. That's OK. Look, there we are.
0:07:47 > 0:07:49There we are. Spot on.
0:07:49 > 0:07:5378%. Well done, that's fantastic. Excellent. OK.
0:07:53 > 0:07:56Now then, the next ingredient, what's the next ingredient?
0:07:56 > 0:08:00- Nitrogen? Oh, sorry.- We've done nitrogen. What's the next one?
0:08:00 > 0:08:03- Carbon dioxide.- No. You like your carbon dioxide.- Oxygen.- It's oxygen.
0:08:03 > 0:08:06You're absolutely right. Very important one.
0:08:06 > 0:08:10Right. So this is our oxygen. OK? You're absolutely right there.
0:08:10 > 0:08:12- You ready to go again?- Yeah. - Not yet, not yet.
0:08:12 > 0:08:15We've got to go to 21%.
0:08:15 > 0:08:19Now, 21%, that takes us to about here,
0:08:19 > 0:08:24I think. OK, that's 21-ish. Yes. So you're aiming for here, OK?
0:08:24 > 0:08:26Go on, then.
0:08:26 > 0:08:28That's it. Very good.
0:08:30 > 0:08:33So there's quite a lot of oxygen as well.
0:08:33 > 0:08:37I can see the concentration now. That's what we need. Very good.
0:08:37 > 0:08:41Oh, look at that. Just about spot on again.
0:08:41 > 0:08:44Remarkable. OK. Very good.
0:08:44 > 0:08:48Now, then. Now, we're coming to the third most abundant gas.
0:08:48 > 0:08:54So far, we've got 78% nitrogen, we've got 21% oxygen.
0:08:54 > 0:08:59We've almost run out of everything else. That's only 1% left.
0:08:59 > 0:09:02Does anyone know the third most abundant gas?
0:09:02 > 0:09:05You haven't mentioned this one yet. Does anybody know? Shout it out.
0:09:05 > 0:09:07SHOUTING
0:09:07 > 0:09:11All sorts of different replies there, but it is, in fact, argon.
0:09:11 > 0:09:14I think some people said argon. Pat yourself on the back there.
0:09:14 > 0:09:15It is argon. Right.
0:09:15 > 0:09:17This is a tricky one now, but you're getting very good.
0:09:17 > 0:09:21All right. Argon. This is just 1%, so that's about there.
0:09:21 > 0:09:24- Can you see that?- Yeah.- About here, here it is, OK?
0:09:24 > 0:09:28- OK.- Go on, then. Go on.
0:09:28 > 0:09:31Oh, wrong one. The audience are watching. The argon one.
0:09:31 > 0:09:34That's it. Give it a go.
0:09:34 > 0:09:35Brilliant.
0:09:35 > 0:09:39There we are. Look at that. That is very good indeed. Now, then.
0:09:39 > 0:09:40APPLAUSE
0:09:43 > 0:09:46- We're coming to your favourite gas. Which one's that?- Carbon dioxide.
0:09:46 > 0:09:49Carbon dioxide, exactly. But there's not a lot of carbon dioxide.
0:09:49 > 0:09:54In fact, it's 0.037% carbon dioxide.
0:09:54 > 0:09:57Unless we did this 200 years ago, it would've been quite a bit less.
0:09:57 > 0:09:58We've increased the amount, but anyway...
0:09:58 > 0:10:03So carbon dioxide, we just need a quick burst from that, so quick burst. That's it. That'll do.
0:10:03 > 0:10:04That's your carbon dioxide.
0:10:04 > 0:10:07Hardly any at all, but nonetheless, very important.
0:10:07 > 0:10:11All the plants need that. So that's our carbon dioxide.
0:10:11 > 0:10:13You still haven't made perfect air yet.
0:10:13 > 0:10:16We could breathe this, that would be OK, but there are some other gases,
0:10:16 > 0:10:17and these are some rather rare gases
0:10:17 > 0:10:20but we've put all of these in this little syringe here.
0:10:20 > 0:10:24Would you like to just add your last bit of gas,
0:10:24 > 0:10:27so just push the plunger down and watch for the bubble.
0:10:27 > 0:10:29That it is, there we are.
0:10:29 > 0:10:32There, excellent. That's the last gases.
0:10:32 > 0:10:35This is neon, helium, krypton, and xenon.
0:10:35 > 0:10:38They make up just a tiny proportion of the gas.
0:10:38 > 0:10:39You did very well there.
0:10:39 > 0:10:42Thank you very much. Give her a big round of applause.
0:10:42 > 0:10:48APPLAUSE
0:10:49 > 0:10:54OK, so now then we know that air isn't just one element,
0:10:54 > 0:10:55but a mixture of many.
0:10:55 > 0:11:00Before we look at these different elements from air in more detail,
0:11:00 > 0:11:03we want to see all of the elements that occur in nature.
0:11:03 > 0:11:04Now this is where you come in.
0:11:04 > 0:11:07You've got your cards here for different elements
0:11:07 > 0:11:09so, if you're a member of the periodic table, get ready,
0:11:09 > 0:11:12but to help us with this, would you please welcome,
0:11:12 > 0:11:16straight from the West End, the cast of the musical Loserville?
0:11:16 > 0:11:22APPLAUSE
0:11:26 > 0:11:29# There's antimony, arsenic, aluminium, selenium
0:11:29 > 0:11:31# And hydrogen and oxygen and nitrogen and rhenium
0:11:31 > 0:11:34# And nickel, neodymium, neptunium, germanium
0:11:34 > 0:11:35# Iron, americium, ruthenium, uranium
0:11:35 > 0:11:37# Europium, zirconium, lutetium, vanadium
0:11:37 > 0:11:40# And lanthanum and osmium and astatine and radium
0:11:40 > 0:11:43# And gold and protactinium and indium and gallium
0:11:43 > 0:11:47# And iodine and thorium and thulium and thallium
0:11:47 > 0:11:50# There's yttrium, ytterbium, actinium, rubidium
0:11:50 > 0:11:52# And boron, gadolinium, niobium, iridium
0:11:52 > 0:11:54# And strontium and silicon and silver and samarium
0:11:54 > 0:11:57# And bismuth, bromine, lithium, beryllium, and barium... #
0:11:57 > 0:11:58Barium - very good!
0:12:02 > 0:12:05# There's holmium and helium and hafnium and erbium
0:12:05 > 0:12:07# And phosphorus and francium and fluorine and terbium
0:12:07 > 0:12:09# And manganese and mercury, molybdenum, magnesium
0:12:09 > 0:12:11# Dysprosium and scandium and cerium and cesium
0:12:11 > 0:12:14# And lead, praseodymium and platinum, plutonium
0:12:14 > 0:12:16# Palladium, promethium, potassium, polonium
0:12:16 > 0:12:19# And tantalum, technetium, titanium, tellurium,
0:12:19 > 0:12:22# And cadmium and calcium and chromium and curium
0:12:23 > 0:12:25# There's sulphur, californium and fermium, berkelium
0:12:25 > 0:12:28# And also mendelevium, einsteinium, nobelium
0:12:28 > 0:12:30# And argon, krypton, neon, radon, xenon, zinc and rhodium
0:12:30 > 0:12:33# And chlorine, carbon, cobalt, copper, tungsten, tin and sodium
0:12:35 > 0:12:40# These were the only ones they found back when this song was written
0:12:41 > 0:12:45# There are another 60 - now we'll show you where they're sitting... #
0:12:45 > 0:12:48Stand up, as well? Excellent!
0:12:48 > 0:12:52APPLAUSE
0:12:53 > 0:12:57You did very well. My whole periodic table should be standing now
0:12:57 > 0:13:00but would you please give a round of applause for the cast of Loserville?
0:13:00 > 0:13:05- Thank you very much. - APPLAUSE
0:13:05 > 0:13:08OK, well, that was certainly chaotic
0:13:08 > 0:13:09but you did fantastically well there.
0:13:09 > 0:13:12If you'd like to take your seats.
0:13:12 > 0:13:14Now, what about this sort of random order?
0:13:14 > 0:13:18You were springing up all over the place. Was it really a random order?
0:13:18 > 0:13:20Well, actually, it's not.
0:13:20 > 0:13:23There is some logic behind this, but to understand the logic
0:13:23 > 0:13:26we need to look right into the heart of the atom.
0:13:26 > 0:13:30So atoms, as far as the chemists are concerned at least,
0:13:30 > 0:13:32are made up of three different particles.
