The earliest known pocket watch was devised by German locksmith Peter Henlein around 1505. These small, globe-shaped mechanical brass clocks, known as “taschenuhr”, were worn as accessories and trinkets by the upper class, much as chihuahuas are employed today.
Besides acting as Plague-era bling, these wearable clocks marked the first use of spiral mainsprings, metal torsion ribbons that store the potential energy that drives a timepiece. The energy stores in a mainspring keep a watch ticking, but they’re not limitless. Eventually, they get used up countering oscillation-impeding inertia and friction. And therein lies the problem.
See, mechanical clocks rely on an oscillator — the watch’s inner movement, or a grandfather clock’s pendulum, say — to control the system’s frequency, which is how the clock maintains accurate time. But friction robs this oscillator of a tiny bit of energy on every stroke. Minute by minute, that adds up; as the oscillations slow, the timepiece’s can lose a few seconds of accuracy a day. A mainspring’s purpose is to counterbalance that effect, continually adding stored energy to the system to keep things on track. Winding a clock, either with the watch crown or a key, adds to the mainspring’s potential energy. And you need to do it every 40 hours or so to stay current.
In addition, the mechanical watch’s reliance on minute, delicate, fail-prone parts that are easily affected by temperature fluctuations and magnetism demands regular and often costly readjustments, making analogue watches more expensive and less accurate than their digital successors.
Then there’s electronic movement, or crystal oscillation, which leverages a vibrating hunk of piezoelectric quartz to generate an electrical signal with a specific frequency, rather than rely on a series of gears and pendulums. Piezoelectric materials create electrical currents when stressed — in this case, the material is expanded and contracted. Conversely, the same piezoelectric material will vibrate when exposed to an outside current. The crystal’s size and shape determine the frequency it produces — known as the resonant frequency — typically in the kilohertz to hundred megahertz range. Early devices relied on naturally occurring quartz; however, the use of synthetic quartz is nearly universal these days.
High-stability frequency crystal oscillators — those suitable for clocks — were developed in 1928 by Warren Marrison of Bell Telephone Laboratories and have since become the most widely-used means of telling time in the world. Losing just one lost second every 30 years, quartz movement is orders of magnitude more accurate than mechanical designs. As such, more than two billion quartz oscillators are manufactured annually for use in personal timepieces, electronic circuits, and radio transceivers.
While crystal oscillators are susceptible to temperature, humidity, pressure and vibration fluctuations, even inexpensive watches are designed to minimise these environmental detractors. The oscillator is shaped like a tuning fork and designed to vibrate at exactly 32,768Hz (that’s 2^15 cycles per second, from which a steady, second-counting 1Hz signal is derived). In addition, many watches feature inhibition compensation. That is, they’re intentionally built to run fast, and programmed to a set number of crystal oscillation cycles at a regular interval. This allows the manufacturer to measure and store the timing information in non-volatile memory on the chip, rather than expend the cost of cutting the crystal precisely.
So just as mechanical clocks overtook the sun dials and water clocks before them, they too have been eclipsed by a more accurate method of counting seconds. And who knows? Digital watches giving way to something even more precise can only be a matter of time. [Wikipedia 1, 2 - How Stuff Works - NIST]
Picture: jecka/Shutterstock
hahaha well done good ser.
And yet, Analog watches are so much prettier.
Let's face it, while they are convenient (I hate it when I forget my watch and have to check my phone), if we REALLY wanted to know the exact time, we'd all have atomic clocks on our wrists. Analog is worn more these days for aesthetics. The fact that they lose a few seconds a week isn't really a problem for most people.
+1. Outside of sporting activities, few things are tackier than a grown man wearing a digital watch.
I'm against atomic clocks on principal. When will people learn - you can't hug your children with nuclear arms!
Ummm not entirely sure you know how an atomic watch works... >_>
Plus I don't think any if them would work in Australia
Whoosh
not necessarily, it isn't just about aesthetics. I prefer using an analog watch at work (as opposed to pulling out a stopwatch) when measuring my patient's heart rate and respiratory rate. It's a lot simpler and more efficient to use.
the fact that it looks nice is a bonus
Note sure the distinction meant here is face design. Many analogue faced watches are quartz movement. Rather than unreliable overpriced micro engineering.
Was this article written by an american for an american audience? We call them petrol stations in Australia. Not "gas" stations. Stop eroding our language.
You must be new here. We're on the Australian branch of an American website.
I realise that but they DO have editors who should check such things IMO.
By Jove! What's to be done with these insolent ninnyhammers!? Do they truly expect one to interpret such cretinous warping of one's mother tongue on one's own!?
To cast one's eyes upon this blatant disregard for our sacred lexicon is to be bescumbered by the filthy words of peasants!
+1 internets for you.
Win.
I call them Petroleum Outlets
When I fill my car up, I say I need Vespene Gas
Does your car tell you, "insufficient Vespena Gas" when it is running low?
