* Magnetism, Have We Missed Out The Obvious? Laptop-Users Be Aware!

 By: Kong : January 26th, 2008-10:33

Upon reading the thread about Magnetism Effect from Watch-Winder "Navel Gazing - A Question for Watchmakers and Engineers..." by Harry Tan, I suddenly remembered there is a question I've always wanted to share and ask. 

The little experiments and photos were taken in April 2007, and had forgotten all about it.

I'm a notebook-user, and I've sent 2 watches for abnormal daily rate getting faster without placing my watches near mobile, speakers or even bags with the magnetic clips! 

There is only one thing I use daily and many hours with it..... my notebook (or laptop)!

Coincidentally, I was trying to find some answers and was reading Donald de Carle's Practical Watch Repairing...and there was a chapter on magnetism ( I've enclose a page of it for your reference, and also for the respect of copyrights).

Since magnetism is something we cannot see, how are we going to quantify?

Donald's answer was simple....use a compass.  Logical. 

"Like poles repel, opposite poles attracts."


Agreed with John's ( Ei8htohms) and Mycroft's inputs :

" magnetic field strength drops off as the square of the distance from the source, so every centimeter of separation is dramatically safer for the watch in question."

"The effect of magnetism varies inversely to the square of the distance from the source of magnetism. Therefore when you move a watch away to twice the distance, the effect lessens by 4 times."

However, I believe the time the object expose to the magnetic field has direct impact too.

So that's how the little experiments began ............


First thing, how many of us realise that our wrists are directly on top of the notebooks?

Regardless of brands, it is only logical to place the speakers at the front of the notebooks (directly below the hand-resting areas).

I've used 2 brands to demonstrate the effects and I've tested both sides of the notebooks.

Let the pictures do the talking .................

Figure 1 : For the right-side of this brand, the compass-pointer (marked GREEN ) did not deflect much till it was directly above the speaker area.  The compass-pointer deflected about 180 degrees.

Figure 2 : For the left, the magnetic effect was much stronger.  About 3 cm away from the Right-speaker, the green-pointer deflected as much as 280 degrees!

Figure 3:  Tried on another popular brand of notebook, the effect was visible.  When it was on top of the speaker, the green-pointer deflected by about 270 degrees too.


NOW the question:  So how does it affect the watch on my wrist?

Perhaps Figure 4 may shade some light. 

Figure 4 :  I simulated the watch using a compass instead.  Based on one of the brands (notebook), the pictures on top showed my hands away from the notebook (at least by 10cm or 100mm).  The compass-pointer has no response.   As I placed my hands on top of the notebook-resting-pads, observed the compass-green-pointer deflected.

For the left-hand side, the deflection is near to 180 degrees  while for the right-hand side it was about 90 degrees. 

One more observation...what will happen to the watch on either my wrist at these two positions for at least 2 hours at a stretch?I don't know.  

Since I removed my watches when working long hours (continuously) , they have been behaving well  smile

For your thoughts over the weekend, may save you some monies.




A good reference from the book " Practical Watch Repairing" ... abour Magnetism. Enjoy!

added to Editor's Pick

This message has been edited by AnthonyTsai on 2008-01-26 20:13:01 This message has been edited by Kong on 2008-01-27 09:26:57

I am keeping my watches

 By: Bill : January 26th, 2008-10:42
But throwing out my lap top.  LOL.

Only kidding.

Lucky for me I am right handed so I don't have to worry about cell phone magnetism.

Thanks Kong for the great report and the bad news.


thanks Kong. i spend a lot of the day using my laptop and

 By: G99 : January 26th, 2008-12:35

wearing 2 watches i am willing to accept time gain or loss although i havent actually noticed any. but does it do any damage to the watches themselves?


most of the time it's easily fixed

 By: Chromatic Fugue : January 26th, 2008-13:36
Two of my watches became magnetized over the past few months, and I suspect my blackberry.  Luckily, any jewelry store with a watchmaker can demagnetize a watch in a matter of seconds without opening the case.  

I knew that there was a practical aspect...

 By: Tony C. : January 26th, 2008-14:21
to my collecting vintage IWC Ingenieurs! Thanks for the interesting post.

Tony C.

Kong,good experiment and reminder!

 By: BHK9 : January 26th, 2008-19:06

Hi Kong,

Thanks many would be thankfull to you on all the experiments,articles and advice.

Many would really over look on the effect on lap top and their speakers!Thanks.

Tony p,this post will help iwc sells more,especially ingenuir.LOLOL.....


I guessed if the distance is too near to the magnetic field, doubt...