0:13:32 > 0:13:36In the heart of the nucleus, there are positively charged protons
0:13:36 > 0:13:40and neutral neutrons. We can see these on the screen.
0:13:40 > 0:13:43So the red ones are the protons, the blue ones are the neutrons.
0:13:43 > 0:13:46But then circling around, we have these electrons.
0:13:46 > 0:13:50It's the protons and the neutrons that give an element its mass,
0:13:50 > 0:13:53make it quite heavy, so if you pick something up and say it's heavy,
0:13:53 > 0:13:55well, that's because of the protons and neutrons.
0:13:55 > 0:13:58But it's these electrons that are right around the outside,
0:13:58 > 0:14:01and whenever you touch anything, what you're touching there is electrons.
0:14:01 > 0:14:05I bet you've never thought of this before, but if we shake hands we're shaking electrons there.
0:14:05 > 0:14:09OK, that's our electrons touching each other there. Anyway, right!
0:14:09 > 0:14:11So, here we have our atom.
0:14:11 > 0:14:13We now understand what atoms are made of
0:14:13 > 0:14:15but what's that got to do with the periodic table?
0:14:15 > 0:14:20Well, what makes an element unique is the number of protons in the atom.
0:14:20 > 0:14:22We don't really care about the neutrons
0:14:22 > 0:14:24and if it's a neutral atom,
0:14:24 > 0:14:27of course the number of protons are balanced by the number of electrons.
0:14:27 > 0:14:30Hydrogen, where are you? If you'd like to stand up, hydrogen.
0:14:30 > 0:14:32You are the first element,
0:14:32 > 0:14:35in fact the most abundant element in the universe.
0:14:35 > 0:14:39You've got one proton. That's what makes you hydrogen.
0:14:39 > 0:14:43One proton and one electron for the neutral atom. Sometimes neutrons but we don't care about those.
0:14:43 > 0:14:46The next element, on the same row, we go all the way round to here
0:14:46 > 0:14:51and we find helium. You have two protons - that's what makes you you.
0:14:51 > 0:14:56Then we come back over here to the periodic table. You're very good.
0:14:56 > 0:14:59Lithium, you've got three protons and that's what makes you you, and so on.
0:14:59 > 0:15:01That's what we do when we go from one element to the next.
0:15:01 > 0:15:04We increase the number of protons by one and the number of electrons
0:15:04 > 0:15:07in the neutral atom, and maybe throw in a few neutrons.
0:15:07 > 0:15:11Now, the question is, though, we've got 118 elements
0:15:11 > 0:15:16but we've got literally tens of millions of different compounds
0:15:16 > 0:15:22so how can we get such complexity out of just these 118 elements?
0:15:22 > 0:15:25In fact, in this cup of coffee alone,
0:15:25 > 0:15:29over 2,000 different compounds have been detected so far -
0:15:29 > 0:15:34so loads of compounds, only 118 elements.
0:15:34 > 0:15:40There's a nice analogy between letters and words with these elements and their compounds
0:15:40 > 0:15:43so I could be saying hundreds of thousands of different words now
0:15:43 > 0:15:47but these are all made up of the same 26 letters of the alphabet.
0:15:47 > 0:15:52Words like "I" and "a" are made up with a single letter.
0:15:52 > 0:15:55There are some words that have two of the same letter.
0:15:55 > 0:15:58Aa is a type of Hawaiian lava.
0:15:58 > 0:16:01What a silly word that is. But then there's another Hawaiian word.
0:16:01 > 0:16:04This is aaa, or something like that,
0:16:04 > 0:16:07which is an insect also found in Hawaii.
0:16:09 > 0:16:10Our elements have the same sort of thing.
0:16:10 > 0:16:13The letters then correspond to the elements,
0:16:13 > 0:16:17and there are some elements that just stay by themselves, like these letters.
0:16:17 > 0:16:22Helium, can you put your card up, please? Where are you? There you are. And neon, and argon.
0:16:22 > 0:16:24All of you, you just stay by yourselves,
0:16:24 > 0:16:26just single letters if you like. Single elements.
0:16:26 > 0:16:31Then we have other elements that go around in pairs. Where's nitrogen? Put your card up.
0:16:31 > 0:16:33Oxygen, fluorine, all of you go around in pairs.
0:16:33 > 0:16:37Chlorine, you go around in pairs as well, so you go around in pairs
0:16:37 > 0:16:41and occasionally oxygen - just stand up again, oxygen - occasionally
0:16:41 > 0:16:44you have three oxygen atoms that make up a molecule of ozone.
0:16:44 > 0:16:46OK, thank you very much, elements.
0:16:46 > 0:16:48But most of the periodic table,
0:16:48 > 0:16:52you are loads of these single atoms together, joined together to form
0:16:52 > 0:16:57big masses of metal or non-metals, or whatever you are, if you're solid.
0:16:57 > 0:17:00So this would be like a word like "aaaaa" going on for ever,
0:17:00 > 0:17:02with so many letters we couldn't count them.
0:17:02 > 0:17:04That's not how we usually find the elements.
0:17:04 > 0:17:05How we usually find them
0:17:05 > 0:17:09is combined with one another to form compounds
0:17:09 > 0:17:13so if the letters correspond to our elements,
0:17:13 > 0:17:15the words that we use,
0:17:15 > 0:17:19these correspond to different combinations of the elements - these are the compounds.
0:17:19 > 0:17:24So, the elements want to combine with one another to form different
0:17:24 > 0:17:27molecules and we are going to try an experiment now to show this,
0:17:27 > 0:17:30to show the combination of two elements
0:17:30 > 0:17:33and this is the element oxygen, one of the elements from the air.
0:17:33 > 0:17:34Oxygen, where are you again?
0:17:34 > 0:17:37There's oxygen. And between phosphorus. Phosphorus.
0:17:37 > 0:17:39Can you please stand up, phosphorus.
0:17:39 > 0:17:45- OK, now, do you know how you were first discovered, phosphorus?- No.
0:17:45 > 0:17:48OK, well, we'll give you a bit of a clue. What's your symbol?
0:17:48 > 0:17:49P.
0:17:49 > 0:17:53P. Any idea? No? Does anyone else know?
0:17:53 > 0:17:55OK, there's a chap right at the back there.
0:17:55 > 0:17:59- So where do you think phosphorus was first discovered?- From wee.
0:17:59 > 0:18:01From wee, yes, exactly.
0:18:01 > 0:18:04OK, so thank you, phosphorus. You can take a seat now.
0:18:04 > 0:18:08I've got some urine here - it's only mine so it's not too bad.
0:18:08 > 0:18:10AUDIENCE: Eurgh!
0:18:10 > 0:18:12It's all right! Smells quite nice.
0:18:12 > 0:18:14Do you want a sniff? Oh, you do! OK!
0:18:14 > 0:18:18LAUGHTER
0:18:18 > 0:18:21It's fine!
0:18:21 > 0:18:23Don't worry - it's only apple juice, really!
0:18:23 > 0:18:25But...OK,
0:18:25 > 0:18:29but back in 1669,
0:18:29 > 0:18:33the German alchemist Hennig Brand did take his own urine
0:18:33 > 0:18:38and he heated this up and this amazing substance came out.
0:18:38 > 0:18:41This was phosphorus. How come phosphorus was discovered so early?
0:18:41 > 0:18:44Not just because it was disgusting,
0:18:44 > 0:18:46but also because once you found it you couldn't miss it.
0:18:46 > 0:18:50It just screams out to you, "Here I am!"
0:18:50 > 0:18:51OK, let's try this.
0:18:51 > 0:18:54We've got some phosphorus in this flask here
0:18:54 > 0:18:56and I'm just going to let the air into this.
0:18:56 > 0:18:59We've removed the air and heated up the phosphorus,
0:18:59 > 0:19:00and watch what happens here.
0:19:00 > 0:19:03Maybe we can have the lights down just a little bit here.
0:19:05 > 0:19:11So, as soon as the air comes in, it combines with the phosphorus.
0:19:15 > 0:19:19This is phosphorus reacting with air,
0:19:19 > 0:19:23and this amazed the alchemists.
0:19:23 > 0:19:25When they saw this, they were truly stunned.
0:19:25 > 0:19:29In fact, they were so impressed by this amazing light
0:19:29 > 0:19:33that the reaction has given out, they named this element phosphorus,
0:19:33 > 0:19:37which means "the light giver".
0:19:37 > 0:19:45This discovery was commemorated with a painting by Joseph Wright of Derby, that's on the screen here.
