Assemble these materials:

• 6 cm (2.5 inches) of thin copper wire *
• a small piece of sandpaper (to take the insulation off of the ends of the wire) *
• two battery holders and batteries *
• a wire with alligator clip ends *
• tape

Cut or break a 6 cm piece of the thin wire. Although it looks like copper metal, there actually is a coat of transparent paint on the wire. Scrape off the paint from the last 1/2 cm of each end, using the little piece of sandpaper or a knife. Orient two battery holders (with batteries already in them) plus-to-minus, but then separate them 5 cm apart. Put the little wire through the two holes in the ends of the battery holder to make a "swinging bridge" between them. You will have to bend the wire a little bit so that it fits (if it isn't bent already!).

• Connect a wire to the free end of a battery holder, and again touch the other end of the wire to the remaining free end of the other battery holder, so that we are driving a current through the wire bridge. Nothing interesting will happen (but we have to check!).
• Now place a cylindrical magnet under the wire bridge, and start and stop the current.
• Turn the magnet over, and see what effect this has.
• Hold the magnet at other positions near the wire, and see when the wire responds to the magnet and current.