[Door opens, footsteps]
[Jazzy music: 'The Russians Are Coming' - Val Bennett]
[mechanism clicks]
[clanging and whistling increasing in pitch]
[clank] [gong clashes]
Tim: There's something very fascinating about time-keeping contraptions.
I've made quite a few myself.
But I have to say I have great trouble making them very reliable.
And when I actually need to know the time I look for the nearest quartz watch.
It's easy to forget just how clever these little things are
particularly because you hardly ever need to do anything to them.
And they're so accurate they rarely need setting.
So in this programme, Rex and I are going to rescue them from obscurity
and look at their history and how they work.
The earliest time-keeping device was simply a stick in the ground.
[thunk thunk]
The ancient Egyptians measures the angles of the shows it cast
and the Greeks measured their length.
This may seem rather crude, but people didn't usually need to know the time very accurately.
It was usually quite good enough just to have some idea how much daylight was left.
And the stick does have the enormous advantage, like the quartz watch in fact, that it never needs setting.
The Greeks and Romans also had water clocks,
but these were mostly just bowls with a hole in.
Greek controller: Clock started!
they were used as timers for rationing irrigation water.
[drip drip drip] Man: Humming.
Irrigation controller: That's it, time's up!
Man: What? My campus is hardly dampus!
Tim: They were also used in the courts for timing the speeches. Speaker: Saepe numero, patres conscripti, in hoc ordine interfui...
Tim: Unscrupulous senators are said to go to great lengths
to make their opponents thirsty to shorten the speeches.
Speaker: ...decreta postularentur...
Speaker: Ahhh!
Gracias de viago.
[munches food]
...et in ordine, quiscue...
[makes dry mouth noises]
(gasps) Aqua!
[drip drip drip drip] [slurrp]
Ooh!
[Medieval monks chanting]
The first people to attach any importance to accurate time-keeping were the medieval monks.
They had up to 9 services a day, and it was considered vital to hold them at precisely regular intervals.
At first these intervals were set by water clocks,
but at some point in the late 13th Century the first mechanical clocks appeared.
[Bell ringing] Initially they didn't bother with dials,
[Bell continues] the important part was the bell which summoned the brethren to prayer.
Our word, 'clock ' comes from the French 'cloche' meaning bell.
This particular clock is one of the oldest still working in a church, it's about 400 years old.
Although it obviously doesn't look at all like a quartz watch,
the principles on which it works are really remarkably similar.
If I take a quartz watch to bits...
[quiet clicking and unscrewing noises]
You can see there's basically 4 parts inside:
The display,
the battery,
the silicon chip which is under this blob of plastic,
and this little tin can which contains the actual quartz crystal.
It's actually a lot easier to understand how one of these things works
by looking at the clock in a bit more detail first.
The display's obviously doing the same thing as the dial on the clock,
and the battery powering the watch is doing the same thing as the weights in the clock tower. [clunk clunk]
But also the crystal is actually providing a regular beat,
in very much the same way as the swings of the pendulum,
And the silicon chip is controlling the whole thing just like the gearing.
The heart of the gearing mechanism is the escapement, which interacts with the pendulum.
[clunking of gearing] It pushes the pendulum to keep it swinging,
at the same time the escapement is held back by the pendulum, regulating the clock's speed.
[clunk clunk clunk clunk]
[clank] [whirrrrrrr]
[bell tolls] [whirring continues]
[bell tolls]
[bell tolls] [clicking and whirring]
[clicking and whirring slows down before coming to a halt]
The properties of the pendulum were discovered by Galileo in 1590.
To mask the pong of the peasant congregation,
Priest: ewww uh ugh!
Priest: Censer pronto!
the priests used a swinging censer to fill the church with incense.
Galileo realised that the censer was taking exactly the same time
to swing from side to side, however far out it went.
Man: Per meso?
Galileo: U-no, do-eh, treh. U-no, do-eh, treh.
(louder) U-no, do-eh, treh. U-no, do-eh, treh.
Tim: He had trained as a doctor and used his pulse to time the swings.
All: U-no, do-eh, treh. U-no, do-eh, treh.
Tim: Galileo was in need of an accurate clock for some of his astronomy observations.
So he simply set up a swinging weight in his observatory
and paid a man to count its swings all the time.
Gallileo: Ahhh.. Nastelis, stasteros. Man: . z Z Z Z Z
Gallileo: Meramelios! A belieze a belieze a...