0:19:45 > 0:19:47It has a really catchy title.
0:19:47 > 0:19:51It's called "the alchemist in search of the philosopher's stone
0:19:51 > 0:19:54"discovers phosphorus and prays for the successful conclusion
0:19:54 > 0:20:00"of his operation, as was the custom of the ancient chemical astrologers".
0:20:00 > 0:20:04Snappy, but it sort of says what it is, and you can see this,
0:20:04 > 0:20:09this amazing look in the alchemist's eyes as he's made this fantastic discovery.
0:20:09 > 0:20:13This was far brighter than any of their lamps or candles at the time.
0:20:13 > 0:20:17I have a description here. This is from a book from 1692.
0:20:17 > 0:20:19It describes phosphorus.
0:20:19 > 0:20:22It says you need to store it underwater because it reacts with the air,
0:20:22 > 0:20:23but it also says here,
0:20:23 > 0:20:30"If the Privy Parts be therewith rubb'd, they will be inflamed and burning a good while after."
0:20:31 > 0:20:35Now there's one that you really shouldn't try at home!
0:20:35 > 0:20:41Please don't go smearing phosphorus on your privy parts. It's not fun.
0:20:41 > 0:20:46Anyway, but the alchemists made this discovery. They found phosphorus.
0:20:46 > 0:20:49They knew it was reacting with the air
0:20:49 > 0:20:51but they didn't understand fully what was going on
0:20:51 > 0:20:54because they didn't know what the air was made of.
0:20:56 > 0:20:59Chemists now know that it's a mixture of gases
0:20:59 > 0:21:01and a mixture of different elements that makes up the air.
0:21:01 > 0:21:05Now, we're going to have a look again at the different gases that are in the air.
0:21:05 > 0:21:09In fact, first of all, can we have all the elements that are gases?
0:21:09 > 0:21:11So, all the gaseous atoms. Can you stand up, please?
0:21:11 > 0:21:15So, where are all the atoms that are gases? We have hydrogen over here.
0:21:15 > 0:21:18Well, it's a good job there's not too much of you in the air
0:21:18 > 0:21:21because that would make it very flammable, so if you sit down.
0:21:21 > 0:21:23It would all explode if there was too much hydrogen
0:21:23 > 0:21:25and that wouldn't be very good at all. Who else?
0:21:25 > 0:21:28Nitrogen and oxygen, we know you're the major components,
0:21:28 > 0:21:30but we've also got fluorine and chlorine.
0:21:30 > 0:21:32Fluorine and chlorine, you are incredibly reactive,
0:21:32 > 0:21:36which also makes you incredibly toxic so it's a very good thing
0:21:36 > 0:21:39that you're not in the air as well so perhaps you can sit down as well, please.
0:21:39 > 0:21:42Look where the gases that we do find in the air are.
0:21:42 > 0:21:45We've got nitrogen and oxygen, we've seen you, but then we've got
0:21:45 > 0:21:49all of you sitting here - well, standing here - with the white cards.
0:21:49 > 0:21:54You are the so-called noble gases. Why are you all sitting together?
0:21:54 > 0:21:58This is not a coincidence, it's because you all have very similar
0:21:58 > 0:22:02chemical properties and there's this amazing pattern when we arrange
0:22:02 > 0:22:05the elements in a certain way, that every so often
0:22:05 > 0:22:10elements with the same chemical properties are found grouped together.
0:22:10 > 0:22:13So if we just have our periodic tables up, please.
0:22:13 > 0:22:15That's it, fantastic, very good.
0:22:15 > 0:22:17We can see these coloured patterns here.
0:22:17 > 0:22:20What a beautiful display this is. Excellent.
0:22:20 > 0:22:22All of you with the purple cards here, you are group one.
0:22:22 > 0:22:26You're all really reactive metals, you explode with water.
0:22:26 > 0:22:28Really violently, OK?
0:22:28 > 0:22:31You all have similar properties, you're all grouped together.
0:22:31 > 0:22:34If we come over here, all you with the green cards for instance,
0:22:34 > 0:22:36you're called the halogens.
0:22:36 > 0:22:38You're really poisonous, rather unpleasant substances,
0:22:38 > 0:22:41but you combine with these over here with the alkali metals,
0:22:41 > 0:22:44and you form salts very violently indeed.
0:22:44 > 0:22:46OK, at ease, periodic table.
0:22:46 > 0:22:50We're going to look, though, at our noble gases.
0:22:50 > 0:22:55So, if everyone sits down, but I'd like the noble gases now to come down to the front.
0:22:55 > 0:23:00We've got some samples for you. A balloon of krypton.
0:23:00 > 0:23:02Hold the string and hold it out. Beautiful.
0:23:02 > 0:23:06OK. Xenon, again, hold the string, there we are.
0:23:06 > 0:23:11And then we come... Ah! We have a slight problem with radon, I'm afraid.
0:23:11 > 0:23:13Radon is incredibly radioactive
0:23:13 > 0:23:17so health and safety wouldn't let us give you a balloon full of radon.
0:23:17 > 0:23:22You would go home glowing, so we'll just put this one on you there.
0:23:22 > 0:23:23That's great.
0:23:25 > 0:23:29And ununoctium, I'm afraid ununoctium hasn't even got a name
0:23:29 > 0:23:34and this is because there's so few atoms of ununoctium that were made,
0:23:34 > 0:23:36or we're not even sure if they were made,
0:23:36 > 0:23:39but we couldn't fill a balloon full of you. But you got a balloon anyway!
0:23:39 > 0:23:44LAUGHTER
0:23:44 > 0:23:47OK, so, mm-hmm, right.
0:23:47 > 0:23:49Now, you've all got your balloons
0:23:49 > 0:23:52and after a countdown from three, I'd like you to release your balloons.
0:23:52 > 0:23:56Keep hold of the strings, though, and we'll see what happens.
0:23:56 > 0:23:57So three, two, one, go.
0:23:58 > 0:24:01Ah! Look at that. Now, what do we see here?
0:24:01 > 0:24:03We all know that helium balloons float
0:24:03 > 0:24:07so you've got a nice light element there, helium. What about this neon?
0:24:07 > 0:24:12Neon, hmm, it's about the same. You've dropped your string.
0:24:12 > 0:24:16Keep hold of the string. It's about the same sort of density as air.
0:24:16 > 0:24:22It's the balloon that's making it sink. Argon is getting pretty, er... Whoops! More dense there.
0:24:22 > 0:24:26Keep hold, thank you. Krypton is really quite heavy.
0:24:26 > 0:24:31And xenon, hmm, you wouldn't want to go to a party with that, would you?
0:24:31 > 0:24:33You would be dragging this along the floor!
0:24:33 > 0:24:36It's a very expensive gas - it's about £100, this balloon,
0:24:36 > 0:24:40but yes, it's very heavy indeed. What does this tell us, though?
0:24:40 > 0:24:45Each of these balloons actually has the same number of atoms
0:24:45 > 0:24:48because equal volumes contain the same number of particles.
0:24:48 > 0:24:55It tells us that the atoms of helium are much lighter than the atoms of xenon
0:24:55 > 0:24:58and that's because of the subatomic particles that make up these atoms.
0:24:58 > 0:25:02The helium just has two protons and two neutrons
0:25:02 > 0:25:06all the way down to ununoctium - you have 118 protons and loads of neutrons.
0:25:06 > 0:25:08I think you've done fantastically well.
0:25:08 > 0:25:10Would you like to return to your seats? Thank you.
0:25:10 > 0:25:13APPLAUSE
0:25:13 > 0:25:16We've seen that we've got different densities of these gases,
0:25:16 > 0:25:18they have different masses,
0:25:18 > 0:25:20but they also have very similar properties
0:25:20 > 0:25:23and each of these elements is a gas
0:25:23 > 0:25:27and we've filled these signs up with these gases.
0:25:27 > 0:25:28We can see that you're all colourless.
0:25:28 > 0:25:32You're also all odourless gases, which is a good thing.
0:25:32 > 0:25:35You don't smell at all, but not very exciting to look at,
0:25:35 > 0:25:39until you pass a few thousand volts through you. Watch what happens then.
0:25:39 > 0:25:42They all become much prettier.
0:25:42 > 0:25:46This is the normal neon signs that we see.
0:25:46 > 0:25:50This sign here is filled with neon gas, but when it gets excited
0:25:50 > 0:25:52with the electricity there, the electrons are leaping up,
0:25:52 > 0:25:56and as they come back down we get this fantastic red colour.
