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Plot and as with

Best fit to data (blue line). Reference gradient (red lines):-583ms/day/mrad.
Going will vary with amplitude because sin(θ) ≉ θ

Comments (see all | edit)

19 May 2009 [15:44]
Another curiosity is that small changes of Going vs Amplitude [link] shows a positive slope - not sure why. And there seem to be clusters - as if behaviour changes quickly and sits still for a while. The normal physics of a pendulum [link] predicts a negative slope, as here [link] so there is something more subtle going on. Maybe the spider again?
19 May 2009 [14:58]
Just a general remark, it has been noticeable over the last few days that pendulum amplitude forms a nice linear relationship with air density. This fits perfectly with a 0.5*rho*V^2 drag law. see [link]
19 May 2009 [12:05]
clock wound at 1.05pm - note the small glitch in amplitude, perhaps opening the clock case causes air currents that causing a small change in pendulum motion. Or maybe the act of winding moves the clock bed slightly causing the pendulum to be disturbed.
17 May 2009 [00:00]
... and why has it suddenly changed back at midnight? There is no change in anything else - some physics not accounted for here!
14 May 2009 [23:30]
What caused this gradual change in going, over 8 hours before and after midnight?
12 May 2009 [12:05]
clock wound at 1.05pm. temp is stable and going seems to be spot on zero. Might this last until October now?

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Interval between data points: seconds [either 3 seconds (weather data is duplicated) or multiples of 60 seconds (all data is averaged)].

Contact:, Trinity College, Cambridge