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00:30Hello, thank you, and welcome to Think of a Number.
00:35Now, first, think of a number.
00:37Think of the number of senses you've got.
00:38If you know the answer, put your hand up.
00:41Five.
00:42Five! Of course you have.
00:44And we use our senses to detect things.
00:47And some of you have got files with peculiar substances.
00:52Now, we're going to find out what it is.
00:53And what I want you to do...
00:54I know what it is, you see.
00:55I'm going to use my senses to detect it.
00:57And I want you to do exactly as I do, and you won't go far wrong.
01:01Right?
01:03Look at it.
01:07Open it.
01:11Don't smell of anything.
01:12Stick your finger in.
01:25What's wrong? What have you done?
01:27Oh, you haven't tasted it?
01:29No, no, no, no.
01:31I said, watch me and do what I do.
01:33And I stuck that finger in, but I tasted that one.
01:39Because, because I know it tastes awful, doesn't it?
01:44You've all got sweets, I think, haven't you?
01:46Yes.
01:47Suck your sweets, it'll get rid of the taste.
01:48That's all right.
01:48What it is, it's a mixture of alum and bitter aloes.
01:52And it tastes terrible.
01:54And it's made with several chemical processes.
01:57Well, that's not unusual.
01:58Chemical processes are happening all the time.
02:00While you're watching, your body is performing all kinds of chemical processes.
02:04Because your body is made of chemicals.
02:07And so is everything else around us.
02:08And that's what this programme is all about.
02:11The building blocks of nature.
02:12The elements.
02:17There are 105 elements.
02:1993 natural and the rest man-made.
02:22And I should really tell you what they all are.
02:24Shall I?
02:26Yes.
02:27All right, here we go.
02:29There's antimony, arsenic, aluminum, senilium, hydrogen, oxygen, nitrogen, rhenium, nickel, neodymium, neptunium, germanium, iron, americium, ruthenium, uranium, europium, zirconium, luteum,
02:38ethium, vanadium, lanthemum, osmium, astatine, radium, gold, proctatinium, indium, gallium, iodine, thorium, thulium, and phallium.
02:45There's yttrium, yterbium, and actium, rubidium, boron, gadolidium, niobium, iridium, strontium, silicon, silver, cimmerium, bismuth, bromine, lithium, beryllium, and barium.
02:56There's rutherfordium and harnium.
02:58And so far, there's only half of them.
03:00There's homium and helium and hafmium and ermium and phosphorus, franzine, fluorine, termium, manganese, mercury, molybdenum, magnesium, dysprosium, scantium, cymbalium,
03:08cesium.
03:09There's lead, praterinium, platinum, plutonium, palladium, promethium, potassium, polonium, tantulum, ethium, titanium, tellurium, cadmium and calcium and chromium and curium.
03:20There's sulfur californium, fernium, bacchelium, lorencium, mendelium, einsteinium, nobelium, and argon, krypton, neon, radium, xenon, zinc and rhodium, and chlorine, carbon, cobalt, copper, tugs, and tin, and sodium.
03:28Dun, dun, dun, dun, dun, dun, dun, dun, dun, dun, but how can you sort them all out, 105 elements?
03:40Well, at first, scientists sorted them out in weight order.
03:43The lightest first, hydrogen, then helium, and all the way through to the heaviest.
03:48And then, in 1869, a Russian chemist called Mendeleev, he wrote them all down on cards, and he played a sort of patience game.
03:58And he laid them out so they were all in columns.
04:01So all the similar elements were all in the same column.
04:05And he produced this periodic table.
04:09Now, there were holes in it all over the place.
04:11And people said, well, that can't be right.
04:12You've left holes.
04:13And he said, ah, someday somebody is going to discover the elements that fit the holes.
04:20And he was absolutely right.
04:23But in 1869, we couldn't analyse an atom.
04:26We didn't know what it was made of.
04:28So how could he have been right?
04:29Well, it's always been a puzzle to everyone.