0:25:56 > 0:25:59Each element has its own unique colour
0:25:59 > 0:26:02so we can see, then, that some of these gases have uses.
0:26:02 > 0:26:04Neon is used in neon signs.
0:26:04 > 0:26:10But some of them have even more important uses, and I went to the
0:26:10 > 0:26:14University of Sheffield to have a look at one of the uses for helium.
0:26:16 > 0:26:20So what's in this little bag here that I've got then, Jim?
0:26:20 > 0:26:24What you've got in there is essentially a bag with some helium atoms,
0:26:24 > 0:26:28which are magnetically aligned or polarised.
0:26:28 > 0:26:30They are contained within the bag.
0:26:30 > 0:26:32If we were to actually image the bag, you'd see
0:26:32 > 0:26:36just the boundaries of the bag and the air space inside the bag
0:26:36 > 0:26:40filled with the gas and nothing on the outside and, similarly,
0:26:40 > 0:26:43when you breathe it in we will see the gas inside your lungs.
0:26:43 > 0:26:47The scanner is actually a giant magnet with radio detectors
0:26:47 > 0:26:51which detect the specially prepared helium atoms as they return
0:26:51 > 0:26:53to their natural state within this magnet.
0:26:53 > 0:26:59This allows Jim to build up a picture of where the gases are in my lungs.
0:26:59 > 0:27:01- Your scan is here. - Those are my lungs?
0:27:03 > 0:27:06There's your bronchus, trachea, and your two bronchi,
0:27:06 > 0:27:08main feeding bronchi coming off the bronchus.
0:27:08 > 0:27:10These are your blood vessels.
0:27:10 > 0:27:14So the amazing thing about this is that we are only seeing
0:27:14 > 0:27:17- the air inside my lungs, aren't we?- Exactly.
0:27:17 > 0:27:20You're just visualising the air spaces there.
0:27:20 > 0:27:23It's very exciting to be looking at my own lungs!
0:27:23 > 0:27:26It's nice to know they're not too bad, even though
0:27:26 > 0:27:28I know I've got a bit of a cough at the moment.
0:27:28 > 0:27:33- Nonetheless, they're reasonably healthy, you think?- They look pretty healthy.- That's all right, then.
0:27:33 > 0:27:35So this is pretty cutting-edge science here.
0:27:35 > 0:27:39We're actually using this form of helium, helium three,
0:27:39 > 0:27:42to image the workings, how our lung works.
0:27:42 > 0:27:46And actually on the screen we can see here, these are two lungs.
0:27:46 > 0:27:50This is a lung of a patient who has asthma on the left-hand side here.
0:27:50 > 0:27:52You can see some black regions.
0:27:52 > 0:27:56But after they've taken their inhaler, the lungs have opened up,
0:27:56 > 0:28:00the airways have opened up, and the helium has gone into those regions.
0:28:00 > 0:28:03We can see all the places where the air is now reaching.
0:28:03 > 0:28:06So this just shows the medicine in action.
0:28:06 > 0:28:11OK, now, it's not just helium that has exciting properties.
0:28:11 > 0:28:15If we go right the way down to the bottom of the periodic table here,
0:28:15 > 0:28:17the heavy stable element xenon,
0:28:17 > 0:28:20this has some truly remarkable properties as well.
0:28:20 > 0:28:24- We have a tank here and we've filled this with some xenon, I understand. - A little, yes.
0:28:24 > 0:28:28A little xenon so we just keep putting a little bit more in there
0:28:28 > 0:28:34and I have a very delicate, very fragile foil boat.
0:28:36 > 0:28:39I'm going to see if we can actually balance this,
0:28:39 > 0:28:44if we can float this on the xenon in this tank.
0:28:44 > 0:28:46- Try this one. - Shall we try this one first?
0:28:46 > 0:28:50Yes, we'll try our new boat. Just slide this over.
0:28:55 > 0:28:59And try our new boat.
0:28:59 > 0:29:02Ah! That's it. Look at that.
0:29:02 > 0:29:05- That really is... - APPLAUSE
0:29:05 > 0:29:08..floating on the xenon.
0:29:10 > 0:29:14There are no strings. It's a little bit fragile here.
0:29:14 > 0:29:18I think I need a volunteer to just come and very carefully help me
0:29:18 > 0:29:20add some weight into this.
0:29:20 > 0:29:25We'll have somebody from, er, the... Yes, right on the end.
0:29:25 > 0:29:28Would you like to come down? Thank you.
0:29:30 > 0:29:33OK, thank you very much. Give her a round of applause.
0:29:33 > 0:29:36If you'd like to come round here.
0:29:36 > 0:29:39I'm just trying to keep my boat level here.
0:29:39 > 0:29:43- Just add a little bit more xenon. What's your name, please?- Bethany.
0:29:43 > 0:29:44Bethany, excellent.
0:29:44 > 0:29:47Now, you are going to be probably the first person in the world
0:29:47 > 0:29:50ever to try this - we haven't even practised this.
0:29:50 > 0:29:54Have a look at this. What do you think this is? Hold it.
0:29:54 > 0:29:58- Foil.- It's foil. Does it feel like normal foil?- No.
0:29:58 > 0:30:02No, it feels strange, doesn't it? That's because it's pure solid gold.
0:30:02 > 0:30:03Right?
0:30:03 > 0:30:06This is pure solid gold so let's just screw it up a little bit
0:30:06 > 0:30:08and I'd like you to put this in here.
0:30:08 > 0:30:09Just see if you can put it in that corner.
0:30:09 > 0:30:13That corner is a little bit unstable at the moment. That's it. Oh, look at that!
0:30:13 > 0:30:16Now you have made this thing float perfectly. That's pretty amazing.
0:30:16 > 0:30:19Add some more. Will you sink it?
0:30:20 > 0:30:21Not quite. Oh, there it goes.
0:30:21 > 0:30:24Fantastic! A world first.
0:30:24 > 0:30:26Thank you very much, excellent.
0:30:26 > 0:30:31APPLAUSE
0:30:31 > 0:30:36OK, xenon is very dense and I'm very pleased that worked, but it also has
0:30:36 > 0:30:41some really remarkable properties that can be used in medicine.
0:30:41 > 0:30:44Now, while I was at the University of Sheffield,
0:30:44 > 0:30:48we took a chance to experience what it's like to breathe in
0:30:48 > 0:30:51some xenon and it has very strange effects on the body
0:30:51 > 0:30:55but it can be very useful as well, so let's just see what happens here.
0:30:55 > 0:31:00If you take a deep breath in, Peter. Breathe out.
0:31:00 > 0:31:01Deep breath in.
0:31:03 > 0:31:07Breathe out, and now breathe from the bag. OK.
0:31:07 > 0:31:10Breathe in, breathe in, breathe in, breathe in, breathe in, breathe in,
0:31:10 > 0:31:15breathe in, breathe in, breathe in, breathe in, breathe in, breathe in.
0:31:15 > 0:31:17OK, and hold your breath.
0:31:20 > 0:31:22It will be interesting if you talk as you breathe out,
0:31:22 > 0:31:25we'll see if we can hear the, er...
0:31:27 > 0:31:29- DEEP VOICE:- That's amazing. I feel really relaxed
0:31:29 > 0:31:32and I can hear that my voice has changed.
0:31:32 > 0:31:37It's gone quite deep now but I feel very happy and relaxed
0:31:37 > 0:31:39and calm. Oh, it's wearing off now.
0:31:39 > 0:31:45Wow, so that's xenon, these individual atoms of xenon,
0:31:45 > 0:31:48- interacting with my brain in some way, isn't it?- Mmm.
0:31:48 > 0:31:51So it's going into my bloodstream and interacting with my brain
0:31:51 > 0:31:54- and making me feel slightly light-headed.- Mmm.- And that's...
0:31:54 > 0:31:57At higher concentrations, that acts as an anaesthetic
0:31:57 > 0:31:59and I would just pass out, is that right?
0:31:59 > 0:32:01People do use it as an anaesthetic in a clinical setting,
0:32:01 > 0:32:04but clearly at higher concentrations than these.
0:32:04 > 0:32:07If we'd have retuned the scanner slightly, we'd have actually seen
0:32:07 > 0:32:10the xenon atoms dissolved in your blood as well.
0:32:10 > 0:32:12That's where we're going with this at the moment.
