Atoms. They’re small.

Here’s something: before I can even begin to figure out how atomic clocks work, it may be helpful to understand what an atom is. An atom is the smallest thing that exists. Anything you can touch is made out of atoms. Lots of ‘em. There is literally nothing physical that’s smaller than an atom.

An atom is made out of subatomic particles, but these can’t be separated so they don’t count as being smaller than a whole atom.* These particles have Greek names (like Aristotle hahajustkidding). In the middle of the atom are neutrons and protons stuck together in a clump, called a nucleus. Around the nucleus are electrons, circling like the moon circles Earth.** The electrons don’t fly away from the nucleus because the neutrons and protons exert a magnetism kind of like gravity.

So, no, I still haven’t figured out how the atomic clock works. This is taking longer than I thought. I’ll be back as soon as have more info. Please continue to hold.

 

https://www.britannica.com/science/atom

*Ms Physics chimes in: “Atomos (Greek) ‘indivisible’ later proved incorrect!” Well, yes, that’s true. I don’t want you kids getting any ideas. Please, if you manage to isolate an atom—DON’T SPLIT IT!

 

 

** Another Western Civ Irregular Jeffrey K takes exception to me comparing an atom’s nucleus to a planet and electrons to orbiting moons. He says “Electrons don’t really orbit like planets– more like moths around a flame (without the usual fatalities). Also electrons are magnetic but the rest is held together by nuclear forces.” I said “So far as I know, nobody’s seen an atom because they’re so teensy.” So he sent me this:

 

https://www.school-for-champions.com/science/atoms_solar_systems.htm#.Xyk9hB17nzI

 

 

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Atomic Clocks

We’re now at the point where we can talk about…atomic clocks, which lose only one second every 100. Million. Years. Yay!

What is an atomic clock and how does it work? That’s an excellent question. Honestly, I have no idea. You would think, as an adult grown-up-type guy, I’d know something like that. I don’t. I avoided science classes in school so I could hang out in the art room.

I don’t know how you get atoms to float around in a tube so you can zap ‘em with radio waves until they change into a different energy state and bounce off a detector that counts the atoms in their new changed state and funnels the whole mess into a feedback loop…

I need to go away for a few days and marinade myself in sciency research until I figure this one out. I’ll be back. In the meantime, please enjoy this hold music—

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Just a second

Before I got side-tracked into digital clocks and watches, we were talking about satellites and the Global Positioning System. I mentioned that the satellites that send us navigational signals need to have an incredibly accurate clock aboard. Even a second’s difference in time between satellites’ clocks would change significantly your GPS data—and give you the wrong location.

So you’re thinking, “Well, Manders, those quartz crystal clocks lose or gain only 15 seconds a month. That seems pretty accurate to me. How you gonna improve on a system that measures 32,768 oscillations per second? How you gonna do that? How?”

To which I reply, with a rueful smile, “My friend, there is another clock yet to come, whose sandals the quartz crystal clock isn’t fit to lace. I speak of a clock that loses only one second every 100 million years!”

Really.

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32,768 oscillations per second

When you hit a tuning fork against something it vibrates, giving a specific musical note.

We learned that a digital clock is regulated by measuring how many times a quartz crystal oscillates per second—32,768 times. How does it count all those vibrations so quickly? Here’s how: the crystal is purposely cut with a laser to exactly the size and shape (the shape of a tuning fork) that will produce 32,768 oscillations in a second, then stop.* The electric circuit zaps the crystal with electricity, which makes the crystal vibrate until it returns to its original shape. When the vibrating stops, exactly one second has passed. The stopped vibrations trigger the circuit to move the second hand and give the crystal another zap.

The same principle applies in animated entertainment for children. The mouse hits the cat, who oscillates for a second, then resumes his former shape.

Here’s how a tuning fork works: https://www.youtube.com/watch?v=hW-igtIn3A8

Basics of LC oscillators and their measurement

https://en.wikipedia.org/wiki/Crystal_oscillator

* “Because 32768Hz can be so conveniently divided to give a 1 second pulse, it is a very popular size for it to be cut to. Manufacturers can bang them out and be sure they will sell.” https://www.quora.com/Why-does-Quartz-vibrate-exactly-32768-2-15-times-per-second

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The liquid crystal display explained!

