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TVTranscript
00:30Hello. Thank you very much.
00:35Cease. Thank you and welcome to Think of a Number.
00:38And thanks for that incredible applause.
00:40Whatever made you applaud like that?
00:42Because it's much too much, you see, and I haven't done anything yet.
00:46So what I'll do is I'll go out again and just give me half that applause.
00:50Just about half that much.
00:51And we'll see how that goes.
00:52All right. Hang on.
00:54Ready? Go!
01:01No, that's worse.
01:02I'll tell you what we'll do.
01:03This time, applaud the same speed as you did the first time.
01:06But I only need half of it.
01:07So I know.
01:08Just applaud with one hand.
01:09Ready? Go!
01:13Marvellous.
01:14That's lovely.
01:15Sounds like absolutely nothing.
01:16And that's what this programme is all about.
01:19Absolutely nothing.
01:20But first, I'm going to influence your minds.
01:24Think of a number, any number you like, but don't think of 362.
01:31It's very difficult, isn't it?
01:33362 keeps popping up in your mind.
01:35What's even more difficult is to think of absolutely nothing.
01:39But that's what we're going to try and do.
01:41We'll be looking at the man who invented nothing.
01:43People who buy and sell nothing.
01:45The size and shape of nothing.
01:47And the people who looked at nothing in a different way.
01:50And discovered how nothing holds things together and keeps them apart.
01:55So, if you've got nothing on, except the television, look this way and we'll look at nothing.
02:00Because there's more to nothing than meets the eye.
02:03Costume.
02:03Music, please.
02:04Music, please.
02:06Music, please.
02:06Music, please.
02:08Music, please.
02:11Thank you very much.
02:22A few years ago, a man called John Cage wrote a piece of music entitled Four Minutes, 33 Seconds.
02:31I would like, if I may, to play excerpts from that work this evening.
02:35Excerpts from John Cage's Four Minutes, 33 Seconds.
02:40Just bits of it, you see.
02:42The piece begins rather like this.
02:50In the middle of the piece, it develops a theme that goes something like this.
02:59And the whole thing builds to a climax and a crescendo and ends like this.
03:04Thank you very much.
03:07Thank you very much.
03:07Thank you very much.
03:15Oh, there's nothing there.
03:16Now, the question is, why did John Cage write that piece of music?
03:20It must have been crackers.
03:21No, the real question should be, why did he call it Four Minutes, 33 Seconds?
03:26Well, Four Minutes, 33 Seconds is 273 seconds.
03:30And minus 273 degrees centigrade is absolute zero, the temperature at which all matter ceases
03:38to function.
03:39So, in temperature terms, minus 273 degrees means absolutely nothing.
03:44Or, figure-o.
03:47La, la, la, la, la, la, la, la, la, la, la, la, la.
03:50Well, that's figure-o, isn't it?
03:54Throughout the years, music about nothing has made a fortune.
03:57Songs like I've Got Plenty of Nothing.
04:00There have been books about absolutely nothing.
04:02Here's a book.
04:05Nothing.
04:06I must remember to put something in there.
04:09There have been pictures painted about absolute nothing.
04:13A man called Ad Reinhart in America in the 50s used to paint totally blue or totally red
04:20canvases and sell them very well.
04:22But he felt that he hadn't achieved his ultimate ambition until he painted a completely all-black
04:29canvas.
04:30It did so well that he sold one for $12,000.
04:41All black.
04:42Now, how can people buy absolutely nothing?
04:46Well, the truth is, you and I and everybody else buys nothing practically every day.
04:52You've all got objects.
04:53Can we have a look at them now, please?
04:54Cullendars, chains, sieves.
05:00Lace.
05:01Let's have a look at it.
05:03What is it?
05:04Lace.
05:05Oh, good.
05:07Buttons without holes.
05:08A button wouldn't be nothing.
05:09A donut.
05:10What would a donut be without a hole?
05:14And the mint with a hole.
05:15Why do people go mad on the mint with a hole?
05:17Once you've eaten the mint, you don't taste the hole.
05:20Must be the sweet with a less fattening centre.
05:21People go mad on all the things because of the holes.
05:27They just wouldn't be the same without holes.