0:32:12 > 0:32:14We'd love to actually be able to pick up the xenon
0:32:14 > 0:32:17dissolved in the brain and image the xenon in the brain.
0:32:17 > 0:32:19That might give us some insight into how these
0:32:19 > 0:32:23anaesthetics are actually working in the neural system.
0:32:23 > 0:32:25- Incredible.- Yeah.
0:32:25 > 0:32:29Now, that was certainly very strange when I was breathing in this gas
0:32:29 > 0:32:33and the latest research that Jim is doing allows the individual atoms
0:32:33 > 0:32:36of xenon to be followed around the brain, even.
0:32:36 > 0:32:40Now, I'd like you to welcome three incredibly important guests
0:32:40 > 0:32:45to the RI. Would you please welcome Dave, Sarah and Riley Joyce?
0:32:45 > 0:32:49APPLAUSE
0:32:49 > 0:32:51Good to see you.
0:32:51 > 0:32:54Thank you very much. Hello. Thank you.
0:32:54 > 0:32:58Ah! He's very shy in front of the cameras here.
0:32:58 > 0:33:00I was wondering if... Could you tell me your middle name?
0:33:00 > 0:33:03What's your full name? Can you tell me your full name?
0:33:03 > 0:33:07A bit shy. He's a bit shy, but what is his full name, then, please?
0:33:07 > 0:33:11- It's Riley Xenon Joyce. - I think this is great.
0:33:11 > 0:33:14I would love to have an element for a middle name, I must say.
0:33:14 > 0:33:18So why is Riley's middle name Xenon, then?
0:33:18 > 0:33:22Well, Riley was the first baby in the world to receive xenon,
0:33:22 > 0:33:26and he received it at St Michael's in Bristol,
0:33:26 > 0:33:29due to when he was born he didn't have a pulse
0:33:29 > 0:33:33and they had to resuscitate him so he was starved of oxygen.
0:33:33 > 0:33:38This could have caused complications if he didn't get this treatment at the time,
0:33:38 > 0:33:40so this was acting as an anaesthetic.
0:33:40 > 0:33:45Would it just gently put him to sleep and allow the metabolism to slow down?
0:33:45 > 0:33:49It has given his brain time to recover and he had it alongside
0:33:49 > 0:33:53the head-cooling treatment, which works on the same principle.
0:33:53 > 0:33:56I must say that he's very shy at the moment in front of everybody
0:33:56 > 0:33:59but earlier he was running around all over the place
0:33:59 > 0:34:03- so he's clearly perfectly healthy now, isn't he? Is that right?- He is.
0:34:03 > 0:34:07In March this year he had his two-year check-up
0:34:07 > 0:34:11and he was discharged as a perfectly normal, healthy child.
0:34:11 > 0:34:15When he was born, he was given a 50% chance of having permanent brain damage
0:34:15 > 0:34:19so to come from there to where we are now is incredible.
0:34:19 > 0:34:21That is absolutely fantastic.
0:34:21 > 0:34:24So would you please thank them for coming in?
0:34:24 > 0:34:29APPLAUSE
0:34:32 > 0:34:35If we just have our periodic table up for a moment.
0:34:35 > 0:34:38Have our periodic table up.
0:34:38 > 0:34:40We've seen that we have our noble gases here.
0:34:40 > 0:34:42You're all individual atoms,
0:34:42 > 0:34:45you don't really want to combine with the others,
0:34:45 > 0:34:48but this isn't the same throughout the periodic table as a whole.
0:34:48 > 0:34:51We're trying to understand what makes some of the gases in the air so special,
0:34:51 > 0:34:54but in order to understand these, how they're bonding with each other,
0:34:54 > 0:34:58we need to look across the periodic table as a whole.
0:34:58 > 0:35:00I have a sample of one of the elements here.
0:35:00 > 0:35:03This is the element potassium. Potassium, can you stand up?
0:35:03 > 0:35:04There you are.
0:35:04 > 0:35:08So you're in this first group, the same group as lithium, sodium, potassium. Thank you.
0:35:08 > 0:35:12You're a solid, and in here we have the solid potassium.
0:35:14 > 0:35:18Potassium is a metal, and we've got this in the flask.
0:35:18 > 0:35:21At ease, periodic table. Thank you. Cards down. Very good.
0:35:21 > 0:35:28We've got a little piece of potassium here, and we've taken the air out of this flask.
0:35:30 > 0:35:34And I'm just going to gently warm the flask up.
0:35:36 > 0:35:39So potassium is a metal.
0:35:39 > 0:35:42The potassium atoms want to bond to each other
0:35:42 > 0:35:45but they don't bond to each other very tightly.
0:35:45 > 0:35:49So it is a solid, though, not a gas like our noble gases,
0:35:49 > 0:35:52but watch what happens if I just warm it up rather gently.
0:35:52 > 0:35:56Potassium is... Oh, look at that.
0:35:56 > 0:36:00What's happened here, all of the potassium atoms have separated
0:36:00 > 0:36:04from each other and given this fantastic coating over the inside.
0:36:04 > 0:36:09In fact, we've made an instant Christmas bauble, which is great!
0:36:09 > 0:36:11But this is a Christmas bauble coated with potassium,
0:36:11 > 0:36:15which is probably not so great. But anyway, very beautiful,
0:36:15 > 0:36:19but we didn't need to put a lot of energy in to pull those apart.
0:36:19 > 0:36:21How can we understand this? We're going to go back to...
0:36:21 > 0:36:23If we have the periodic table back up,
0:36:23 > 0:36:27we're going to go back to the top element in this second row.
0:36:27 > 0:36:28This is lithium,
0:36:28 > 0:36:31and we're going to move round the periodic table from lithium
0:36:31 > 0:36:33through beryllium, all the way -
0:36:33 > 0:36:36boron, carbon, nitrogen, oxygen, fluorine, neon - and see how the bonding changes.
0:36:36 > 0:36:39We have our elements lined up and bringing down electrons
0:36:39 > 0:36:41so can we have the first two lithiums, please?
0:36:41 > 0:36:44Could you come down to the front, and you're bringing some electrons with you.
0:36:44 > 0:36:46So these are our yellow electrons
0:36:46 > 0:36:48and could you put them in the energy level here, please?
0:36:48 > 0:36:50That's it, put them in there,
0:36:50 > 0:36:53and if you return to your seats, that's great. Thank you very much.
0:36:53 > 0:36:56What's happened here, as the electrons have gone into this region here,
0:36:56 > 0:37:01into these shelves here, these have pulled the atoms together
0:37:01 > 0:37:05and this is because these negatively charged electrons
0:37:05 > 0:37:07are helping pull the nuclei together
0:37:07 > 0:37:10when they're concentrated in between the two atoms here.
0:37:10 > 0:37:12Can we have our next elements?
0:37:12 > 0:37:13We have beryllium - could you come down?
0:37:13 > 0:37:16Now, on beryllium we see on the screen here the bonds are much stronger.
0:37:16 > 0:37:20Let's see why this is. We add your electron here.
0:37:20 > 0:37:22That's it, these are moving the atoms closer together,
0:37:22 > 0:37:24so even stronger still.
0:37:24 > 0:37:28So beryllium has two electrons, creates a stronger bond now.
0:37:28 > 0:37:32Lithium, beryllium. The beryllium atoms are held more tightly.
0:37:32 > 0:37:36OK, boron, on the screen here, we have three electrons.
0:37:36 > 0:37:40Can you come down please, boron? You've got one more electron here than the beryllium had
0:37:40 > 0:37:44so you're going to add your electrons. Could you add your electrons in here?
0:37:44 > 0:37:48And again, these... Oh! That really did move, that was pretty good.
0:37:48 > 0:37:50So you've a very strong bond now for the boron -
0:37:50 > 0:37:52much stronger than the beryllium. Very tightly held.
0:37:52 > 0:37:55We've got three electrons bonding these boron atoms together.
0:37:55 > 0:38:00Can we have carbons now, please? OK, and that last one.
0:38:00 > 0:38:02OK, so the atoms move closer together.
0:38:02 > 0:38:06Thank you very much, carbons. We've got some very strong bonds indeed now.
0:38:06 > 0:38:13In fact carbon there requires most of the energy of all of the elements to try and rip them apart.
0:38:13 > 0:38:16If we were trying to remove the same number of atoms apart,
0:38:16 > 0:38:18we need more energy for carbon than any other.
0:38:18 > 0:38:21This makes carbon incredibly strong.
0:38:21 > 0:38:25I have a sample of carbon here to show you and demonstrate this.