Three inventions moved clocks and watches away from being mechanical/analogue so they could become digital: The quartz crystal, the circuit board and the liquid crystal display.

Okay, I sort of explained how a battery works. I kind of explained how a quartz crystal works. The circuit board was easy—even a shmo like me can explain printed metallic ink on a plastic card. But—liquid crystal display? I started this post about 17 times and kept getting lost in the weeds with carrot juice and double melting points and twisted nematics and polarization…

Let’s start here: analogue clocks and watches were inaccurate because they have physical, mechanical moving parts. So we replaced the wound-up mainspring with a battery. We replaced the balance wheel with a vibrating quartz crystal. Now we need to replace the moving mechanical gears, hour-hand and minute-hand with a digital (just the numbers) display of the correct time. How do we do that?

A digital wristwatch made by the Japanese company Casio.

Instead of mechanical gears and hands, we’re going to use electricity and light.

We want a watch-face that will light up and show us what time it is. We want most of the face to light up except the numbers, which should be black so we can read ‘em easily. We’ll block the light in the shape of each number so it shows up black. The numbers will change every minute, so we need a way to change the blocked areas every minute.

In order to block the light, we need a filter. The filter lets us control which rays of light pass through and which rays get blocked. A filter could be a wall of liquid filled with crystals that all face the same direction. The lined-up crystals let the light pass through. We’ll sandwich this wall between 2 plates of glass. The crystals still let light pass through—until we zap them with a little electricity. The electricity upsets the crystals so they don’t line up anymore and light can’t pass through.

We’re only going to zap in certain areas. We want those certain areas to be shaped like numbers. For instance, when we zap the glass in the shape of a ‘3,’ those crystals in the 3-shape get upset and don’t line up with the rest of the crystals in the wall. Light can’t pass through the 3-shape, so we see a black ‘3’ on a lighted watch-face.

Just like on a circuit board, we’ll print the numbers onto the glass in ink. This ink is transparent—and it conducts electricity. Each number is designed as a 7-segment figure, so we can zap only the segments that form a ‘3,’ or whichever number we want. Each segment is wired to the battery.

This is the principle behind LCDs. It’s a simplification. I left out a lot of stuff. But you get the idea, right?

https://electronics.howstuffworks.com/lcd.htm
https://electronics.howstuffworks.com/gadgets/clocks-watches/difference-between-quartz-and-liquid-crystal2.htm
http://www.madehow.com/Volume-1/Liquid-Crystal-Display-LCD.html

Many thanks to a couple of the Western Civ Irregulars, Diana (Ms Physics) and engineering-wiz Don M—both pals of mine since childhood. They pointed me in the right direction when I couldn’t find a way to explain this one.

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Circuit boards

Three inventions moved clocks and watches away from being mechanical/analogue so they could become digital: The quartz crystal, the circuit board and the liquid crystal display.

This will look better when I paint it. For one thing, the board will be a lovely green. The bigger, more complicated circuit boards look like city maps.

If you’ve ever wired something—like a lamp—you’ll remember getting out the needle-nose pliers and wire-cutters, maybe a razor blade to strip the insulation off the wire ends; you wrap the exposed copper wire around the appropriate screws then tighten ‘em up so the wire stays put…I’m trying to imagine how you would wire something as minuscule as the insides of a watch. Wires would need to go from the battery to the quartz crystal, back to the battery with a detour to power the hour, minute & second hands after counting how many oscillations the crystal made.

The circuit board is a flat card made of plastic or resin. Instead of wires, circuitry is printed right onto the card in metal ink. A circuit board can get a complicated electric network crammed onto a very small area. A small circuit board in a watch can direct electric power from a battery to the quartz crystal and anything else inside the watch .

You can see the circuit board at 27:20 https://www.youtube.com/watch?v=SFiq8WDx5Is

The History of Circuit Boards

https://www.pcb-solutions.com/pcb-market-monitor/the-history-of-pcb-infographic/
Those old discarded mass-produced watches and circuit boards can become playthings for someone with electrical knowledge—http://www.angelfire.com/ut/horology/quartz.html
https://sound-au.com/clocks/timebase.html

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Quartz crystal

Three inventions moved clocks and watches away from being mechanical/analogue so they could become digital: The quartz crystal, the circuit board and the liquid crystal display.

