Could a magnetic bracelet cause a watch to lose time?
Discussion
A few months ago the OH’s Skagen quartz watch started to lose time. She had the battery changed but it continued to lose time so she assumed there was another fault. After finding out what it would cost to have it serviced, which might not actually solve the problem, she decided it would be less risky to buy a new one – She bought another Skagen (albeit a different model) as she loves the design. Almost immediately this one started to lose time too. She wears a magnetic bracelet on the other arm and, looking back, she bought this at roughly the same time that the first watch started to lose time. Could this be the culprit? It was certainly powerful enough to interfere with a compass that I was holding while standing next to her one day – could it affect a watch too?
I'm assuming these are quartz watches with analogue displays.
I think the basic answer is technically yes, but under such specific circumstances that the practical answer is no.
The watch motor works via a tiny magnetic field. That field will be additive to any static external field (unless the material conducting that magnetic field has saturated).
There are two wasy of disrupting the motor.
1/ The external magnetic field must be strong enough to saturate the magnetic flux in the motor's field - so much magnetic force is presnet in the magnetized material that the extra magnetising force from the watch coil can not change the magnetic flux present. The watch won't tick.
Magnetic flux density is inversely proportional to distance from the magnetising source. I'd be surprised if a wrist sized permanent magnet would be powerfull enough to saturate the coil material if placed on top of the watch, let alone from the opposing wrist.
2/ Moving the permanent magnet past the watch as it's ticking could could cause a rate of change of flux that exactly opposes the field that established by the coil, causing a cancellation of the flux and stopping the motor from ticking. One in a billion chance of lining up the magnet and swiping past at exactly the right speed and time I reckon.
Does beg the question why anyone would want to wear a magnet though. I mean it won't do you any harm, but neither would a banana skin perched on your bonce and you don't see people doing that.
I think the basic answer is technically yes, but under such specific circumstances that the practical answer is no.
The watch motor works via a tiny magnetic field. That field will be additive to any static external field (unless the material conducting that magnetic field has saturated).
There are two wasy of disrupting the motor.
1/ The external magnetic field must be strong enough to saturate the magnetic flux in the motor's field - so much magnetic force is presnet in the magnetized material that the extra magnetising force from the watch coil can not change the magnetic flux present. The watch won't tick.
Magnetic flux density is inversely proportional to distance from the magnetising source. I'd be surprised if a wrist sized permanent magnet would be powerfull enough to saturate the coil material if placed on top of the watch, let alone from the opposing wrist.
2/ Moving the permanent magnet past the watch as it's ticking could could cause a rate of change of flux that exactly opposes the field that established by the coil, causing a cancellation of the flux and stopping the motor from ticking. One in a billion chance of lining up the magnet and swiping past at exactly the right speed and time I reckon.
Does beg the question why anyone would want to wear a magnet though. I mean it won't do you any harm, but neither would a banana skin perched on your bonce and you don't see people doing that.
Thanks for the replies. Since dispensing with the magnetic bracelet her new watch has kept perfect time. Also, her old watch has been sat in its box for nearly two weeks. We took it out last night. Guess what! It’s kept perfect time. So, however unlikely it may be that the magnetic bracelet has caused the problem, it does appear that this is the culprit. Her theory, which I concur with, is that the disruption has occurred overnight while she has been sleeping. She usually keeps both on in bed and tends to sleep on her side with both wrists fairly close together and the magnets in the bracelet do seem to be quite powerful. She also remembers that she usually noticed that her watch had lost time when waking up on a morning, so we’re pretty sure we’ve solved it.
mikeveal said:
Does beg the question why anyone would want to wear a magnet though.
It's one of those 'new age' things that's supposed to have health benefits. As she’s tall, slim, blonde, pretty, a great friend (and more) and loves her cars, I’ll allow her that one vice Edited by MitchT on Friday 19th August 11:40
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