0:38:25 > 0:38:29This is a diamond, we can see this here. This is a real diamond.
0:38:29 > 0:38:31Very, very strong because of these strong bonds.
0:38:31 > 0:38:35I nearly dropped it there. But it is also incredibly hard.
0:38:35 > 0:38:40So hard, in fact, that I can actually cut this glass.
0:38:40 > 0:38:45The glass is incredibly hard, of course, but diamond is even stronger
0:38:45 > 0:38:48because of the strong bonds between the carbon atoms. So...
0:38:52 > 0:38:57It's definitely cut into the glass. In fact, it looks like it's pretty deep.
0:38:59 > 0:39:05There we are. It's cut down this crack where it's been scored with the glass there.
0:39:05 > 0:39:10So a diamond, incredibly strong, because of all these bonding electrons
0:39:10 > 0:39:12keeping the carbon atoms together.
0:39:12 > 0:39:14We've still got further to go along our periodic table.
0:39:14 > 0:39:16We've gone to carbon, we're going to keep on going.
0:39:16 > 0:39:19So nitrogens, you have five electrons in total,
0:39:19 > 0:39:23so let's see where these have to go. We've run out of room here.
0:39:23 > 0:39:26You're going to have to put your electrons in these ones
0:39:26 > 0:39:28so this is a slightly different thing going on here.
0:39:28 > 0:39:30Would you put your electrons in here? That's great.
0:39:30 > 0:39:35And these, actually, now are concentrated outside of the middle
0:39:35 > 0:39:38and these electrons are pulling the atoms further apart again.
0:39:38 > 0:39:42In fact, these do not help the bonding. These are called anti-bonding levels.
0:39:42 > 0:39:44Thank you very much, nitrogens.
0:39:44 > 0:39:47OK, we have our next element - this is oxygen.
0:39:47 > 0:39:51Let's see what happens as we keep going, adding another electron.
0:39:51 > 0:39:53Oxygens, you have to put yours in this level here,
0:39:53 > 0:39:57and again these are in these anti-bonding levels, pulling our atoms apart.
0:39:57 > 0:40:00So oxygen is a weaker bond than nitrogen.
0:40:00 > 0:40:03Let's go to our next atom. We've got two fluorines coming.
0:40:03 > 0:40:06Let's see what happens when you get together. OK. Add them in.
0:40:06 > 0:40:10That's great. Again, a very weak bond now. It's pulled further apart.
0:40:10 > 0:40:13Fluorine has one more electron, weakens the bond here
0:40:13 > 0:40:16and the fluorines are really weakly held together.
0:40:16 > 0:40:18This is the one of the reasons that makes fluorine
0:40:18 > 0:40:21so incredibly reactive. It's because of these weak bonds.
0:40:21 > 0:40:24Finally, we have our last element, neon.
0:40:24 > 0:40:27So, neon has eight outermost electrons,
0:40:27 > 0:40:29so it has one more than the fluorines had.
0:40:29 > 0:40:32Let's see where these have to go in the remaining level here.
0:40:32 > 0:40:35So if you add your electrons into these last anti-bonding levels...
0:40:35 > 0:40:38And it pulls the atoms completely apart.
0:40:38 > 0:40:40So, this means the atoms do not bond to each other.
0:40:40 > 0:40:44Thank you very much indeed for your help there. Thank you.
0:40:44 > 0:40:46APPLAUSE
0:40:48 > 0:40:51So, if we just see our periodic table again. Just have you up.
0:40:51 > 0:40:53That's great. Thank you very much.
0:40:53 > 0:40:56We're looking at these ones over here.
0:40:56 > 0:40:58We see carbon, very, very strong bonds.
0:40:58 > 0:41:01Nitrogen, not as strong as carbon, but still pretty strong.
0:41:01 > 0:41:04Fluorine, very weak bonds. Neon not bonded at all.
0:41:04 > 0:41:07But oxygen, you're just about the right strength.
0:41:07 > 0:41:10You're still reactive because the bonds aren't too incredibly strong
0:41:10 > 0:41:11between the oxygen atoms.
0:41:11 > 0:41:13Makes you very, very reactive indeed.
0:41:13 > 0:41:17Oxygen, you really are the elixir of life.
0:41:17 > 0:41:20It's you that keeps us all alive. I'm going to demonstrate this now.
0:41:20 > 0:41:23So, at ease, periodic table. Thank you.
0:41:23 > 0:41:25So, I have some breakfast cereal here.
0:41:25 > 0:41:27This is just normal breakfast cereal.
0:41:27 > 0:41:29I'm just going to put some in the bowl.
0:41:29 > 0:41:33This is just the sort of thing that you would normally do.
0:41:33 > 0:41:36But now instead of adding my milk... Oops.
0:41:36 > 0:41:41Instead of adding my milk, I'm going to add some liquid oxygen.
0:41:41 > 0:41:43So this is not the sort of thing you normally do.
0:41:43 > 0:41:45We've cooled the oxygen down. So this is oxygen gas
0:41:45 > 0:41:48that's been cooled down. It has this beautiful blue colour.
0:41:48 > 0:41:51I'm just going to pour this onto our Rice Krispies.
0:41:54 > 0:41:58OK. Now, I'm also going to add a light.
0:41:58 > 0:42:00Just put my goggles on.
0:42:00 > 0:42:03This is also something you don't normally do.
0:42:13 > 0:42:18An incredible amount of energy is released there.
0:42:18 > 0:42:22This is as the Rice Krispies, the breakfast cereal here...
0:42:22 > 0:42:27As our breakfast cereal combines with the oxygen from the air.
0:42:27 > 0:42:30And believe it or not, this is actually what happens
0:42:30 > 0:42:33inside our bodies. Not quite like this.
0:42:33 > 0:42:37We don't have flames coming out of our ears.
0:42:37 > 0:42:40But nonetheless, it is the reaction between our breakfast cereal
0:42:40 > 0:42:43and the oxygen that we're breathing in that gives us
0:42:43 > 0:42:45the energy to stay alive.
0:42:45 > 0:42:49And we have Laura here to demonstrate this.
0:42:49 > 0:42:52She's been specially trained in breathing
0:42:52 > 0:42:55with this rather delicate apparatus here.
0:42:55 > 0:42:58OK. Would you like to put this on?
0:42:58 > 0:43:00Now, what's happening here?
0:43:00 > 0:43:02Laura is breathing in. So if you breathe in...
0:43:02 > 0:43:05Breathing in normal air and it's coming in through here,
0:43:05 > 0:43:08bubbling through this solution. In the flask here,
0:43:08 > 0:43:10we have something called lime water.
0:43:10 > 0:43:13Then Laura's breathing out through this one. So the out air
0:43:13 > 0:43:14is coming out through here.
0:43:14 > 0:43:18Now, lime water reacts with carbon dioxide.
0:43:18 > 0:43:20There's very little carbon dioxide in the air,
0:43:20 > 0:43:23so there's no change taking place here.
0:43:23 > 0:43:26When lime water reacts with carbon dioxide,
0:43:26 > 0:43:30it turns cloudy due to the formation of calcium carbonate.
0:43:30 > 0:43:33No calcium carbonate forming here. But in the out...
0:43:33 > 0:43:35Well, we can begin to see already... Keep breathing. Very good.
0:43:35 > 0:43:39You're breathing beautifully there. OK. In the out, we can begin
0:43:39 > 0:43:43to see that it is going cloudy. And this is because inside Laura,
0:43:43 > 0:43:46it is the same reaction we saw taking place there.
0:43:46 > 0:43:50The breakfast cereal Laura had this morning is reacting
0:43:50 > 0:43:53with the oxygen she's breathing in. It's releasing a lot of energy
0:43:53 > 0:43:56and that's keeping her alive, but she's breathing out carbon dioxide
0:43:56 > 0:43:59that is formed during this process as the oxygen reacts
0:43:59 > 0:44:02with the fuel to produce carbon dioxide.
0:44:02 > 0:44:05Thank you very much. Give Laura a round of applause.
0:44:05 > 0:44:07APPLAUSE
0:44:11 > 0:44:16So, oxygen is incredibly important just to stay alive.
0:44:16 > 0:44:22But we've seen that there's only 21% of oxygen in the air.
0:44:22 > 0:44:26So, wouldn't it be better if there was much more oxygen in the air?
0:44:26 > 0:44:28Well, probably not.