Gallileo: MAH! Coza fie!
[Rex's footsteps]
Tim: The solution to this problem was to fit the pendulum to a mechanical clock.
And this has remained the basis of clockwork ever since.
[running water]
This is the escapement wheel and pendulum
of a water clock I'm building for Felixstowe town.
Rex: The water acts like the weight on the church clock,
pushing the escapement wheel round.
The escapement interacts with the pendulum in the same way.
[running water]
No matter how far the pendulum swings,
it always takes the same time.
The only way to alter it, is to raise or lower the weight.
[running water]
[Door rattles] [Tim's footsteps]
Tim: It's not obvious how a lump of quartz could possibly
do the same thing as a pendulum, but it really is quite similar.
The quartz does move.
This is a bit of crystalline material, similar to quartz,
sandwiched between two bits of metal.
And if I connect this up...
I think we should be able to see it move.
[click click as current is connected and disconnected]
The electricity is making the quartz distort.
This was discovered by Pierre and Marie Curie in the 1880s and called the piezo-electric effect.
In the watch it's used to make the crystal vibrate.
Here I've cut a crystal out of its tin can
and under a magnifying glass, I think
you can see it's cut in the shape of a tiny tuning fork.
It vibrates in exactly the same way as an actual tuning fork. [clank]
[tuning fork hums at 440Hz]
These vibrations have a stable natural frequency,
just like the swings of a pendulum.
Though in the quartz crystal, the movement's much to fast and small to be visible.
The piezo-electric effect also works in reverse.
So if I distort this cylinder of crystalline material,
by squashing it, it actually creates some electricity.
[creaky sparking]
This is actually the crystal out of a piezo-electric gas lighter,
and err, this is how these things work.
This is also used in the watch.
The battery powers the chip,
and keeps the crystal vibrating.
This vibration creates stable electrical pulses,
which are fed back to the chip.
Interacting in a similar way to the pendulum and escapement.
The chip then powers the display.
Although this basic idea of a bit of vibrating quartz is really quite simple,
it's only recently replaced clockwork,
which had been continuously refined ever since its first monastic appearance in the 14th Century.
This collection is in Bury St. Edmunds, and the curator is Lord Middleton.
Tim: Well from the early church clocks, the clocks quickly
became much more elaborate and more lavishly decorated.
When did the first portable mechanical watches or clocks...
Lord Middleton: Around about 1450. A Peter Henlein,
this is an example of one.
You can see it's a fairly sizeable machine, not exactly portable,
you'd have to have a very tough pocket to put it in.
Tim: You obviously couldn't fit pendulums and a weight in a thing like that though, could you?
Lord Middleton: No, you couldn't, no. Th-th-that really would be ridiculous.
Erm, no, these were spring driven.
This one here, for example, is a spring-driven clock.
There is a false pendulum on it, if we set it ticking...
in fact it's not really a pendulum, it's just a balance.
But the other thing about it, is how amazingly thick they are,
springs inside the barrel here.
And they work reasonably well,
but again, you'd have to check it every so often with a sundial.
Hence the frequency of sundials in every church.
I'm certain because of people needing to alter their watches.
Tim: Is the jewelled one, would that be a ladies' watch or would it...?
Lord Middleton: No, I think it's big enough for a gentleman.
I mean, ladies did wear watches like this,
they used to wear them on a long chain around the neck.
Tim: Watches like this were obviously very expensive.
and could only be bought by very rich people.
The first really cheap, mass produced, clocks and watches,
started being made in America in the 1840s.
Lord Middleton: The one over here which I like particularly because,
it's rather splendid, it has a railway time keeper written all over it.
It's a sure sign of really poor quality.
I don't know how American railways were run, but they rarely ran on time.
But if they were run according watches like this, they'd never have gone anywhere.
[factory whistle] Tim: Not only could ordinary people start to afford a watch,
with the coming of factories and railways, they actually needed one.
Man: Always late, plenty of time to catch a train, but...
However watches were still set by sundials [train hoots] [train starts to move]
so the time was slightly different in every town. [man pants and huffs]
Man: I know my watch is right, so why has the train gone?
Railway man: The train left on time sir! Man: Oh no no, it should have 5 minutes at least.
Man: What's happenin? Railway Man: Well you watch is on local time you see.
Railway man: We run on railway time 'ere. Train left when it should have done. [Man growls]
Woman: You! You let the train to go early! Now get him Wolfie! [Dog barks] [railway man yelps]
The idea of the wrist-watch is surprisingly recent.
