Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Tigerkix on 17/09/2009 17:03:26
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Was the conception of the second after we found out that quartz vibrates once per second? or was this unit of time used before we found that out?
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The ancient Egyptians divided the day into two x 12 hour parts. They used what could be described as the forerunner of the sundial to measure the 12 hours of day and a water clock to measure the 12 hours of night. These hours were not of a fixed time, but depended on the seasons. It was not until Ptolemy (around 150AD), that these two 12 hour parts were put together into one 24 hour day, with each hour being the same length of time.
But it was the Babylonians, around 450 yrs before Ptolemy, who first divided a double hour into 60 sub sections, and then again, and again and on to 6 places.
So I suppose you could say the second was first used by the Babylonians, but was given its value (as we know it today, pretty much) by Ptolemy.
I rather doubt that any of these knew anything about the vibration of quartz. My personal feeling, is that it is just a 1 in a trillion spot of good luck for the worlds chronologists that quartz fits nicely with time.
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"quartz vibrates once per second"
It doesn't.
the quartz crystal in a typical watch vibrates 32768 times a second, but only because they cut it to the right shape and size to make it vibrate at that frequency.
You can get a quartz oscillator to work at just about any frequency inthe same way that you can make a tuning fork from steel for just about any frequency- lower frequency ones are bigger.
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Thx guys There is so much information about just a second. And i guess there are many many other uses for quartz other than just clocks and watches. You guys are AWESOME
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