Rolling Magnet on a Copper Plate

PIRA 5K20.18

Make a ramp with the 3/4" thick copper plate shown at right, a wood box clamped to a table top with c-clamps, and duct tape to keep the bottom of the ramp from slipping.  A 30 to 40 degree angle seems to work the best.  Roll one of the cylindrical ceramic magnets down the ramp.  It will roll very slowly due to interactions with the induced eddy currents.

Roll the magnet at an angle towards one of the sides and it will curve back towards the center of the plate.  Challange your students to explain this.

You can also have students hold the magnet in their fist while moving it back and forth over the copper to feel the interaction with the induced eddy currents.