04:31And yet, now that we can analyse atoms, we see that Mendeleev was absolutely correct.
04:39And we can show you that by looking at models of the first 18 atoms.
04:43Take a bow, atoms!
04:46And there they all are, with oxygen there.
04:49Thanks, oxygen.
04:50The rest of you can look up, and we'll have a look at oxygen now.
04:54If you look, there are these pink balls.
04:57These are electrons.
04:59And electrons whiz round in orbits.
05:00And oxygen is number eight in the periodic table.
05:04And amazingly, one, two, three, four, five, six, seven, eight electrons.
05:09If you look at the nucleus of the atom, you see one, two, three, four, five, six, seven, eight protons.
05:16Now, these black ones are called neutrons.
05:19And there happen to be eight as well in oxygen.
05:22But this isn't always the case.
05:23And that determines the weight of the individual elements.
05:26However, if you meet an atom and it's got eight electrons and eight protons, it must be an oxygen atom.
05:34If you meet an element that's got six electrons and six protons, it must be carbon.
05:40Now, you don't meet single atoms walking down the street, do you?
05:42Atoms are always grouped into lumps of things.
05:45Or they've combined with other things to make all kinds of compounds.
05:49Now, how do elements combine?
05:52Well, let's try and show you.
05:55You're chlorine, aren't you?
05:56Come out, chlorine.
05:58Thank you very much.
05:58And your sodium, there.
06:02Can you come out?
06:03If you stand there, chlorine.
06:06Is that comfortable?
06:07Good.
06:08And sodium, you come and stand there.
06:10Wait there, I won't be long.
06:11Now, this is sodium, number 11 in the periodic table.
06:14Take a bow.
06:15And we can see...
06:16Oh, your hat came off.
06:17We can see there are 11 electrons.
06:20Two in this inner orbit here.
06:22And there are never more than two in the inner orbit.
06:24And then there's a secondary orbit with one, two, three, four, five, six, seven, eight electrons.
06:30And there are never more than eight in the secondary orbit.
06:33But that's only ten.
06:34You've got an extra electron.
06:35And there it is, whizzing round in its own orbit.
06:39And it's that single electron that gives you your characteristics.
06:42Makes you different from all the rest.
06:44Do you understand?
06:45Wait there.
06:46This is chlorine.
06:48It's a nice name, chlorine, isn't it?
06:50It's a bit like Doreen, isn't it?
06:52What's your surname?
06:53What's your last name?
06:53I think, sir.
06:54Robinson.
06:55Chlorine Robinson.
06:57OK.
06:58You're number 17 in the table.
07:00And if we count the electrons, there are 17.
07:01Two in the inner orbit.
07:03Eight in the next orbit.
07:04And then, one, two, three, four, five, six, seven in the third orbit.
07:09Now, were there eight in this outer orbit, that would be full as well.
07:13So you've got one space.
07:15You see?
07:16Now, elements like things neat and tidy.
07:19You like to fill that space, you see.
07:22So you could do with an extra electron.
07:24Here comes sodium.
07:27Here comes sodium.
07:27He's got an extra electron.
07:29So if you lent it to her, you'd have two complete orbits, and you'd be happier.
07:33So they come together like this.
07:36And he gives her an extra electron.
07:41And now, they're bonded together.
07:45No longer sodium and chlorine, although their centres are exactly the same, the nucleus.
07:51But now, they're bonded, and they are formed and produced sodium chloride.
07:57And do you know what sodium chloride is?
08:00Pure salt.
08:01A very stable compound.
08:02So now, you're the salt of the earth.
08:04And I hope you'll both be very happy together.
08:05Okay.
08:07Give me a round of applause.
08:08They're going on honeymoon.
08:09No, no.
08:11We can't split you up now.
08:13You'll have to sit together.
08:13Can you come and sit in her chair over there?
08:16And come on, chlorine.
08:18And you sit with sodium here.