Remember that most "analogue" watches are still powered by quartz action....
For a truly analogue mechanical watch as the story intimates, expect to pay a significant premium.... (for a less accurate device)
But who needs either of these when an atomic clock generated GPS time synchronising signal is available almost anywhere on earth
The timestamps in GPS signals aren't intended for time accuracy though. Each satellite will tell you a slightly different time because of the distance involved, which GPS then uses to triangulate your position. If you were going to try to set your time to the GPS signal, which signal would you use? Which one of the satellites is accurate to where you are?
You're wrong. http://ilrs.gsfc.nasa.gov/docs/timing/gpsrole.pdf
No, I'm not. Time can be extracted from the GPS signal under strict conditions but it isn't the intention of the GPS system to provide precise specific time. To get a precise time indication from a GPS signal, the exact position of the receiver needs to be known (in all three dimensions), so that the distance to the satellite can be calculated based on the orbital position the satellite reports itself to be in when it transmits the signal. Changing the position of the receiver by even a metre introduces errors in the calculation. The document you linked says as much.
Atomic clocks are fitted in the GPS satellites for period precision, not for specific time precision. Yes, it can be calculated if you're in a known fixed position and you never move, but that's incidental to the design of the system. If you want time precision on Earth, you use a terrestrial atomic clock, which is what is used when the satellite clocks need correction.
Edited to add: that document is also very outdated. Selective availability was disabled 12 years ago.
Last edited February 18, 2013 5:20 pm
You are obviously a troll.... (don't worry, sometimes trolling is fun, you may catch a marlin.)
Have a look into the most common uses of the GPS signal, one of those isn't for navigation or positioning, but for synchronising clocks...
Enjoy life or give up.
Nope, I just have extensive experience working with the GPS system. The clocks in GPS satellites need regular synchronisation from terrestrial clocks, rather than the other way around. Time sync is a side effect of the system, not a function, and it's not as accurate as terrestrial solutions.
Last edited February 27, 2013 7:44 am
Thanks everyone for the constructive input...
@marcusnuccio linked article (Obviously a person of few words)
The conclusion of that linked article is:
"The time, time interval, and frequency dissemination capabilities of GPS have already been tested.
No other single system has such potential for global, accurate, and inexpensive time and frequency control."
Pretty much what I first said....
(Apparently now SA is turned off so some of the doncerns in that article are moot, however the USA is able to turn on SA at any time, degrading the sub nanosecond accuracy some civililian users require, me I'm usually pretty happy if my computer clock is within 1 second, and my MCU's always have their own oscillators, independent of UTC.....)
Wikipedia simplified explanation of interaction of the C/A and P codes:
(Implementation of acquiring a precision GPS signal (Military and authorised civilian (I think some aviation users access this signal) use only) )
"It was expected that the receiver would first lock onto the relatively simple C/A code and then, after obtaining the current time and approximate position, synchronize with the P-code."
The initial download of the GPS almanac and synchronisation of the reciever takes some time, because the GPS receiver is establishing the highest likelihood, position and clock synchronisation... From there, position variations are able to be tracked with "High accuracy" (as 1 m position difference translates to around 3 ns, the ~ +/-10m Coarse/Acquisition GPS signal will give the average user a 30ns accurate timing signal...
Bottom line, the GPS signal IS intended to disseminate accurate atomic clock signals anywhere on the planet..
Unless you have an atomic clock, which is synchronised with UTC (by some means without a time lag), GPS is the next best most accurate time signal we have access to, note the article stated that even Loran C and Omega transmitters were using GPS signals to control timing.... (GPS has generally replaced both of these systems with omega now being totally non-functional.)
Probably after all of that everyone will still think that they were right all along...
Last edited February 27, 2013 2:47 pm
You're welcome to believe what you like, but I've worked with GPS and other time sources (like the currently preferred source, the UTC atomic clock network) on a number of projects where precision and accuracy are of critical importance and I stand by what I said: GPS is not the current system of choice for the determination of precise and accurate time, and while it can be used incidentally for that purpose under certain conditions, it's not part of the system's objectives or purpose. Just like you can get out a tape measure to determine the distance between Sydney and Perth, you can use GPS for time if you want. Or, you can progress with the technology and use one of the easier, more accurate solutions available.
You're welcome to disagree, but I have no intention of getting into a prolonged argument with you, and I don't appreciate your penchant for pettiness and insults.
Edited to simplify and make a little more polite.
Last edited February 27, 2013 8:00 pm
Well said
I'm not sure where the author gets the idea that mainsprings counter inaccuracy and winding down is what the problem is. Springs drive the balance wheel's oscillation through the escapement, much the way a battery drives the quartz crystal's oscillation. It's the mechanical variation of each beat that results in inaccuracy. Generally speaking, the faster the beat, the smaller the error and quartz crystals in the kilohertz range are going to be much more accurate than mechanical watches in the hertz range.
Blah blah blah quartz crystal blah blah blah.
