The Breitling Watch Source Forums

I decided to put together a little primer on the electromagnetic spectrum and magnetism because I’ve seen a few posts around the forum about exactly what can and cannot magnetize your watch. Despite what my current avatar and signature might suggest, I am no Albert Einstein. I am just looking to make a few distinctions about commonly confused elements in physics and maybe dispel a myth or two. I’ve had the “pleasure”, as others on this forum have, to have been through too much physics education in college. I tutored the subject while a senior and also currently teach basic science education to elementary school students on a volunteer basis. If that doesn’t qualify me to give a lesson to you lot, then I don’t know what does! Only kidding! Please feel free to correct, reprimand, and add to this post! I am not the end-all, be-all on this subject.

For those who are unaware, when a watch becomes magnetized it is primarily the hairspring which is affected (guys, correct me if I'm wrong). The hairspring, when magnetized, functions improperly. Instead of freely coiling and re-coiling, there is a magnetic attraction that occurs, effectively tightening the hairspring and thereby shortening the period of the timepiece. This, in turn, dramatically increases the rate of the watch. As I’ve read here, on the order of minutes-per-hour fast. The only way to “magnet-proof” a watch is to completely remove any component that is susceptible to magnetic field.

So, off to the physics races!

What’s in a name?
There are two main concepts that I’ve seen most often purported as the culprit behind watch magnetization:

1) Components of the “Electromagnetic Spectrum”
2) Magnetism and electromagnetism.

Despite their name both involving some form of the word “magnet” there is very little in common with these two concepts. I will describe this a bit further as I go along, but if there is one thing you can garner from this post, it’s that no component of the electromagnetic spectrum is responsible for magnetizing your watch. It is only relatively strong magnetic fields in close proximity to your watch that can result in a magnetized movement.

What is the Electromagnetic Spectrum?

The electromagnetic (EM) spectrum is merely a map of known levels of radiation, ordered by wavelength (size). Radiation is a general term here which describes the wave form of energy emitted by celestial bodies, radioactive material, and other energy sources. Below is an example of the EM spectrum taken from Wikipedia.

http://upload.wikimedia.org/wikipedia/c ... s_edit.svg

The EM spectrum is ordered from the biggest, lowest energy waves (left), to the smallest, highest energy waves (right). You will certainly recognize a fair bit of the categories: microwaves, radio waves, visible light. We are literally bombarded by billions and billions of these waves in a day (please don’t call me Cark. Sagan). Almost all communication and detection devices employed today use some small sliver of the EM spectrum. This includes almost every medical and security scanning devices aside from Magnetic Resonance Imaging (MRI).

While certain portions (generally, the higher energy region) of the spectrum can have disastrous health affects and can literally disintegrate matter, there is no mechanism by which these waves can produce a magnetic field. Your watch, with respect to magnetism, is unaffected by the EM spectrum.

Magnetism and Electromagnetism

Types:
Magnetic objects come in three basic flavors:

1) Permanent Magnets
2) Temporary Magnets
3) Electromagnets

All of these pose a significant risk to your watch because they can be of sufficient strength to magnetize the internals of the movement. If you allow your watch to get close enough to any one of these you might be in trouble.

Essentially all three types rely on the alignment of negative and positive regions of an atom to create a magnetic effect. It has specifically to do with electron spin but for purposes of illustration, I’ve shown picture of a simplified magnet. A magnet is born when all of the positive and negative regions line up.



Some materials have regions of positive and negative charge lined up inherently. These materials are called permanent magnets. These magnets will not lose their magnetism without a fight. These are the ones found most commonly around the house as refrigerator magnets and in consumer electronic devices. These magnets are an integral part of speakers of any size, hard drives, etc. They pose a real risk to your watch.

Materials, like soft steel, can be turned into temporary magnets by aligning the positive and negative regions. If you’ve ever run a magnet over a paper clip repeatedly, you’ve created a temporary magnet. Because their normal configuration is non-magnetic, it doesn’t take much to return these to their non-magnetic state. This type of magnet can still pose a risk to your watch because, when aligned, can still be fairly strong.