05:29Let's look at nets.
05:30Tennis nets, table tennis nets, football nets, cricket nets.
05:33What are they but holes tied together with a string?
05:36And holes are very important.
05:37What's the most important part of a door?
05:39The handle?
05:40The hinges?
05:41No!
05:42It's the hole it fits in.
05:44Because if you haven't got a hole, it's useless.
05:48Someone invented the wheel.
05:49And people said it was the greatest invention man had ever achieved.
05:53Nonsense.
05:55The greatest invention was the hole in the wheel.
05:58Because without a hole, it's useless.
06:00And if you put the hole in the wrong place...
06:04The wheel just won't work.
06:11Well, as somebody invented the wheel, someone also invented nothing.
06:17Or at least the figure.
06:19Nothing.
06:20You see, numbers were started by the Sumerians.
06:22And they passed this on to the Egyptians.
06:24And it was passed on to the Romans.
06:26But none of these people invented a number for nothing.
06:29This was left to a Hindu.
06:31What's a Hindu?
06:32Lays eggs.
06:33Now, the Hindus are tribes who live in northern India.
06:39And they developed a series of numbers where they had a different system, a different symbol, for each number from 1 to 9.
06:46Can you hold your cards up, please?
06:48We'll be in the second row, so we can see the numbers.
06:51There we are.
06:521, 2, 3, 4, 5, 6, 7, 8, 9.
06:54Then they had a different symbol for 10, another one for 20, another one for 30.
06:59And then new symbols for 100, and 200, and 300.
07:01And so one day, somebody said, hang on, let's scrap all these 10s and 20s and 100s and use the same symbols over again.
07:09But move them around.
07:11So that's what they did.
07:12Can I have the 2 and 3, please?
07:14Fine.
07:16So, that's what they did.
07:17You can put those down now.
07:20They moved the 2.
07:22To make 23, they moved the 2 over into the 10s column.
07:26See, so that's two 10s.
07:27Left the 3 in the units column.
07:29So that was 2 and 3, 23.
07:32To write 230, they moved the 2 over into the 100s column.
07:35So it was 200s.
07:36The 3 over into the 10s column.
07:39So it's 230.
07:41But hang on, that looks the same as 23.
07:44Unless you remember that for 230, you need a space.
07:48There.
07:49So, they put a space in.
07:52So that would be 230.
07:53And that would be 203.
07:57So now the system worked.
07:58As long as you remembered where the space was.
08:01So to remember where the space was,
08:03they put a ring round it.
08:06And the system was complete.
08:10The system was developed.
08:11And the Arabs took it off.
08:14And from Arabia, it came to Europe in about the year 1200 AD.
08:17But we still call these numbers Arabic numerals.
08:21But the system was so simple, you see.
08:23Everyone could do it.
08:25It was the end of the dark 80s.
08:26The beginning of the new learning.
08:29And man began to develop much more quickly from then on.
08:32And it was all thanks to that one invention.
08:36In fact, you could say that the greatest, most important invention that man has ever achieved
08:41was the invention of absolutely nothing.
08:51Now, each and every one of us, in fact everything, is made of smaller and smaller particles.
08:57This is a model of an atom.
09:01An atom is made up of a nucleus in the centre, with electrons whizzing round it.
09:07But you've got to realise that an electron is about a two thousandth the size of the nucleus.
09:13And the nucleus is only a ten thousandth the size of the atom.
09:19So really, an atom is composed of just a few specks of matter,
09:23surrounded by a great deal of absolutely nothing.
09:28Now, atoms join together and form molecules.
09:30A molecule of water has two hydrogen atoms and one oxygen atom.
09:35And the different molecules form together to make cells.
09:39In a man's skin, in a square centimetre, there are about ten million cells.
09:47A man is about two thousand million cells high.
09:51Now, if you took about seven million men and stood them on top of my head,
09:55I'd probably wobble a bit and go, ooh!
09:59But we'd stretch the diameter of the Earth.
10:02And the Earth is also made up of atoms and molecules,
10:05comprising a great deal of nothing and a few specks of matter.
10:10Now, the Sun is 109 times wider than the Earth.
10:13And they're separated by 93 million miles of absolutely nothing.
