EMF stands for an "electromagnetic field" and refers to a field of radiating waves of invisible energy. This energy is often useful--when produced in the form of radio waves, microwaves or even X-rays. However, its effects can also be dangerous or unwanted. Many people are concerned that common sources of EMF radiation--like cell phones or Wi-Fi routers--could have a serious impact on health. They often support this claim by demonstrating how invisible and seemingly "harmless" electromagnetic fields have the power to disrupt wristwatches and other electronic and mechanical devices.
How Does EMF Affect Analogue Watches?
Analogue watches are the most common form of wristwatch--with a "big hand" and "little hand" and generally powered by being wound up, or by batteries. Because a majority of these watches are made from metal, even mild magnetic fields, like those generated by a set of speakers, or a homeopathic magnetic bracelet, can effect the operation of a wristwatch. At one spectrum, the magnetism might disrupt the rhythm of a watch so it runs slow or fast. A more extreme situation might see a metal component of the watch become magnetized--stopping the clockwork process entirely.
How Does EMF Affect Digital Watches?
Because digital watches are entirely electronic, and have no moving parts, exposure to strong magnets should not affect their functioning. However, the electronic components could be vulnerable to a powerful electromagnetic pulse--a burst of electromagnetic radiation or fluctuating magnetic field--which could permanently burn them out.
What Sort of EMF Could Affect Watches?
The average person generally won't be exposed to electromagnetic fields powerful enough to disrupt the function of a wristwatch--those that do might include people wearing homeopathic magnetic bracelets. EMFs only become a problem for people working with powerful electromagnetic equipment, such as MRI scanners. They will often have to remove their wristwatches before going to work, as otherwise they can lose time or have their watch cease functioning altogether.
Is There a Watch Resistant to EMF?
Since the 19th century, watchmakers had been experimenting with "anti-magnetic watches." The first anti-magnetic pocket watch was produced by Vacheron Constantin in 1915, with watchmaker Tissot assembling a non-magnetic wristwatch 14 years later. Today, there are many brands of analogue watch made from non-magnetic materials like hydrocarbons and nickel alloys. These watches will continue to keep accurate time even after being exposed to very powerful electromagnetic fields, including those of MRI machines.