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Time to get moving

December 1, 2008

That’s the balance wheel of my granddad’s old pocket watch over there on the right.  If you look closely, you can see that it moved about fifteen degrees while the camera shutter was open.  But even though this example dates from the 1890’s, the innovation that a wheel working against spring tension can act like a pendulum dates back to the 1600’s.  Once the height of ultimate technology, they’re now charming antiques.

Timekeeping is one of those developments that are absolutely essential to the society we have built, but as a mature technology have faded into the background. My dad was quite fascinated with clocks – and guns, I believe for the same reason; that he simply enjoyed Very Clever Things.  When I was growing up I thought it was normal to see an antique clock movement submerged in a buzzing ultrasonic cleaner, in your dad’s study, and to have the S. LaRose catalogue lying around.

If you geek out on technology history, ‘Slobber and Spittle’ has a cool article,  up on three timekeeping technologies: the astronomical reference monument (of which a sundial would be an example), the water clock, the pendulum clock, and the atomic clock.  I say ‘three’ technologies because those last two are actually the same, only in an atomic clock, the pendulum is a cesium atom. 

…The ‘l’ in that equation stands for the length of the pendulum, and ‘g’ is the force of gravity. The bit on the right means that we’re assuming that the arc the pendulum travels is considerably less than a full circle. Pretty simple, isn’t it? Of course, nearly all materials that a pendulum could be made out of stretch or deform in some way under stress, and gravity isn’t the same everywhere, even on Earth. So pendulums can only be so accurate.

For real accuracy, you need an atomic clock…

To mark the passing of events

It’ll be interesting to see what comes of having functioning atomic clocks in more portable devices.  Somebody will figure out a clever way to use that accuracy.

h/t Dana

Categories: Uncategorized
  1. December 1, 2008 at 09:42 | #1

    When I was a kid I was also fascinated with clocks and watches. I used to take them a part and clean them and put them back together. I was particularly enamored with alarm clocks and radios. Sadly, I grew out of it. Probably something to do with the fact that my parents told me it was unladylike and that women couldn’t be watch repairmen. Ehh well. Nice trip down memory lane. Thanks.

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