Finally, the most interesting type of magnet, IMO, is the electromagnet. This is a magnetic field which is induced by the application of current through a coil of metal wrapped around an iron core. The flow of electricity actually artificially aligns the positive and negative regions in the material and induces a magnetic field. This phenomenon is used in conjunction with permanent magnets to generate electricity as well as serve a means to create efficient electric motors. These magnets can become very powerful as they are limited only by the current applied to the coil itself. As another user posted noted here: http://www.breitlingsource.com/phpBB2/viewtopic.php?f=6&t=16460

Walking into a room with a generator in it is a big no-no for your watch.

Magnets all have fields associated with them. One of the best ways to visualize those fields is by use of iron filings. Here is a picture from Wikipedia of just such an illustration.



Proximity:

How close you can get to a magnet depends on its strength. The closer you get to a magnet, the more intense the field strength becomes. As a general rule I’d suggest not placing your watch directly on or directly next to anything you might suspect is magnetic. Just moving 6 inches away from a relatively strong magnet can dissipate real risks of watch magnetization. The field strength increase when you approach the source is exponential.

Metal Detectors:

I’d like to just say a final word about the use of metal detectors and how it might affect your watch. Most metal detectors use an oscillatory generator to produce very short, alternating magnetic fields which are used to detect magnetic metals. Even more advanced designs which can use more severe magnetic energy don’t pose a significant risk to your watch. The alternation of field direction and relative weakness mean that there is little chance your watch will become magnetized. I wouldn’t suggest you try it, but the occasional swipe at a sporting event/airport won’t hurt.


If you've made it to the end of this, I apologize for the length! I never intend for these to get so out of hand but sometimes I just can't help myself. I hope this helps answer more questions than it poses in your mind.

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“The only reason for time is so that everything doesn't happen at once.” - Albert Einstein

Ian, thank you so much for that - incredibly informative and very accessible to a dunce like me!

You are absolutely correct on the watch front about the hairspring. Other parts of a watch can become magnetised, but the impact is negligible to none. The hairspring is a problem because it controls the regulation and also I believe that it's extreme thinness makes it more susceptible to becoming magnetised than (say) a screw or a wheel.

wow

Thanks for the refreasher. I used to know some of this stuff a long time ago when in college. Funny how little of it I retained!

Funny how I can still remember the correct technique to do a propor keg stand

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SA Blue Dial Silver Subs Pro 2

Wow what a great post

I had no idea my Navitimer would be susceptible to this problem when I bought it.

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Great post. Thanks for taking time to explain this.

-Craig

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Chronomat 01- Sierra Silver/Steel
Navitimer 01- Limited Edition #1337/2000

Physics 101, i loved that class (way more than biology or chem).

You still won't see a cell affecting your watch (related to the other thread).

Now bigger magnets, sure... heck if some can fubard electronics, i'm sure they can fubard something mechanical.

Now anyone wanna try 'Is a swiss watch microwable?'

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Panerai PAM212 | Panerai Diver Strap
Panerai PAM111 | Black Croc Strap
Omega Planet Ocean | SS Bracelet
Rolex Submariner | SS Bracelet (Sold, Awaiting Funds)
Breitling Navitimer Olympus | Brown Croc Strap (Arriving)

Thanks so much. Superb post with very good info.

I don't often do this, but I absolutely hate misinformation and as Ian has gone to so much trouble to make this a wonderful thread I can't stand back. So, with apologies in advance for any patronising tone........

I know that you have just turned 23 and make an undoubtedly good living, but.......

I have been studying watches since you were in kindergarten, am learning watchmaking (which requires an understanding of dealing with magnetism) and have studied pretty much all of the modern and vintage classics on watches, movements, repairing and adjusting - from Breguet to De Carle to Daniels.

Additionally, Ian is clearly extremely knowledgeable on magnetism as evidenced by his extremely educational post at the start of this thread.

As Ian states, permanent magnets are found in speakers of any size and pose a real risk to your watch.

Cell phones contain speakers and they have magnets in them - that's an indisputable fact.

Magnets can affect watches - that's an indidputable fact.

The risk of a watch being magnetised by the relatively weak fields is clearly less than throwing your watch into an MRI machine, but that risk clearly exists - to say that it doesn't is simply untrue.

The risk can be virtually eliminated by not storing your watch on top of the cell phone, and of course putting your watch on your cell phone for a few minutes once is unlikely to cause problems. However, to say that cell phones cannot magnetise your watch is simply untrue. People these days often keep their cell phone next to the bed - same as their watch, and keeping the two separate is a sensible precaution to avoid any risk.