 By: Kong : January 27th, 2008-10:25

the soft-iron case would be able to withstand.  I also think the exposure time play a part too.

Do re-read John's ( ei8htohms) post, his friend's watch has a soft-iron case!

I would say be mindful and take precaution, though many would disagree and purchase a demagnetiser smile.



Kong, useful information. Thanks

 By: ling5hk : January 26th, 2008-19:18

Apart from laptop, handphone also has very strong magnetic field.  I haven't done any experiment.  Don't know how actually it will affect the watch when you hold your handphone with the same hand.



Knows the source of the magnetism & avoid close proximity...

 By: Kong : January 27th, 2008-10:19

The distance between the handphone and the phone is far, so has no effect, except when placed your watch side-by-side with your handphone.  The strongest magnetic field is at the earpiece  (the speaker)!

I believe in taking precaution.... a few of our friends mentioned their watches are still fine... well, its a matter of when smile

Previously when I reached home, last time, I placed my mobilephone on top of my wallet.  A long while no issue, till one day, my credit-cards in my wallet could not 'swipe through'.  Now the mobile is away from my watches and wallet!  Not taking any chances.

OK, since you asked, I tried to show you the evidents of the mobilephone.


Notice the compass GREEN needle did not move at all with and without the mobilephone.

  1. The setup is simple, the compass will represent the watch location.
  2. I hold the mobile to my ear as I normally do when using it.  This will provide the actual position of the phone on my hand.
  3. And then I laid my hand down as shown above with the phone.  I placed the compass on my wrist. Align it to a fix position on the compass for the GREEN needle. Take a shot...(this was difficult...need balancing!)
  4. Remove the mobile. Take a shot (with same difficulty).
  5. Compare the 2 pictures.
  6. Results -  Needle DID NOT deflect at all. Perhaps it only applies my N95 smile





Thanks for the experiment, Kong

 By: ling5hk : January 27th, 2008-15:46

Err... A friend of mine even told me not to put handphone in the pocket. The close proximity will affect your little john's performance.  This one I think there is no basis. 

In fact, it is wise to keep a distance between our watches and any electronic and electrical goods even though you watches are anti-magnetic.




Very interesting post Kong!

 By: AnthonyTsai : January 26th, 2008-20:16

Now we someone to test this with all different laptop brands to see there is any laptop which is "horologically approved" :P


great stuff, thanks! (nt)

 By: ei8htohms : January 26th, 2008-21:32


Thanks, Kong,

 By: masterspiece : January 26th, 2008-22:11
for that great experiment. Good thing I use a desktop computer!smile


Great post Kong

 By: waien : January 26th, 2008-23:01
Gotta be more careful now with wearing my watches when working on the notebooks. I guess I've been quite lucky as I have been using notebooks for many many years and have not detect any of my watches running faster.


Looks like some will end up investing in demagnetisers! :-)...

 By: Horolographer : January 26th, 2008-23:11

Thanks Kong for this interesting experiment. In an increasingly wired society, we clearly forget that everywhere around us there are fields of magnetism. I use laptops regularly - but fortunately they spend most of their time in docking stations at home or office. But unconciously I take off my watches anyway to stop them from scratching on the surface of the notebooks anyway. Thank goodness.

This makes me think about all the different things we do that exposes us. Like my wife using her hairdryer?

BTW - the distance of the compass from the top of the wrist to the surface of the keybard on the PC is further than the motor of a small watch winder from the watch. May be you could try out the compass experiment on a watch winder?





thanks Kong.....means u need to buy a watch with a soft iron core. LOL!

 By: decksurgeon : January 27th, 2008-01:47

Doubt so...a soft iron cage also has 'weak points' like....

 By: Kong : January 27th, 2008-10:29

the date-window, the hole/s of the hands (hr, min, sec) and the crown. 

It depends on the strength of the magnetic source smile

So prevention is better.



Not so sure about that.

 By: tony p : January 27th, 2008-23:10
I think the soft iron inner casing acts as a Faraday cage. I thought that these are effective at excluding magnetic fields even when they have holes in them (eg aeroplanes with windows). Or is it only electric current?

However, magnetic flux and electric current tend to go hand-in-hand, so I think having holes in the iron inner casing of an "anti-magnetic" watch would not compromise its function.

Tony P

Great post. Some more food for thought...

 By: Rez : January 27th, 2008-04:37
After reading this post it occured to me that since hard drives should be the component in laptops that have the most powerful magnet, that we may have stumbled upon another reason to see the new SSDs (Solid State Drives) as attractive. Prices on SSDs are set to become more and more reasonable, so for watch enthusiasts / collectors we might have found another reason why they might be worth considering.