10:21Now, if you'd travelled to the Sun,
10:23at the fastest speed man has been able to travel,
10:27it would take about five months and it would get very hot,
10:29hotter and hotter all the way.
10:30But travelling at the same speed to get to the nearest star
10:34would take 173,000 years.
10:40And on the journey, you'd meet absolutely nothing.
10:45Now, that's the nearest star at four light years away.
10:49But the furthest star is at least 15,000 million light years away.
10:56So when you think about it,
10:58the universe, the solar system, the Sun, the Earth,
11:03a man, a cell, a molecule, an atom,
11:07are really specks of matter
11:09surrounded by an enormous amount of absolutely nothing.
11:14And yet, in our lives,
11:19we concern ourselves totally with those specks of matter.
11:23But just a few people concern themselves with the nothing.
11:30A man called Isaac Newton, one day,
11:33was standing under an apple tree.
11:37Ow! He thought.
11:38That's unusual, because it was a plum tree.
11:41You know, what confused him,
11:45or what made him think,
11:47was that the apple had fallen down.
11:49He thought, well, why didn't it fall up?
11:52Why didn't it fall sideways?
11:55And he found
11:56that every particle in the universe
11:59is attracted to every other particle in the universe.
12:02And the strength of that attraction
12:03depends on how close they are together
12:05and how big they are.
12:07And we're all here, on Earth, today,
12:09because the Earth is so big,
12:11its mass is so great,
12:12that it is attracting us,
12:14holding us down onto its surface.
12:16And that attraction, that force,
12:18is called gravity.
12:21I'm going to pull some equipment in here.
12:23Can you help, please?
12:28About there, I think.
12:29That should be all right.
12:30You stay there.
12:31Now, you may notice,
12:32when you drop something,
12:34that it may bounce,
12:35but it never bounces quite as high
12:37as the distance it dropped.
12:39Can you press that?
12:40Trigger there.
12:46We'll do that again in a minute.
12:47Hang on.
12:47Press that.
12:51That's enough.
12:52Because there's one other thing you may notice
12:54when you drop something.
12:56It accelerates.
12:57It speeds up as it drops.
12:59So let's have another go.
13:03Very good.
13:04Can you sit down?
13:05All right, pull it off with me.
13:06That's right.
13:07And then you can sit down.
13:09Lovely.
13:11Thanks very much.
13:13Will do.
13:14Now,
13:15this acceleration
13:16is caused by the gravity pulling it down.
13:18And you can tell,
13:20or you can see it work
13:21very well
13:22when somebody fells a chimney.
13:27Have we got a feller?
13:30I've got one hat.
13:31You put that on.
13:32It could be dangerous.
13:33Are you an expert at felling chimneys?
13:36Just an amateur.
13:37Oh, good heavens.
13:38Pull that string
13:38and then get out of the way.
13:41Step back here
13:42as soon as you've pulled it.
13:42Ready?
13:43Can you pull it
13:43flat against the ground?
13:45Ready?
13:45Go.
13:47Oh, hang on.
13:48The thing's come off.
13:49But it's coming.
13:51Timber!
13:51You did it.
13:57Congratulations.
13:58It worked very well.
13:59Thanks very much.
14:00Is there somebody else
14:01who'd like to have a go?
14:02Would you come and have a go?
14:03Because I want you to watch something now.
14:06As it falls,
14:08it does an odd thing.
14:09You see,
14:09the gravity pulls it down
14:10and the more it's tilted,
14:12the more the gravity pulls it
14:13and it tends to break its back
14:15before it hits the ground
14:16because the gravity is pulling it in the middle
14:18and the top end
14:19can't travel as fast as the rest.
14:21So we'll see if that happens now.
14:23Okay.
14:24Grab the string
14:24and as soon as you've pulled it,
14:29step out of the way.
14:29Ready?
14:30Pull!
14:32Timber!
14:37Thanks very much.
14:39Now,
14:40they were very enthusiastic about that.
14:42Did anyone else like to fill a chimney?
14:45Anyone else?
14:46Would you?
14:46Well, would you like to pick these pieces up
14:48and then we can get them out of the way?
14:49Come on.
14:49Come on.