08:19Right?
08:20You can hold hands if you like.
08:25Some elements, naturally, are formed into a very neat arrangement.
08:29They don't have extra electrons whipping around on their own.
08:33And they are the inert gases, like helium, neon, argon, and krypton.
08:39And these are very unusual.
08:41Take neon.
08:41If you apply an electric charge to neon, the electrons tend to fly off.
08:48But they don't actually fly off.
08:49As though they were held on springs, they spring back into position.
08:52And as they fly back into position, they produce light.
08:59And you get neon light.
09:01It's on the blink.
09:03Now, some elements, especially the ones towards the other end of the table,
09:07with lots of electrons, are very unstable.
09:10And the electrons and the protons and neutrons tend to break off.
09:14And these are your radioactive elements.
09:19This is a radiation detector, rather like a Geiger counter.
09:30And this, in this bottle, is uranium salt, which is radioactive.
09:41Now, I'm not daft.
09:45That radiation from that uranium salt is very mild.
09:51It's less radiation than you get from a luminous watch.
09:54But we've even got radiation coming from our own bodies,
09:56because we have phosphorus in our bodies, which is radioactive.
09:59And the study of the elements is chemistry.
10:03So, I'll just pop down to the chemist's shop.
10:05In here, in this globe, there is a rose.
10:19Now, I'm going to apply some gas to the rose.
10:22And this is chlorine.
10:23It's you, chlorine.
10:24Yes?
10:25Yes.
10:25And here it comes.
10:26You can see it's bubbling through this water.
10:31I'll leave that for a while.
10:33And see, in a moment, what it does to the rose.
10:36However, have a look at some more of these elements.
10:39Here are some of the more common ones.
10:42Oxygen, nitrogen, silicon, and aluminium.
10:44Did you know that in a spade full of garden earth,
10:47you'll have 75% silicon and 25% aluminium, or almost?
10:51But you can't get the aluminium out.
10:53It's very difficult.
10:54Now, next to aluminium, we've got gallium.
10:58Now, if you can make pans out of aluminium,
11:00why can't you make them out of gallium?
11:01Well, here is a gallium spoon.
11:04What's wrong with that?
11:06It's a bit dull.
11:08But look.
11:11It's a Urigella spoon.
11:14It bends.
11:15And that's because gallium melts at body temperature.
11:22And just by holding it in my hand,
11:25it's starting to break up and melt.
11:28It's very thin.
11:29But if I squeeze it,
11:32you may actually see drops of gallium forming.
11:42It's forming apart.
11:43It's as much use as a chocolate teapot.
11:48And can you see?
11:49There we are.
11:50Little drops of gallium.
11:53Looks like mercury.
11:54Now, if you stir a hot drink with it,
11:56look what happens.
11:58It just melts.
12:02So gallium would be no use to make anything solidly.
12:06It looks just like mercury.
12:08Just wipe my hand.
12:09Now, have a look at mercury in the table.
12:15Here it is.
12:16Next to gold.
12:19And scientists have bombarded mercury
12:21and knocked an electron and a proton off mercury
12:25and produced gold.
12:27It's something the alchemists have tried to do for centuries.
12:30The trouble is, it costs so much
12:31that it's cheaper to dig up the gold.
12:33Now, these elements in the middle
12:37are your earth elements.
12:39Things like nickel, copper, iron.
12:42The things you find in the ground.
12:44But you can't find all elements
12:45just lying around
12:47because they just wouldn't last long.
12:49Take this one.
12:51This is sodium.
12:53It's you, sodium.
12:55Here it is.
12:56Sort of a silvery substance.
12:59And it's kept in liquid paraffin.
13:05That's because it reacts with moisture.
13:07So it's got to be kept away from water.
13:10And as you know, there's moisture in the air.
13:12And we'll show you how it reacts
13:13by putting it in water.
13:29Here we are.
13:30With a bang and a smoke ring.
13:32And it's completely disappeared.