Quartz is a common mineral that does this weird thing: it generates a tiny bit of electricity if it’s squeezed, and vibrates when you send an electric charge through it. Watchmakers cut quartz into a shape that looks like a tuning fork, so it vibrates like a tuning fork.

So if we just squeeze the quartz—I’m not sure if this is really the way it happens…

…wow! It works! (photo credit: KTUL.com)

Amazing!! (photo credit: Google Earth)

Okay, okay, that was just a gag. You knew that, right? Just a teeny tiny electrical charge passes through the quartz crystal to regulate the watch.

“Inside a quartz clock or watch, the battery sends electricity to the quartz crystal through an electronic circuit. The quartz crystal oscillates (vibrates back and forth) at a precise frequency: exactly 32,768 times each second. The circuit counts the number of vibrations and uses them to generate regular electric pulses, one per second. These pulses can either power an LCD display (showing the time numerically) or they can drive a small electric motor (a tiny stepping motor, in fact), turning gear wheels that spin the clock’s second, minute, and hour hands.” https://www.explainthatstuff.com/quartzclockwatch.html

https://electronics.howstuffworks.com/gadgets/clocks-watches/digital-clock2.html

A Short History of Digital Clocks and Watches

https://h2g2.com/edited_entry/A1006534

A Brief History of the Wristwatch – Part 1

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How batteries work

A battery is a container—inside it are chemicals that react to metal or each other. Their reaction releases energy in the form of an electric current. The battery directs that current (electrons) to a negative terminal. The positive terminal on the other end of the battery absorbs the current. The electrons leave the negative terminal when it’s connected to something like a flashlight, light up the bulb, then return to the battery at the positive terminal.

https://electronics.howstuffworks.com/everyday-tech/battery1.htm
https://www.thoughtco.com/battery-timeline-1991340

https://www.explainthatstuff.com/batteries.html

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The Hamilton wristwatch

It’s the hairspring that made watches—which are just little clocks—possible. You wind up the hairspring and as it uncoils it releases energy to power the watch. Since the hairspring is small, watchmakers could miniaturize the balance wheel and gears, too.

But if you really want precise timekeeping, a watch’s design must have as few moving parts as possible. Watches were mechanical. Mechanical or analogue machines (a clock or steam engine or internal combustion engine) need constantly to be fussed with: you have to oil the gears; or correct for changes in temperature or humidity; friction slows down the machinery; you have to wind it or feed it fuel…if you could just get rid of those moving parts, you’d have a more reliable watch.

A small electric battery

The switch away from analogue didn’t happen all at once. When batteries became small enough, the first electrically-powered watch showed up in 1957. It was battery-operated, but still had mechanical moving parts, like gears and a balance wheel. It was made by the Hamilton Watch Company of Lancaster, Pennsylvania.

Inside the Hamilton wristwatch

http://www.crazywatches.pl/hamilton-titan-500-electric-1957

The wristwatch’s battery is really small

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WWI flying aces and wristwatches

For a long while, wristwatches were thought to be fashionable for ladies only. The guys stuck with their pocket watches—until the First World War. WWI was the first time airplanes were used in combat. Sometimes several airplanes were used for a coordinated attack, which meant they had to arrive at the target at the same moment. When you’re hundreds of feet in the air, working a joystick and firing a machine gun, you don’t have enough hands to also pull out your pocket watch to see if you’re on time (why didn’t they put a clock in the plane’s dashboard? I don’t know).

Does this happen to you? I started out drawing a wristwatch-wearing WWI fighter-pilot and he turned into Joe Kubert’s angst-riddled Enemy Ace Hans Von Hammer and his puppy, Schatzi.

Likewise, if infantry soldiers in the trenches were ordered to open fire on the enemy simultaneously at a pre-planned time, a timepiece on your wrist is a whole lot more convenient than one in your pocket to count down the seconds while you’re holding a machine gun and a shovel.

So designers began designing manly-looking wristwatches for the guys.

https://gallantry.com/blogs/journal/the-history-of-watches#
https://www.watchmaster.com/en/journal/stories-en/the-history-of-the-wristwatch

https://en.wikipedia.org/wiki/Enemy_Ace

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