There's a similar demo at the Exploratorium in San Francisco - you can drop disks of different materials (and with different cutouts) through the electromagnet

There's a similar demo at the Exploratorium in San Francisco - you can drop disks of different materials (and with different cutouts) through the electromagnet and see the different rates at which they drop. I recall it also had a thoughtful warning sign instructing folks to keep their (magnetic stripe) BART cards away from the electromagnet!