They first became popular among artillery officers during the first world war.
It was a considerable technical feat to miniaturise all the parts to this extent.
Mechanical wristwatches are among the most sophisticated mechanisms ever made.
And have always been regarded as treasured possessions. [girls singing]
Girls: # For Auld lang syne, my dear,
# for auld lang syne.
# We'll take a cup o kindness... #
Sally: I'm SO proud. Oh just wait until the gang sees this!
Sally: Hey kids! Come on and run in!
Sally: Oh it's just perfectly perfect.
And so are you, both of you. Mom, and Dad.
Dad: Well Sally, you're our big girl now.
Dad: Mother and I wanted our present to tell you just how proud we are of you.
Girls: Why, why what is it? [excited chatter]
Tim: Today it may seem obvious that electronics provides a simpler way to miniaturise the watch.
But it wasn't until the '60s that all the parts became small enough to make the idea practical.
This is the first electric watch introduced by the
Hamilton watch company in America in 1956.
Inside it doesn't really look very different
from an ordinary mechanical watch.
There's a little balance wheel, there's a tiny electromagnet
on it which keeps it moving backwards and forwards.
The really remarkable thing was making a battery this small.
Though most of the development work on this was done by the military.
Mainly for use by spies and their radios.
The next electric watch to appear was far more revolutionary.
This is the Bulova Acutron, it's got
two tiny electromagnets you can see here.
Speaking Clock: At the third stroke, it will be 4:37 and 50 seconds.
[pip][pip][pip]
Voiceover Man: The Bulova Accutron uses
a new electronic time keeping principle:
A tuning fork. Listen... [364Hz hum of tuning fork]
A tuning fork to give you accuracy to within a minute a month, guaranteed!
Never bet against a Bulova Accutron,
The most accurate watch you can buy.
Tim: You can see this easier on this Bulova clock.
Erm, if I pop a battery in i think you'll be able to see
the tuning fork here start to vibrate.
This really is an exact mechanical equivalent of the quartz watch.
The idea of using quartz was nothing new.
The first quartz clock had been developed as early as 1929,
in the Prolific Bell labs that also invented the transistor in the '40s.
But these quartz clocks, like this German one, use much larger bits of quartz.
That's the quartz crystal at the bottom. And rather bulky electronics.
This is the, er, first true quartz watch.
Introduced in 1967 by the Japanese firm Seiko.
The Americans then regained the lead, and
the Hamilton watch company then introduced the pulsar.
This is the first solid state watch with no moving parts.
Woman: These are rotary watches:
This one has a traditional Swiss movement and a very handsome face.
This is a rotary quartz watch, devastatingly accurate.
This is a quartz watch too, but it's like a little computer...
You press this little button, and Look!
First the time,
then the day and date,
and then the seconds.
Very clever. It'll look smashing on your wrist.
Rotary every time.
Tim: The bright red displays on the first digital watches
used so much power, that they could only be switched on occasionally,
when you actually needed to know the time.
The first watch to um, have a liquid crystal display was, er, this one.
This uses so little power that the display could be left running.
This doesn't work anymore, the early liquid crystals were rather unstable.
Today this problem's been solved and liquid crystals
been made to do some quite remarkable things.
Whole windows like this are being developed
This is a bottle of liquid crystal, it's actually a liquid.
And the watch display is made by sandwiching it between 2 bits of glass.
If I clip them in here, and put a drop of liquid on top,
it'll slowly sleep, seep into the gap.
(whispers) Whoops!
(mutters) ...mop up the surplus...
Now these two bits of glass are coated with a square of
a transparently thin metallic layer that can conduct electricity.
So if I now... [buzz] whoops! ...connect it up.
One on the top here.
And er, one on the side.
It doesn't appear to do, doesn't appear to do anything at all.
What we need to make a complete display is, um, a pair of Polaroid sunglasses.
If I hold one lens behind the other,
and rotate it, you can see it goes from light to dark.
Well, if I now, um, put the sunglasses in the clip as well...
one lens in front of the sandwich, and er, one lens behind... Like that.
And now I connect it up again, you should be able to see...
the electricity has the effect of polarising the liquid crystal material.
I can show you just how little electricity this er, needs to make it work.
If I hold onto one wire, simply touching the cell with my other hand
is enough to make it work, although the electricity's
got to pass through the resistance of my body.
