I’ve had an Apple Watch with a watchband that holds together by using magnets the length of the band. Over the last couple of months, the “strength” of the band, IOW, the tightness which holds the 2 bands together has steadily decreased. It got to the point where slightly bumping my wrist would cause my watch to come off. There was no visible damage to the band. I really like the band when it works properly so I ordered another one. The new one works just like it should. It holds tightly.
How is this possible? I’ve never heard of magnets losing their effectiveness.
I was so predisposed to the idea that magnets are forever (or at least close enough to it for human purposes) that it didn’t even occur to me to google it. I guess the daily “snapping” the bands together cause the magnets to weaken.
Ok. The diagram just says it “will feel weak”, but I guess it’s worse than that.
Impact can make a magnet loses effectiveness, but the amount from a watch band clanging shut, especially one with a cushion, seems very unlikely to me.
Maybe the magnets are moving around inside. I don’t know how they’re contained within the strap, but conceivably they could rotate or shift in some other way over time, perhaps exacerbated by the flexing of the strap.
I remember as a kid you could buy little packs of several different magnets in the toy aisle. The horseshoe always had a little block of metal attached, but I didn’t know why until way into adulthood:
I have seen somewhere that those watchbands use flexible magnets, IOW refrigerator magnets. They are not very strong since they are a mixture of plastic and magnetic material that is not very dense and subject to demagnetization. Strong magnets may re-orient the magnetic material so it is effectively demagnetized. The material may also be low quality that loses its magnetic orientation simply from vibration and impact.
A lot of metals can magnetize or demagnetize. The heads of a cassette tape player could magnetize, and that was one cause of players “eating” tapes. At least, that’s what the guy at Radio Shack told me. I had a player that I took to Radio Shack once to ask why it had started eating tapes, and the manager ran what he called a “demagnetizer” over it while it was on PLAY (without a tape). Worked fine after that.
Not only that, but I discovered that a cassette player can trigger the stolen book alarm at a library. Also, if you run a cassette player through the thing that keeps books from triggering the alarm, it can erase them.
Since the books have a metal strip in the spine, I assume there’s some process of magnetizing and demagnetizing going on when they are returned and checked out.
