IIRC, automobile driver's stopping distance includes 200 msec to process the need to stop. Our wetware is not particularly fast.
Bill Hawkins -----Original Message----- From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Chris Albertson Sent: Saturday, April 18, 2015 12:51 AM To: t...@patoka.org; Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Visual clock comparison It would be an easy experiment to get two analog clocks and put them side by side. You would not even have to set them to the "true" time, just to each other. Let one run slower and wait until you can see a difference. Clocks on a computer screen are different because the screen is refreshed one order of about 100 times per second. They move in jumps, not continuously. Ears are better than eyes at this. If you choose the "right" tick sound. The best one sounds like a drummer hitting the metal rim of his drum to make a "click" sound. Some people can hear if two clicks are just a few milliseconds apart or not. Beware of the speed of sound. It is very slow, about 1 milli sec per foot of distance. You clocks must be very close to each other or the delays will be different. On Fri, Apr 17, 2015 at 11:16 AM, d0ct0r <t...@patoka.org> wrote: > > Hello, Netizens ! > > I am wandering what is the average human ability to visually compare two > clocks ? Let say I have XClock application running on one machine (stratum 1 > NTP) and I have my project clock close by. And I would like to match the > reading. If I'll see the difference, which range it will be ? 100ms or so ? > I also tried to use my ears (CHU radio signals and clock display, NRC phone > line). However NRC "Talking Clock" could be routed via Satelite which will > compromise the "reading" a little bit. Thanks ! > > -- > WBW, > > V.P. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.