0:44:28 > 0:44:32I'm going to demonstrate this now with the help of my volunteer here,
0:44:32 > 0:44:36sausage man. OK. Now, sausage man is made of the same sort of things
0:44:36 > 0:44:39that I'm made up of. He's made up of meat, of course.
0:44:39 > 0:44:42And I'm just going... We've connected him to a heating wire.
0:44:42 > 0:44:45I'm just going to turn up this heating wire here. So, there we are.
0:44:45 > 0:44:47The heating wire is just...
0:44:47 > 0:44:50Just turn it on a very low voltage there.
0:44:50 > 0:44:52It's just beginning to heat up.
0:44:52 > 0:44:55Now, it's not really causing too much of a problem.
0:44:55 > 0:44:59But watch what happens if I increase the amount of oxygen in the air.
0:44:59 > 0:45:02Again, we're going to use the liquid oxygen to do this.
0:45:02 > 0:45:07It's just to provide a lot of oxygen gas in the environment.
0:45:07 > 0:45:10So he's just with the heating coil there.
0:45:10 > 0:45:13Is anything beginning to happen?
0:45:13 > 0:45:16His leg's smoking a bit as the wire's heating.
0:45:16 > 0:45:19So this is like you're on a different planet
0:45:19 > 0:45:22and there's a lot of oxygen on the planet here.
0:45:22 > 0:45:25You accidentally lean against a cooker...
0:45:25 > 0:45:27And look what's happening here.
0:45:28 > 0:45:31Poor sausage man is now in flames.
0:45:34 > 0:45:39He's gone up rather drastically here.
0:45:39 > 0:45:44This is because of the increased oxygen in his environment.
0:45:44 > 0:45:46So, yes, of course, we do need oxygen to stay alive.
0:45:46 > 0:45:48It does provide us with our energy.
0:45:48 > 0:45:53But too much would definitely be a bad thing.
0:45:53 > 0:45:56I need to put out our sausage man. I think it might be very difficult
0:45:56 > 0:45:59to put him out since there's so much oxygen in there.
0:45:59 > 0:46:02Let's try... We've got some tomato ketchup here.
0:46:02 > 0:46:05LAUGHTER
0:46:05 > 0:46:06It's...
0:46:08 > 0:46:09Wow.
0:46:13 > 0:46:18It leaks as well. Great. Somebody didn't put the top on properly.
0:46:18 > 0:46:19There we are. We've put him out.
0:46:22 > 0:46:25Oops. What a mess. OK.
0:46:25 > 0:46:27OK. So, you get the idea
0:46:27 > 0:46:32that too much oxygen would certainly be bad for us.
0:46:32 > 0:46:36But on a serious note, it's incredibly difficult to put out
0:46:36 > 0:46:37a forest fire.
0:46:37 > 0:46:40These are incredibly difficult to put out, even with just 21% oxygen.
0:46:40 > 0:46:44If it was 100% oxygen, there would be no chance.
0:46:44 > 0:46:48So 21% of the air is made up of oxygen.
0:46:48 > 0:46:50This is how much we need to breathe.
0:46:50 > 0:46:54But what happens if you reduce the amount? Can we still stay alive?
0:46:54 > 0:46:56Well, I went to a place just outside Cambridge
0:46:56 > 0:46:59where they've reduced the amount of oxygen in their rooms there
0:46:59 > 0:47:02from 21% down to 15%.
0:47:02 > 0:47:05And they say that things just can't burn in this environment.
0:47:05 > 0:47:08- Well, let's see what happened. Can I have a fire?- Yes.
0:47:08 > 0:47:11- Can I set fire to your newspaper? - I've got a newspaper here
0:47:11 > 0:47:15- and you try to light my newspaper. - OK.- All right.
0:47:16 > 0:47:20- See if it works.- Shall I use a lighter?- Use the lighter.
0:47:20 > 0:47:23I'll try the lighter first of all. OK.
0:47:26 > 0:47:29- Oh. Empty?- I don't think it's a very good one.
0:47:29 > 0:47:34- Try mine if yours is empty. - This is a new one, is it?
0:47:34 > 0:47:38- OK.- OK. Doesn't work.- Matches. - Matches. OK.
0:47:38 > 0:47:40Ah! This is better.
0:47:40 > 0:47:41OK. Try again.
0:47:43 > 0:47:45Of course, the matches are still lighting
0:47:45 > 0:47:47because they have their own oxygen built in here.
0:47:47 > 0:47:50That's what's allowing them to strike,
0:47:50 > 0:47:54but there's not enough oxygen to allow your newspaper
0:47:54 > 0:47:56or the match to actually burn.
0:47:56 > 0:48:00- It's only the match head with oxygen there.- Absolutely correct.
0:48:00 > 0:48:03The newspaper could not burn by itself. Impossible.
0:48:03 > 0:48:06Of course, we can breathe fine in here. It doesn't affect us.
0:48:06 > 0:48:09It doesn't affect us at all. We could live in here for ever.
0:48:09 > 0:48:10Very impressive.
0:48:15 > 0:48:19We've come outside to try a slightly larger-scale version of the lighter.
0:48:19 > 0:48:24The lighter couldn't start a fire in the room because it didn't bring
0:48:24 > 0:48:28any oxygen with it and there wasn't enough oxygen in the room itself.
0:48:28 > 0:48:30So this should... This is petrol.
0:48:30 > 0:48:32I've soaked this torch here in petrol.
0:48:32 > 0:48:34It should light nice and easily.
0:48:34 > 0:48:39Yes. Look at that. So, this is burning rather well.
0:48:39 > 0:48:42The question is, will this go out in the room?
0:48:43 > 0:48:45Well, let's find out.
0:48:58 > 0:49:01And the fire has instantly gone out.
0:49:01 > 0:49:06There really just isn't enough oxygen in this room to allow this,
0:49:06 > 0:49:09my torch here, to carry on burning.
0:49:09 > 0:49:12But there is enough for me to carry on living.
0:49:12 > 0:49:14So that's pretty good and I'm happy.
0:49:16 > 0:49:20So, this fire prevention system works by decreasing
0:49:20 > 0:49:24the amount of oxygen and increasing the amount of nitrogen.
0:49:24 > 0:49:27Nitrogen is a very important component of the air
0:49:27 > 0:49:31because it's so inert, because of these very strong bonds.
0:49:31 > 0:49:34So we're now going to look at some of the properties
0:49:34 > 0:49:36of this inert gas, nitrogen.
0:49:36 > 0:49:40And this is one of the components in many explosives
0:49:40 > 0:49:42such as this nitroglycerin here.
0:49:42 > 0:49:45This is a very dangerous explosive.
0:49:45 > 0:49:49In fact, Alfred Nobel...
0:49:49 > 0:49:56earned his money in trying to work out how to make this more stable.
0:49:56 > 0:49:59I need to put on some special kit here, some protective clothing
0:49:59 > 0:50:02and some ear protectors. OK.
0:50:04 > 0:50:08And I'm going to add a drop of nitroglycerin to the filter paper.
0:50:12 > 0:50:16Now then. Adding a drop of nitroglycerin.
0:50:16 > 0:50:18There we are. That's it.
0:50:22 > 0:50:28And I think I'll just remove this nitroglycerin from here.
0:50:28 > 0:50:30I don't want to be too close when this goes off.
0:50:31 > 0:50:35So I'll hand this to Mark. Thank you. Right.
0:50:35 > 0:50:38Now, the nitroglycerin contains a lot of nitrogen locked up
0:50:38 > 0:50:42into its chemical composition.
0:50:42 > 0:50:47And it's the sudden release of this that gives it its explosive power.
0:50:48 > 0:50:51BANG!
0:51:04 > 0:51:06That really was quite violent,
0:51:06 > 0:51:09the sudden release of that nitrogen gas.
0:51:09 > 0:51:12And that's what makes an explosive explosive.
0:51:12 > 0:51:15Most of them contain nitrogen built in.
0:51:15 > 0:51:19But remarkably, this reaction, this explosive release of nitrogen gas,
0:51:19 > 0:51:23has been used to save thousands of lives.
0:51:23 > 0:51:25For this, I need a car.
0:51:25 > 0:51:28Have you got a car there, please, Chris?
0:51:28 > 0:51:31OK. Well, it's not exactly a real car.
0:51:31 > 0:51:35But it is a real steering wheel. OK.
0:51:35 > 0:51:38So, this contains a compound with nitrogen in it.
0:51:38 > 0:51:40It's nitrogen combined with sodium.
