VISIBLE, SLOW FALL
Get a length of copper plumbing pipe and drop a small neodymium magnet into it. The magnet will fall slowly. If you choose the magnet and the pipe to give a slip-fit on the magnet, the rate of fall will be very low. If you glue several NIB cylinder magnets end-to-end with repelling faces superglued together (a trick in itself!), the rate of fall will be even slower. And last: purchase some sheets of that green "magnet viewing film" from Edmund Scientific or other edu. supplier, cut them into strips and tape them around your copper tube, and the audience will be able to "see" the falling magnet as the field pattern moves along the seets of micro-encapsulated film. Or a messier version: wet the copper tube with gooey black ferrofluid, and watch the pattern as the magnet slowly falls.
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