I can put my Omega watch (COSC certified chronometer http://en.wikipedia.org/wiki/Chronometer_watch#Officially_Certified_Chronometers) to my ear and hear the wondrous tick-tick-tick-tick of the movement. I can take it off and watch the movement though the glass back. Try doing that with a quartz watch.
And furthermore it keeps WAY BETTER time than my smartphone.
Sure it may cost 100x more than a watch from the petrol station, but a precision engineered chronometer is the ultimate gizmo. Not some piece of crap that's come out of some nameless Chinese or Taiwanese factory.
The next time you (or some you know/trust) is passing though Hong Kong. Get an Omega or Tudor for $1000-$2000. No need to spend $5K+ on that Rolex. It's hard to express the feeling that owning a REAL watch gives you.
I can see the merits of both sides. Some say a watch is a watch and others high end luxury watches are a work of art. It's like having a tiny universe working on your wrist just to give you the time.
As much as I love having access to every digital device out there, but sometimes the old ways are sometimes the best.
Thinly veiled "i can tell the time on an analogue watch"
Can't anyone over the age of 7?
Actually no. Growing up, my best friend's little sister (about 11 at the time) had no idea how to read an analogue clock. She'd grown up in the late 70's - early 80's when if you didn't have digital clock and watch, you were pretty much a no-one (refer to how Douglas Adams mentions digital watches in H2G2).
Ok, but she can read an analogue clock now right? I meant anyone who passed 7 years of age within the past 20 years or so. I remember learning how to read analogue clocks in early primary school.
Analogue readouts allow much quicker interpretation of what is being measured whether it be time, pressure, vacuum, speed or how full a tank is. The reason is; they not only tell you the measure on the readout, but can also provide visual feedback on the gap between where you are and where you should be.
If you've never heard of human factors engineering, go look it up.
Analogue readouts are just one of many tools to minimise human error and maximise ergonomics.
Give me an analog watch or speedo any day!
Elegant, simple, old school, artful and easy to read!
Last edited February 16, 2013 12:25 pm
True. I can. It even has Roman Numerals
Numerals? Who needs even those?
I'd like to know where you're getting an Omega Chronometer watch for $1 - 2k
It's all of there hurdles almost entirely being overcome that make a Rolex so amazing/attractive to purchase.
As Md pointed out below, this isn't Analogue Vs Digital. You can have an analogue watch with a quartz movement. The discussion is about the type of movement underlying the 'display'.
I call bullshit on this article. I've had plenty of cheap digital watches that kept terrible time.
I dont think accuracy means much to anyone, if i buy a $100k Rolex, it's more of a status symbol then a timekeeper.
Horologists and amateur horologists love the precision and intricacy of a mechanical watch. I agree that accuracy is important only to a point. A few seconds a week won't make any difference to anyone but bank robbers and CIA operatives.
I feel that Quartz watches are completely soulless. There's something about the beautifully complex engineering that imbues a mechanical watch with soul and character.
Reminds me of this:
Sherlock Holmes and Dr Watson go on a camping trip. After a good dinner and a bottle of wine, they retire for the night, and go to sleep. Some hours later, Holmes wakes up and nudges his faithful friend. “Watson, look up at the sky and tell me what you see.”
“I see millions and millions of stars, Holmes” replies Watson.
“And what do you deduce from that?”
Watson ponders for a minute. “Well, Astronomically, it tells me that there are millions of galaxies and potentially billions of planets. Astrologically, I observe that Saturn is in Leo. Horologically, I deduce that the time is approximately a quarter past three. Meteorologically, I suspect that we will have a beautiful day tomorrow. Theologically, I can see that God is all powerful, and that we are a small and insignificant part of the universe.
But what does it tell you, Holmes?”
Holmes sighs and is silent for a moment.
“Watson, you idiot!” he says. “Someone has stolen our tent!”
A quarter past three is adequately accurate!
I seem to recall adding a leap-second to the GPS clocks at work. Try doing that with a digital watch... can't do it? Then the seconds displayed are meaningless in terms of actual precision/accuracy.
On analog OR digital.
Quartz movement all the way, simply because the watch isn't some chunky mess on your wrist.
Quartz clocks lose/gain ~0.5s a day at room temp.
I have no idea were you got your source from but here is mine: http://tf.nist.gov/general/pdf/2276.pdf
Quartz crystal digital watches accuracy depends on the quality of the crystal. Cheap digital watches have cheap impure crystals or ones that aren't as accurately cut or calibrated, so don't always vibrate at exactly 32Hz. Temperature also makes a difference. The accuracy claim of 1 second in 30 years is a complete fallacy.
More info here:
http://www.thenakedscientists.com/forum/index.php?topic=41810.0
Anyway, I can't wait for my Pebble Watch!
For a good time, ring 1194
Your first point is indicative of a deep cultural malaise. While second point is wishfully thinking masquerading as opinion.
The last an ambiguously dressed lie