To make the complete watch display, the metallic film is simply split up into segments,
each of which can be separately connected.
This liquid crystal display is all still connected up, but
of course it's completely invisible until the polaroids are in place.
And a real watch display also needs bit of aluminum behind to reflect the light.
The chip in a quartz watch is equally ingenious,
here we've made up part of the circuit in separate stages.
The first one keeps the crystal vibrating.
This one divides the output from the crystal,
to give a pulse every second.
This one counts the pulses, you can see the lights coming on in sequence.
Finally this one converts the count to a random looking array of lights.
Arranged in the right places though, these create the familiar digital numbers.
[clicking of lamps into clips]
The idea of a digital display wasn't new,
it had appeared several times in the clock's history.
This is an illuminated night clock from the 18th Century.
[rattle] [click] [rattle] Electromechanical digital clocks started becoming popular in the 1960s.
[rattling and clicking continues]
But although digital displays tell the time very clearly, they do still have their drawbacks.
[Running man pants]
Man: I can't bear to be late for the opera, I wonder that the time is...
umm 5:49, and then if I can be there by about 6:02, it won't start before then... Needn't be 13, no no...
[lady's footsteps] ...it must be 13 minutes. Excuse me Madam,
I wonder if you could tell me what time it is. Woman: Yes, love. It's ten to six.
Man: Ten to six! Oh good heavens! [Man's running footsteps]
[Dog pants]
[Opera singer singing]
Man: (whispers) Excuse me. Oh I'm so sorry. [people sighs and tut]
[Opera singer continues]
[Man's watch bleep-bleeps] Crowd: Really!
Tim: Today, dial watches are back in fashion,
but now they're all quartz-controlled.
The crystal, the battery and the electronics are
almost the same as they were in the digital watch.
But now there's a tiny electrical motor driving the hands round,
instead of the liquid crystal display.
Although the quartz watch is very accurate, it is still affected by temperature.
I set two watches to exactly the same time a few hours ago,
and I put one in a low oven.
If I take it out again now...
It looks a bit of a mess, need to take this bit of plastic off.
And the liquid crystal display goes completely black, it stops working above a certain temperature.
But I think if I leave it to cool down now, you should be able to see
that the quartz has been affected by the heat, and they no longer tell the same time.
Of course watches don't usually get quite so hot,
but even small day to day temperature variations do mount up.
Keeping quartz crystal at a precise even temperature greatly increases the accuracy.
This is a device for timing the accuracy of watches,
and it has to be accurate to 1/100th of a second a day.
It still works by quartz, but there's a tiny heating element
inside which keeps the crystal at a very even temperature.
I'm going to use it to compare the accuracy of a mechanical watch and a quartz watch.
This is one of the most accurate mechanical watches ever made,
it cost 8,000 and it is a work of art.
If I put it on the block,
Have to wait, er, a few seconds before it starts to read.
And you have to average several readings.
Over about a minute I worked out that this one was averaging about 2 seconds a day fast.
Now if I compare this with a £1 quartz watch, it's on a different setting...
You can see this is averaging less than a second a day fast.
In general quartz watches can be about ten times for accurate than mechanical ones.
Rex: Some time ago I bought a cheap digital watch from a filling station.
It worked perfectly for about 4 months.
Then the battery failed, so I set about to repair it and realised
that the cheap plastic case was actually physically welded together,
and there was no way you could actually get at the works.
So I set about it with a hot scalpel blade, and halved the watch,
and I eventually got to the watch compartment and found that the replacement battery
I'd got was much larger than the original, so I then had to
modify the inside of the watch, to accommodate the new battery.
And that meant making new contacts for it etc.
Eventually I got it together, took about 2 and a half, 3 hours,
and the watch worked perfectly, and I was very pleased, very satisfied,
it's lovely repairing something that was never designed to be repaired.
But unfortunately my satisfaction didn't last very long, the following day the strap broke,
so I had to throw it away. Much to the amusement of everyone in the workshop.
Tim: I have to admit, I don't wear a watch myself,
but in comparison with my own clumsy timekeepers, it's impossible not to admire the things.
There really is something very satisfying and elegant about the way they work.
It's a shame really that they cost so little. This one only cost 60p.
People seem to regard them as almost totally disposable.
Watches certainly aren't the treasured possessions that once were.
[Explosion from oven]
*giggles* Whoops!
Wasn't it shut before? I thought..... (fades out) [Jazzy music: 'Take 5' - Dave Brubeck]