13:34Now that's sodium.
13:37There are other elements
13:38that have the reverse effect.
13:42This is phosphorus
13:43and it has to be kept in water
13:44because if you take it out of the water,
13:47well, let's cut a sliver
13:50and perhaps you'll see.
14:03Does anybody know what phosphorus is used for?
14:07Anyone?
14:08Matches.
14:10Making matches.
14:12I know everything these days.
14:14It's starting to smoke.
14:20As it comes into contact with the air.
14:26And there it goes.
14:28It burns in air.
14:30So it has to be kept in water.
14:31Can you still see me?
14:55Look at the rose.
14:56Look what's happened to the rose.
14:57It's going pale.
15:01It's being bleached
15:02because chlorine is a bleach.
15:05Now, how did the elements occur?
15:09They were all made millions and millions of years ago
15:11when the earth was a very violent place.
15:14Perhaps as violent as this.
15:16The violence that you see when you look at the sun
15:33is created by the conditions at the very centre of the sun.
15:37The temperature is 20 million degrees.
15:40And the pressure, about half a billion tonnes a square inch.
15:45And under those conditions, hydrogen atoms are thrown together
15:49and they fuse to form helium atoms.
15:52As they do that, they give off incredible amounts of energy.
15:56And that energy creates this,
16:00but also radiates over 93 million miles
16:04and gives us on earth all our energy.
16:08Absolutely all of it.
16:09Now, when the sun gets hotter,
16:12the helium atoms will start to collide
16:13to form all the other elements.
16:16And that is how all the elements are formed.
16:19For instance,
16:20if three helium atoms come together
16:22in a split second of time,
16:24just a millionth of a millionth of a second,
16:26those three helium atoms would produce this.
16:30Do you know what it is?
16:39Burnt toast.
16:41Burnt toast.
16:42Hang on, it's...
16:42It's all got sticky.
16:45Here you are.
16:46But it's not burnt toast.
16:47Do you know what it really is?
16:49Carbon.
16:50Carbon.
16:51Yes.
16:52You know, I have the tray.
16:55Yes.
16:56Because bread is carbohydrate.
16:58Carbon, hydrogen and oxygen.
17:00Hydrogen and oxygen make water.
17:02So when you heat the bread,
17:03you drive off the water
17:04and you're left with carbon.
17:06And everything that burns,
17:08anything that burns and turns black
17:10has got carbon in it.
17:12Now, carbon combines with itself
17:14and lots of other things
17:15and makes an enormous amount of products
17:18as long as you have
17:20your carbon-based raw materials.
17:25Like coal and oil.
17:28Now, coal used to be used to make gas.
17:31But now we get natural gas.
17:33However, as they made the coal-inty gas,
17:34they got a nasty, sticky, black substance
17:36left at the bottom of the equipment.
17:39And they used to throw it away
17:40until they found out it was coal tar.
17:42And coal tar now,
17:43apart from how we're to make asphalt,
17:45is also used to make aspirin, detergents,
17:48soaps and all kinds of things like that.
17:50Coal-based products make film,
17:52make scents, perfumes, aftershaves
17:54and all those things.
17:55Make mothballs and TNT.
17:56Did you know that mothballs and TNT
17:58are very similar?
17:59Makes all kinds of plastics.
18:01And your oil-based products,
18:03well, as you know,
18:03we all get petrol and lubricating oil,
18:06but we also get nylon from oil.
18:08And we also get polyurethane
18:10and all the vinyls and all the paints.
18:12And we also get propylene.
18:14And all kinds of plastic products.
18:17Synthetic rubbers.
18:18And we also get bubble gum.
18:21All from oil-based products.
18:22And we get potato.
18:24Potatoes.
18:25Well, potatoes are your natural carbons.
18:28Carbohydrates.
18:29Potatoes, sugars, lots of foods.
18:31And things like cottons.
18:32And silk.
18:33And beeswax.
18:34And diamonds.