IT would be intersting if someone with a SSD laptop could arrange some kind of comparison.

Hmmm . . . some of my favorite watches are . . .

 By: Dr No : January 27th, 2008-08:48

. . . the Ingenieur, Milgauss, and Railmaster, both vintage and modern . . . I thought it was primarily for aesthetic reasons, but perhaps there was a magnetic subtext as well . . . curiously, Art

My guess is the vintage pieces should be more ...

 By: Kong : January 27th, 2008-10:36

susceptible to 'easier' magnetisation due to the materials used to make the hairspring.  Just my guess.

Perhaps the newer movements, with different alloys and without iron content for the hairspring , it could be of better resistance to being easily magnetised.

This is a very interesting topic to investigate further.  Hopefully one of the manufacturers could share with us....or Bernard could have captured some details during his IWC factory visit.


PS : Also keen to find out if the manufacturers also test their watches with induction cooker smile .

No wonder my laptop and cellphone time has been off

 By: Jokoh : January 27th, 2008-19:23

Maybe of we put a magnet in the watch than the negative impact would be nullified ;-)

hehehe...LOL....MONDAY BLUES!!

THANKS Kong.....interesting thought ;-)





Thanks, Kong, great detective work!

 By: ThomasM : January 27th, 2008-20:43

I'm particularly sensitive to magnetic fields, and get a headache just from using cell phones - a bona fide, wave pressure migraine just from having an active cell phone operating near my head/ears.

But it is a good idea to note that EMI and RFI are related but different, and that a cell phone in send mode vs receive mode have differing levels of both (EMI and RFI)


Thanks for an "eye opening" post!


I will note that as someone who is an early adoptor of both (my first cell phone was the military style "shoulder field kits" and I've used them regularly since...) I've never had a problem with magnetized watches.

Of course, I may not have as much experience with watches as some others...


Oh, and my laptop speakers are at the top, near the screen hinge, not at the palm rest, bottom, of my Toshiba.




TM, so your brand of PC is approved for WIS ? :-)

 By: Kong : January 29th, 2008-11:48

 TM, so your brand of PC is approved for WIS  smile

Likewise, I will headache if too long on the now use a cable-mouthpiece. Likely due to the RF (microwave).  Can't prove it though.

Typically when you dialing out from your mobile, the power of the RF is the highest to ensure connection.  What make it worse is the distance between you and the station.  The nearer you are to the station, the lesser power of RF will be your phone battery also last longer.  The mobilephone will adjust the power automatically to ensure good connection.

You are right though you are the early adopter, you still have not encountered issues with your watch. The reason is simple.The magnetic components (the earpiece and the mic) are quite a distance from your watch (wrist).  The only time when the distance could be near is when many localised their wallets, keys and watches at a single location and extremely close to each other.  That where the chance of watch being magnetised is the highest!

Indeed it is good you brought up EMI & RFI, they are magnetic waves and not magnetic field.

As one of the forummers (zephyr49)  also mentioned, he works in the Air Traffic Control Centre, and his watches are fine.  No doubt about it, as communication machines generate EMI/RFI waves....but if he works in a MRI room, that will be different story.

An antimagnetic soft iron cage will not be able to defend itself if too near to the magnetic field (source)... even the IWC test also showed possible "hotspots".

Great, the Toshiba has the speakers at the hinge areas.... now the question is where is your harddisk smile




Thanks for sharing your findings, Kong

 By: zephyr49 : January 28th, 2008-03:56
Despite the fact that I work in a highly magnetized and electronic radiation environment (air traffic control center with the huge radar and countless computers and electronic equipment), I still wear my IWC pilot chrono and Oris flight timer. Interestingly, both watches don't deviate much in daily timings as I've kept count before. Maybe the shielding from radiation and magnetism did the trick. The IWC has a anti-magnetic soft iron core while the Oris doesn't but it was my Oris which deviated lesser than my IWC!


Good information, Kong. From now on, i will only be...

 By: Ronald Held : January 28th, 2008-05:45
wearing quartz watches when doing a lot of work on my laptops.

Not sure about quartz.

 By: yw wong : February 4th, 2008-23:02
I had a bad experience with my quartz watch when I was working near some bus-bars in an electrical distribution board.  My watch ran a full one hour fast within a two hour period.  I suess the field is not as strong near a lap-top speaker or hard-disk.

interestinf findings

 By: damien : February 29th, 2008-09:35
thanks kong! guess the old ingenieur would fit the bill.