You should try disassembling a cell phone. The magnet inside the speaker is so tiny you can barely see it. I doubt very much you can magnetize a hairspring through it. I too hate misinformation. I'm the same age as you and I've been taking things apart since we were both in kindergarten. I've seen speakers with magnets large enough to pick up a heavy wrench. The speaker in a cell phone is smaller than a dime. I just tried picking up iron filings with it and I couldn't.

I'll post a picture of a cell phone speaker. You could do the math based on the size and figure out how many Gauss a magnet that size can put out. My guess is that it is tiny.

Fine.

Whatever you say Dan.

Clearly I don't know what I'm talking about, that's evidenced multiple times all over this forum.

Ian, apologies for the direction that I seem to have taken this in, your article is exceptional.

Ahh, the old, "I'll take my ball and go home" game. Classic bully behavior. Just because you've posted a lot of correct information here, it doesn't mean you're right about everything. There's no need to be insulting and dismissive when you're challenged.

The fact remains that the cell phone speaker I'm holding in my hand has a very small magnet. Additionally, it appears to have some shielding, perhaps so it doesn't disrupt the electronics in the phone. Luckily, I work with people who design cell phones, so I can ask them on Monday.

It is sad that instead of being interested in finding out whether your hypothesis is true or not, you choose to walk away instead of digging deeper into the science. I for one would like to know if cell phones are really a problem or not. I doubt MythBusters would take this one on.

NOT really sure how this thread turned into an argument... Not upset about it, just surprised.

Point of the post was to just clear up what can and cannot serve as a source of magnetism. Magnets in a speaker, obviously, can be such a source. The likelihood that they could magnetize a watch depends on too many things to make a categorical statement one way or the other.

Only way to know for sure is through a controlled series of experiments, but that's just the scientist in me. Anecdotal evidence is the worst kind for drawing any meaningful conclusion.

I would say, that if you could avoid it, keep you watch off of your phone. Always err on the side of safety. There are obviously arguments that designers of cell phones have taken into account these issues already by the use of shielding, or using weak magnets but why risk it?

Can we play nice now?

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“The only reason for time is so that everything doesn't happen at once.” - Albert Einstein

So pondered this for a couple of hours - knee jerk posts and all that.

If the perspective is that I am a bully, then I'm surprised, but I can't control what others think so I'm not going to worry about it.

As I have said before I don't understand the finer points of magnetism, and can't offer fact based logic around short term exposure vs. prolonged exposure etc.

However, let me try just one more time......

The hairspring of a watch is incredibly fine which makes it susceptible to magnetism. It is generally made of magnetism resistant materials these days, but generally not magnetism proof. Cases also protect to some degree, but that's no guarantee and different cases offed different degrees of exposure - a DB vs. a solid back, etc

Cell phones contain magnets and magnets are dangerous to watches.

I cannot provide scientific facts of what percentage of watches will become magnetised to what extent after exposure to a cellphone through sitting on / in very close proximity on a nightstand or similar, or how long it would take for the magnetism to become evident. I also don't know which cell phones offer the most / least risk (whether older phones are worse, phones with a speakerphone option are worse, etc).

The solution would seem to be simple - don't keep your watch next to your cell phone.

My last post in this thread, which incidentally was written before Ian's last post above, he just posted before me.

Not jumping into the argument here but I thought this was an interesting statement made by Administration in the models section of BS website under Avenger Seawolf Chrono:

Description
This model features Breitling's proprietary magnetic pushpeices. These special pushpeices allow use of the Chronograph underwater without fear of letting water into the watch. This feature requires that the watch be quartz as the magnets would affect mechanical timepeices.
http://www.breitlingsource.com/watch_de ... e_182.html

I don't have a clue how powerful the magnets for the pushpieces are but I wouldn't think they were very strong. ( I realize that magnets and their strength is not only related to size but also to the magnets basic material as well.)

Just a thought guys.

Likewise, not jumping in (since I know next to naught of watches). But this is interesting discussion. Might Shadow & dhalem be referring to the VOICE speaker magnets which r tiny, and Roff perhaps referring to the RINGER speaker which by necessity is LOUD & presumably much more powerful (at least when ringing)?

Someone should convince Bonedoc to do another testing, this time w cellphones...