Remagnetising Magnets

[slatts]

This seems like a really dumb question but does anyone know how to remagnetise magnets? I always thought they stayed magnetised but they don't. Thanks

[Ocker]

If you have a nice really heavy coil place magnet in coil and tap on & off a few times on a car battery
It's on the off cycle the magnetising happens, with the back EMF doing the work
Magneto Motive Force = Ampere x Turns

[lada]

Our department spent some money and we bought magnetizer from PASCO scientific. It is a bit time consuming but I have remagnetisied all our bar magnets.
Lada