I’ve got a couple of magnets that my son and I want to use for his science fair project. I don’t know their composition, but they’re about 100mm by 175mm by 20mm thick, the poles are on the faces, and they’re held in a cage so that the poles are aligned N-S-N-S. They’re out of a SEM and had to be used for beam bending, but they’re a lot bigger that any Wien filter I’ve seen. They can affect a monitor’s display from several feet away (it has taken twelve hours for my TV to nearly recover.) On the other hand, I was able to buy something by credit card shortly after carrying them near my wallet.
I’m starting to wonder how safe it would be to place these things in the middle of a school auditorium. Does anyone have enough experience with magnet safety to give a give a very rough estimate of their safety or to give some basic suggestions on safety tips. I am already planning to put up a warning for people with pacemakers; I assume that shielding is beyond my capabilities.
Also, I started to get a headache after playing with these things for an hour. It would take a hypochondriac to link the two events, right?