**WARNING** this post may contain inane questions

I have this Miyota 9015-powered bronze watch that always ran damn near cosc specs, but seemingly out of nowhere started running 3-4 minutes fast per day. Hypothesis: it's been magnetized (I realise there might be other reasons for the balance spring coils to have stuck together, but I can't fix those myself so I thought I'd start here).

I've since ordered one of those Chinese watch demagnetizers, but while I wait for it to arrive, I've been pondering the cause. I don't live under power lines, don't work with MRI machines, don't own a microwave and the only speakers I use are the ones in my headphones. In any case, it's in my rotation and have never encountered this problem with other watches.

Now two things things make this watch stand out from the others in my rotation: (1) It's bronze, and (2) since I like to 'reset' the patination every few weeks, I polish the hell out of it.

My potentially inane questions are therefor:

1. Could it be that, because of some property of the material, bronze watches are more susceptible to becoming magnetised than stainless steel watches? Is SS more antimagnetic than bronze?

2. Is it possible that the frequent polishing builds up some sort of electrostatic charge that causes the watch to become magnetized?

 

Absolutely THE BEST opening line in any post of 2016.

 

Did you polish it with one of these?

 

Yes, on his workbench:




*If I were still able to do so, I'd be giving dialstatic a new custom avatar message of "Meep! Meep!' or similar.

 

man, I thought I had a good one in my thread but I’ll admit this one beats it.

 

Do you mean the one saying this is not another Speedmaster thread? Yes, not bad - but you lose technical points for the misspelling of "thread":

Certain a very NFW pictured in that thread though.

 

Are you aware that unless the "polishing machine" is powered by elbow grease or water wheel or steam, you are subjecting that one watch to a very strong magnetic field on a regular basis. Do you understand how electric motors spin? MAGNETISM x 3 on an up close and personal proximity!

 

Wait, what? Are you telling me my whole write-up was for nothing? I had a new avatar picked out an' everything!

 

Hmm. I've been doing some online research, and my question may have been slightly less inane than I suspected.

What I already knew, is that a static electric charge can be created whenever two 'suitable' surfaces contact and separate. When these two surfaces are making contact, electrons can move from one to the other (leaves an excess of positive charge on one and an equal negative charge on the other). When the surfaces stop making contact, they still keep this charge imbalance. It's the well-known rubbing-a-balloon-on-your-hair-and-sticking-it-to-the-ceiling effect.

What I didn't know, is the cause of all this. Apparently, one of the most common caused of this electron transfer is the so-called triboelectric effect, which occurs when one of the materials' atoms have relatively weakly bound electrons, while the other material's atoms have 'outer shells' with relatively few electrons. Apparently, one can use this property to (empirically) order different materials in a spectrum known as the 'triboelectric series' (see below). Materials high in the table are more positively charged, whereas materials low in the table are more negatively charged. If my understanding of this is correct, when a material lower in the series is rubbed with a material higher in the series, the lower material will become negatively charged while the higher material will become positively charged - more so when their distance in the table is greater.

I assume that polishing a steel watch with a cotton cloth will not result in a significant electrostatic charge: the two materials are adjacent in the table, and in any case both are right in the middle (no charge). Bronze, on the other hand (a copper alloy) appears lower in the table (negatively charged). If I rub it, as I do, with a nylon cloth (higher in the table, positively charged), an electrostatic charge could potentially build up on the bronze watch case's surface. In addition, I frequently wear wool sweaters whose (positively charged) sleeves rub on the bronze case all day.

I'm gonna try to build a homemade electroscope next weekend to see if I can indeed give the bronze watch case a measurable electrostatic charge. Now what I still don't know, is if such a charge can somehow affect the movement (e.g. effectively make the balance spring coils shorten by getting them to stick together - like the balloon on the wall perhaps), or if the metal case would simply shunt static electricity around the movement. I'd appreciate it if anyone with any physics schooling would chime in ;-)

 

not if they remove the movement. if they didnt it can

 

So let me see if I've understood this correctly. When the lower "material" is rubbed by the higher "material" the two "materials" will become charged, the magnitude of which being determined by their distance on the table.

And 3-4 minutes is too fast?

The list above ranges from human hands via silk to rubber.....

Are you sure you need a Physicist? Is this really about your watch?

Look up Dr Van de Graaff I hear he generates lots of good feedback but charges a lot.

 

Great question, and research, glad OP asked the brave question so that I feel little less silly for asking two follow up questions. Note please consider my comments that of a small child or labradoodle.

1 Does OP's watch have iron inner caseback?

2 What is the correct procedure to 'earth' the watch.

Ok so Ive built and submitted many a computer to be pat tested. Including my personal computer. So as to stay safe from a component and human safty point of view. IT people use anti static matts and the yellow wristbands with cord to earth themselves. Whenever they conduct work inside a machine with a powersupply, capcitors, chips and harddisks.

I'm not a physics major, but dialstaics research feels right from a gut perspective. We commonly accept that electrical cabling is copper. From a stand point of improved quality of conductivity we use gold and other alloys. Often found inside modern electronics like microchips to create circuits for electrons. The etching of silicon etc etc

Thanks
P



Sent from my D5803 using Tapatalk

 

The new avatar is pretty cool. @dsio or @Trev would have to do your custom avatar message.

 

wow this forum is cool.. you can tag people like twitter @dsio satisfied now its not 3 words anymore? lol

 

So if this is correct teenage boys would get stuck to the fridge everytime they came out of their rooms

 

Undeterred by ridicule, I bravely scienced on because science - like love - is a verb. Or maybe it's a noun. This isn't my first language and I can never tell those two apart.

In any case, I built a simple electroscope this morning: a device with which one can detect static electricity simply by moving a charged object close to the sphere on top of the jar. If an electrostatic charge is present, the two triangles inside the jar should move further apart the closer you hold a charged object.

I tested the device by combing my wife's hair with a plastic comb (and a hidden agenda). It works! Now all I need to do is wear my bronze watch under my wooden sweater sleeve all day, and I can check for the presence of a charge tonight.

 

I never knew you could magnatize bronze. I always thought it was anti-magnetic. Or am I yet again missing something important.

 

Yep made of copper and tin, two of the least magnetic metals