0:51:40 > 0:51:43Can we have our periodic table up for a second, please?
0:51:43 > 0:51:47So, we have nitrogen over here combined with sodium over here.
0:51:47 > 0:51:50But it's the formation of our very, very strong
0:51:50 > 0:51:55nitrogen-nitrogen bonds that leads to the rapid inflation
0:51:55 > 0:51:56of this air bag.
0:51:56 > 0:52:00Now, I need a volunteer from the audience for this, please.
0:52:00 > 0:52:03Er, who shall we have? Yes, would you like to come down the front?
0:52:03 > 0:52:05Thank you very much. Would you like to stand all the way over here?
0:52:05 > 0:52:08- And your name is...? - Fred.- Fred. OK, Fred.
0:52:08 > 0:52:10Now, you are going to trigger this air bag.
0:52:10 > 0:52:13So if I just take this from Chris. Is this primed?
0:52:13 > 0:52:16Just going to make sure it's all OK to trigger.
0:52:20 > 0:52:23OK. Thank you very much. Now, if you stand over here.
0:52:23 > 0:52:25He's very keen to get a hand on the trigger here.
0:52:25 > 0:52:28Now, we're going to count down from three. OK. If you hold this.
0:52:28 > 0:52:31Don't press the button yet. OK. Now, when we've counted down,
0:52:31 > 0:52:32I want you to press the button.
0:52:32 > 0:52:35But don't blink. If you blink, you'll miss this.
0:52:35 > 0:52:39It's a very quick reaction. OK. So, three, two, one.
0:52:39 > 0:52:42- BANG! - There we are.
0:52:42 > 0:52:45OK. Thank you very much indeed. A round of applause for Fred.
0:52:45 > 0:52:47APPLAUSE
0:52:47 > 0:52:51So, this air bag works here
0:52:51 > 0:52:55because the nitrogen really wants to bond to itself to form
0:52:55 > 0:52:59these nitrogen molecules and it's this explosive release of nitrogen
0:52:59 > 0:53:04that inflates the air bag so quickly. We can see this here
0:53:04 > 0:53:08in slow motion. Actually, when the crash test dummy hits the bag,
0:53:08 > 0:53:12this bag is actually deflating. The air is coming out of this.
0:53:12 > 0:53:15But it needs to be released so quickly,
0:53:15 > 0:53:18that's why an explosive is needed.
0:53:18 > 0:53:20So nitrogen here saving lives.
0:53:20 > 0:53:23But actually, nitrogen is vital for life.
0:53:23 > 0:53:25We couldn't live without it.
0:53:25 > 0:53:30Every protein in every cell in our body is made up of amino acids.
0:53:30 > 0:53:34And every one of these amino acids contains nitrogen.
0:53:34 > 0:53:36So somehow we need to take the nitrogen from the air
0:53:36 > 0:53:40and get it to combine with other elements so we can form compounds
0:53:40 > 0:53:41that are useful to us.
0:53:41 > 0:53:44Now, plants have learnt how to do this over millions of years,
0:53:44 > 0:53:47but it took chemists a long time to do this.
0:53:47 > 0:53:51And the first way this was achieved was by emulating nature...
0:53:51 > 0:53:53- THUNDER - ..a process in nature
0:53:53 > 0:53:56where nitrogen and oxygen are beginning to react.
0:53:56 > 0:53:58During this electrical storm,
0:53:58 > 0:54:02the lightning here is providing sufficient energy to split apart
0:54:02 > 0:54:06these molecules and this can allow nitrogen and oxygen to recombine.
0:54:06 > 0:54:10We're going to try and do this in the lecture now. And I have...
0:54:10 > 0:54:13Well, this is what every mad scientist should have.
0:54:13 > 0:54:16It's a Jacob's ladder and here we see it switched on.
0:54:16 > 0:54:19So what we're doing here is passing thousands of volts
0:54:19 > 0:54:23between these two electrodes and this is causing the molecules
0:54:23 > 0:54:27in the air to be ripped apart, ripping their electrons out.
0:54:27 > 0:54:29This heats up the air just above it,
0:54:29 > 0:54:32making it easier to pass the electric current through that,
0:54:32 > 0:54:34which is why this thing is gradually rising.
0:54:34 > 0:54:39But how will we know if there is any chemical reaction taking place here?
0:54:39 > 0:54:42Well, we're going to keep an eye on this
0:54:42 > 0:54:45and look for signs of a reaction. We should see a colour change.
0:54:45 > 0:54:48Now, I can demonstrate the colour change that we're going to see.
0:54:48 > 0:54:50I have two flasks here.
0:54:50 > 0:54:53This contains a compound called nitric oxide.
0:54:53 > 0:54:55This is just air.
0:54:55 > 0:54:58But when the two come together...
0:54:59 > 0:55:00..we form...
0:55:03 > 0:55:07..a new compound that we can see, that isn't colourless.
0:55:07 > 0:55:12There we are. And this is the gas nitrogen dioxide.
0:55:12 > 0:55:16So, this is what we're looking for in our Jacob's ladder.
0:55:16 > 0:55:19So the nitrogen, if it combines with the oxygen,
0:55:19 > 0:55:24we may be able to see this coloured gas nitrogen dioxide.
0:55:24 > 0:55:28We'll keep an eye on the tube there. It just contains air.
0:55:28 > 0:55:31I'll just get rid of that.
0:55:31 > 0:55:35But this isn't really real lightning.
0:55:35 > 0:55:38This is only a very small spark here.
0:55:38 > 0:55:41We can maybe begin to see hints of some colour change,
0:55:41 > 0:55:44but we'll keep an eye on it. We need a bigger spark.
0:55:44 > 0:55:47We need something to produce about a million volts.
0:55:47 > 0:55:50And this is what this is for.
0:55:50 > 0:55:52This is a Tesla coil
0:55:52 > 0:55:56and it can generate a million volts.
0:55:56 > 0:55:58We've had some problems with this bit of kit.
0:55:58 > 0:56:02It basically fries all the cameras, all the electrics, all the lights.
0:56:02 > 0:56:07So this really should give us some rather impressive lightning.
0:56:07 > 0:56:11Now, I must ask everyone just to remain in your seats
0:56:11 > 0:56:13for this demonstration. Let's see how we go.
0:56:18 > 0:56:20BUZZING
0:56:48 > 0:56:51Phew.
0:56:51 > 0:56:53CHEERING AND APPLAUSE
0:56:59 > 0:57:02That really... That really is quite nerve-racking, I must say.
0:57:02 > 0:57:05And what we are seeing here with all that energy
0:57:05 > 0:57:08was causing the nitrogen molecules and the oxygen molecules
0:57:08 > 0:57:10to be ripped apart and then they recombine
0:57:10 > 0:57:14to form nitrogen dioxide and that's what we can see,
0:57:14 > 0:57:16this brown colour here now in our Jacob's ladder.
0:57:16 > 0:57:19And we can also form molecules of ozone.
0:57:19 > 0:57:23That's three oxygen atoms together. So, what have we learnt here?
0:57:23 > 0:57:27We've learnt that the air is more complicated than we ever thought.
0:57:27 > 0:57:30The alchemists thought it was made up of just one element
0:57:30 > 0:57:33but they were wrong. It's made up of a number of different elements,
0:57:33 > 0:57:37of nitrogen, oxygen. We've seen how important they are to our lives.
0:57:37 > 0:57:40Without the oxygen, we'd all be dead.
0:57:40 > 0:57:42But with too much, we couldn't survive either.
0:57:42 > 0:57:46We've also seen how the very rare gases, the noble gases, can be used
0:57:46 > 0:57:48to save lives in hospitals.
0:57:48 > 0:57:53Now, the alchemists spent their lives trying to master the elements.
0:57:53 > 0:57:55But they only scratched the surface.
0:57:55 > 0:57:57They might have been able to play with fire,
0:57:57 > 0:58:00but they couldn't control it or understand what it was made of.
0:58:00 > 0:58:04Nor could they pick out the elements from the air and use them
0:58:04 > 0:58:06to make the world a better place.
0:58:06 > 0:58:09This is where the modern alchemist takes over.
0:58:09 > 0:58:13Join us in the next lecture where we'll investigate
0:58:13 > 0:58:15how a glass of water contains the remnants
0:58:15 > 0:58:18of the most violent reactions in the world.
0:58:18 > 0:58:19Good night. Thank you.
0:58:23 > 0:58:26Subtitles by Red Bee Media Ltd