Sunday, 15 April 2012

...How Time Used to be Kept.

We all know that back in the day the sundial was the go to clock for most people. It was consistent, accurate, and reliable. Learning about sundials when I was a kid I always used to wonder how they would keep time on a cloudy day? I just assumed that they didn't, but I should have given them more credit.

The sun is never around when you need it.
Water clocks were the big seller and the Persians along with the Ancient Greek and Romans used them. You would poke a hole in a bag or bowl, fill it with a set amount of water, and when it ran out time was up! Plato even invented an water alarm clock. Any water that fell out of the bag would fill up a tub below it. A small bowl with steel balls would float to the top and as the balls spilled out they would hit a copper plate making all sorts of racket. Another version of the water clock worked almost in the opposite fashion. A small bowl with a hole in the bottom would be placed in a tub of water and slowly fill up. Once it was full your round of  Scategories was over. My favourite was how the Chinese would do it. They would light incense sticks of different scents throughout the day of a certain length that would burn for a set amount of time. People could then tell what time it was just by the smell.

It smells like Jasmine o'clock.
Of course Hourglasses were eventually used, but they were rare as glass working was difficult to do for a long period of time. Once glass blowing was fine tuned, the pendulum clock had already started to make its appearance. Here, someone figured out that a coiled wire or spring took a set amount of time to uncoil. Attach it to a few gears and winches and you were set. Today we generally use atomic clocks where a radio active material emits it's protons or electrons or whatever trons they want. And so you know, a second is traditionally defined as 1/86,400 of the earth's rotation. Officially its: 'the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom'.

So much easier than an hourglass
And that is what I learned today.

-Canada has a glow in the dark quater that'll set you back $30.

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