An ammeter is made by hanging a magnet from a string inside a tube around which is wrapped a coil of wire carrying an unknown current. Assembly Cut a 2 cm length from the tube. Wind a coil of at least 100 turns of magnet wire around the section of tube. Leave at least 10 cm of wire free at each end of the coil. Use masking tape or hot melt glue to hold the coil in place on its tube.
Hot melt glue the tube to the wood base.
Sandpaper the ends of the magnetic wire to remove the insulating layer of enamel. The ends of the wire should appear as shiny copper. Take one free end of the wire from the coil. Fold the aluminum foil into two rectangles, several layers thick and about 1 cm x 2.5 cm. Slip the bare copper end of the wire into the aluminum foil and fold the foil over several times.