[time-nuts] NPR story on coupled pendulums

Bill Beam wbeam at gci.net
Wed Jul 29 19:22:39 EDT 2015


These University Of Lisbon "Scientists" have rediscovered a very old wheel.

Old physics:  Two coupled nearly identical harmonic oscillators have two stable states.
They will operate with relative phase = zero or 180deg. How they are coupled is not
an issue; they only need to be able to transfer energy one to the other.

Regards

On Wed, 29 Jul 2015 13:44:19 -0500, Bill Hawkins wrote:

>They talk about sound pulses affecting the pendulums.

>Sounds more likely that the mechanical vibration transmitted through the
>aluminum bar affects the escapements.

>Perhaps the 'tock' side generates the strongest pulse, and the 'tick'
>side is sensitive enough to be affected by that pulse.

>That would soon have the clocks synchronized out of phase, provided the
>mounting arrangement did not absorb too much of the pulse energy.

>The situation is similar to synchronizing a TV vertical oscillator
>(running a bit slow) with the received sync pulse from the broadcast
>station, no?

>Bill Hawkins


>-----Original Message-----
>From: time-nuts [mailto:time-nuts-bounces at febo.com] On Behalf Of Hal
>Murray
>Sent: Tuesday, July 28, 2015 10:55 PM
>To: time-nuts at febo.com
>Cc: Hal Murray
>Subject: [time-nuts] NPR story on coupled pendulums

>University Of Lisbon Scientists Solve Pendulum Clock Mystery

>Two professors at the University of Lisbon say they have discovered why
>the pendulums of clocks set on the same surface will eventually swing
>together in opposing directions.

>http://www.npr.org/2015/07/28/427178282/university-of-lisbon-scientists-
>solve-
>pendulum-clock-mystery

>I thought the NPR story was not very interesting.  (But it probably
>wasn't targeted at time-nuts. :)

>----------

>Here is the paper:
>  Huygens synchronization of two clocks
>  http://www.nature.com/srep/2015/150723/srep11548/full/srep11548.html


>--
>These are my opinions.  I hate spam.



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Bill Beam
NL7F





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