14:49Grab a couple each
14:50and take them off to the side
14:51and the yellow bits
14:54and everything.
15:04And everything's cleared away.
15:06Thank you very much.
15:07Very enthusiastically done,
15:08I thought.
15:11And enthusiasts
15:12can often achieve things
15:14that experts don't quite manage to achieve.
15:17this is a picture of a man called Michael Faraday,
15:46who lived
15:47who lived
15:47at the beginning of the last century.
15:50And at that time,
15:50he was a bookbinder
15:51in London,
15:53quite near
15:53to the Royal Institution.
15:55And used to go to the lectures
15:57at the Royal Institution
15:58and listen to the great scientists of the day,
16:00like Sir Humphrey Davy.
16:02And he was so enthusiastic,
16:03he didn't only listen to every word,
16:05but he copied every word down
16:06in his own sort of shorthand
16:08and then went home
16:09and wrote everything out
16:10in the longhand,
16:12very neatly.
16:13And the lectures,
16:14he then bound together in a book.
16:18And you can still see the book today.
16:21Sir Humphrey Davy heard
16:22about how enthusiastic this lad was.
16:24So he eventually gave him a job
16:26as laboratory assistant
16:27at the Royal Institution.
16:29So the enthusiast
16:30was suddenly thrust
16:31into the middle
16:32of the scientific world
16:33among all the experts.
16:35One of the things
16:36the scientists were trying to do
16:37was to make a rod of metal
16:39turn
16:39by applying
16:41magnetic forces.
16:43No one
16:43could achieve this.
16:45But on the 4th of September,
16:481821,
16:52Faraday produced
16:53this equipment.
16:55A dish of mercury
16:55with the magnet
16:57in the middle.
16:59A free-swinging
17:00metal rod.
17:02And the mercury
17:03connected by wires
17:04to the rod
17:05and the wires
17:07passing through
17:07a power source.
17:09When he turned
17:10the power on,
17:11this is what happened.
17:24And Michael Faraday
17:25had invented
17:26the very first
17:27electric motor.
17:32Now, of course,
17:34this electric motor
17:34was very primitive
17:35and it would be many years
17:36before it was developed
17:37into a usable
17:38sort of motor.
17:39But it had set
17:40Faraday off
17:41on the road
17:42in which he would
17:43explore and discover
17:44many things
17:44about electricity
17:45and magnetism.
17:47You there.
17:48Which hand
17:48do you stir your tea with?
17:50Right.
17:51Right.
17:52I use a spoon.
17:54However,
17:54when you stir your tea,
17:57have you ever thought
17:58that only a portion
17:59of the tea
17:59touches the spoon
18:00and yet you just stir it
18:01or the tea
18:02starts to go around?
18:04Well, the same thing
18:05happens
18:05with this apparatus
18:06here.
18:07I've got a handle
18:08with two magnets
18:10on the end.
18:10It's my spoon.
18:12You see?
18:13And the two wheels
18:13aren't connected.
18:15But when I turn
18:16the magnets,
18:17it causes the other
18:20wheel to turn around.
18:21And there's no connection.
18:23And the faster
18:24I turn my spoon,
18:26the faster my tea
18:27goes around.
18:27And the reason
18:30for this
18:30is the magnetic field
18:33induces a current
18:34into this disc
18:35which pulls it round.
18:38Now,
18:38all you have to do
18:39is attach a pointer
18:40to this side
18:41and a piece of elastic.
18:43Turn that wheel.
18:45And the faster you turn it,
18:46the further over
18:47goes the pointer.
18:48The slower you turn the wheel,
18:50the more the pointer
18:51comes back.
18:51And that is exactly
18:53how a speedometer
18:55in a car works.
18:57Now,
18:58somebody else thought
18:59if you can pick things up
19:01with a magnet
19:01and you can also
19:02repel them with a magnet,
19:03perhaps if you put
19:04the magnet underneath,
19:06you could repel
19:06the other object
19:08upwards.
19:09And if you could do that
19:10with sufficient force,
19:11you'd combat the gravity
19:12pulling it down
19:13and you could get something
19:15to float in mid-air.
19:17Rather,
19:18like this.