18:35Did you know that diamonds are pure carbon?
18:39From coal-based products,
18:41we get at least a thousand other products.
18:45And from an oil-based,
18:46we get over 2,000 other products.
18:48So, you see, to carry on our lives normally,
18:51we need all these raw materials,
18:54like oil and coal.
18:56Now, Great Britain is the fifth largest producer
18:59of oil in the world.
19:00But our oil reserves are going to run out sooner or later.
19:04However, our coal resources can last at least 300 years.
19:08But to get it out of the ground,
19:10today, you need a very sophisticated pick and shovel.
19:13We'll see you next time.
19:26This is the most sophisticated coal cutting machine in the world.
19:49It cuts the coal with these sharp edges here.
19:53Now this is a model, and it's an actual size model, and these are made of wood.
19:58But the real cutting edges are made from tungsten carbide, which is another carbon-based product which is almost as hard as diamond itself.
20:07Now, this machine, when it's going this way, cuts from this end, but it's also got another cutting edge eight metres away down here.
20:16The coal face would be here, and it would traverse that way, and then that way, cutting away at the coal.
20:27These teeth, as they cut the coal, break it up into small bits and channel it down there onto a conveyor belt, which takes it away.
20:36But as I said, it's very sophisticated.
20:39It actually sucks in a lot of the dust, so that it's quite a clean running machine.
20:44It weighs 26 tonnes, and it's powered by a 500-horsepower electric motor, and the power comes in here.
20:55There are 900 or so machines similar to this working in Britain.
20:59But this one is very sophisticated because of this.
21:03It's a coal thickness probe.
21:07What it does is analyses the natural radiation in the strata.
21:14Similar radiation that you get off a watch or from uranium assault.
21:20It's set now to cut the coal face away, leaving five inches of coal,
21:26because the edges of the coal face are usually part coal and part rock,
21:30and it's poor quality coal, and we only want the best quality.
21:34Now, this machine, in one day, can cut enough coal to cover a football pitch to the depth of six feet.
21:42And in a year, just one machine like this can cut a million tonnes of coal.
21:47So, with machines like this, we're not liable to run short of our coal to produce our coal-based carbon products.
21:58So, let's have a carbon-based trick.
22:00I've got five dice here, but they look a bit different to dice.
22:03They're formed in the shape of carbon rings,
22:07because carbon with hydrogen forms benzene when it's in the shape of a ring.
22:10So, if you hold that end, and you hold that end,
22:13and you whiz those around, and then put it down here again, right?
22:17And then I want you to cover it, cover the top with this piece of paper, right?
22:22And you'll have those faces facing you.
22:24And you said you were good with a calculator before, didn't you?
22:27So, I want you to feed the five numbers into your calculator.
22:30So, that's one, plus the next one, plus the next one.
22:33When you get to the end, don't press the equal sign.
22:35OK? So, you know where to put that on the top.
22:37Right? Wait till I turn me back and give them another spin.
22:41Then I don't know the numbers. Give them a spin!
22:46And start feeding those numbers that are facing you into the calculator.
23:00Are they in now?
23:01All right, don't press the equal sign.
23:03Now, I'll come round quickly and look.
23:07When you press the equal sign, the number will be 3019.
23:13Press it.
23:153019!
23:16Ah!
23:20It was a trick, wasn't it?
23:21Of course it was a trick.
23:22If you'd like to know how to do the trick, drop me a line.
23:24You don't have to make a machine like this.
23:26You can write the numbers down on paper.
23:27If you'd like to know about carbon-based products,
23:29coal mining, drop us a line.
23:31Johnny Ball, think of a number, BBC Television, London, W1A 1AA.
23:37But remember, thanks to the resources of coal that we have in the ground,
23:41we've enough carbon to produce in the future all our carbon-based products.
23:46And that suits me fine.
23:48APPLAUSE
23:50Bye!
23:52APPLAUSE
23:53Thank you very much.
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