19:21This piece of aluminium
19:38is floating
19:41on a magnetic field
19:43which is set up
19:43by these coils.
19:45Four coils,
19:47four magnets,
19:48whose force field
19:49is working in this direction.
19:51so that the
19:52piece of metal
19:54is in a sort of a trough
19:56that you can wobble it about.
20:00Now,
20:01if you put these coils
20:02in a row,
20:04you can get
20:05what is called
20:05a linear motor.
20:07That is,
20:08the magnetic field
20:09can be made to travel
20:10in waves,
20:12just like the waves
20:13coming up
20:13on the shore.
20:15When you do that,
20:16this happens.
20:18Can you come and hold this?
20:19It's just warm,
20:21but it's all right.
20:21Just hold it.
20:23Ready?
20:24And let go now.
20:28You can stand away now.
20:30Thanks very much.
20:31Were you a bit worried
20:32at that end?
20:34I thought you might be.
20:36Well, actually,
20:36this is not one linear motor,
20:39but two linear motors.
20:40This one
20:41is flowing in that direction,
20:42and this one
20:43from there to the middle
20:44is flowing in that direction.
20:45So they're sending
20:46the piece of metal
20:47backwards and forwards.
20:49But if we turned
20:50this linear motor around
20:51that way,
20:52the piece of metal
20:53would fly off the end
20:54at a pretty hefty speed,
20:56accelerating all the time.
20:59Oops,
21:00I missed it.
21:02Got it.
21:02There.
21:09Now, it's only
21:09ten years
21:11since linear motors
21:13were developed,
21:14but already
21:14about a thousand
21:16applications have been used.
21:17For instance,
21:17sliding doors in shops
21:19is the most
21:20common use
21:21of linear motors.
21:22But probably the most
21:23exciting use
21:24of linear motors
21:24is for high-speed trains.
21:27The metal,
21:27instead of floating
21:28up and down
21:29on the top,
21:30becomes the rail
21:31in the track.
21:32And the linear motor
21:33fits to the underside
21:35of the train.
21:36Already,
21:36there are experimental tracks
21:37in West Germany,
21:38in Dallas,
21:39and at Derby,
21:40in England.
21:40And it's hoped
21:41in the future
21:42that we will be able
21:43to travel on trains,
21:45traveling at incredible speeds,
21:47with no sound whatsoever
21:48and no friction,
21:50resting on magnetic fields,
21:53but giving us the impression
21:55that they're resting
21:56on absolutely nothing.
21:59Let's have a trick.
22:00I've got some cards here.
22:02Now, one of these cards
22:04is a red one.
22:05And I have a dice here
22:07made of absolutely nothing.
22:09OK.
22:10Can you hold the dice?
22:12Have you got it?
22:13You got it?
22:14Yeah.
22:15He's daftler than me.
22:17Throw the dice over there.
22:18I won't look.
22:20Ready?
22:20Go.
22:21And tell me
22:21what the top number is.
22:23Er,
22:24five.
22:26Five.
22:26Well, that's amazing.
22:28Five.
22:29Because
22:30five of these cards are black,
22:34but the number five
22:35is red.
22:38So,
22:39if you'd like to know
22:40how that's done,
22:41drop me a line.
22:42Johnny Ball,
22:42think of a number,
22:43but do include
22:43rather a large
22:44stamped addressed envelope.
22:46Till next week,
22:48I'd like to leave you
22:48with this thought.
22:50One day,
22:50the sun will expand.
22:52It'll be many,
22:53many years from now,
22:54but eventually,
22:56it will expand
22:56and expand
22:57until suddenly,
22:58it will collapse
22:59in on itself,
23:01dragging the planets
23:02with it
23:03and finish up
23:04with quite a small lump.
23:06What will have happened
23:07is the lump
23:08will be comprised
23:10of just those
23:11small bits of matter.
23:13And what will have disappeared
23:14is all that
23:16absolutely nothing
23:17that was holding it all apart.
23:20Long before then,
23:21will be nothing.
23:22And we're going to disappear
23:23now.
23:24But not yet.
23:26We will be back
23:27next week
23:28with another
23:28think of a number.
23:29Goodbye.
23:29Goodbye.
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