Frank Allan, Science Co-ordinator, Ottawa Board of Education

The world’s simplest speaker can be constructed in a matter of seconds.

Equipment

• soup can (10 cm in diameter, 12 cm high)
• circular ceramic magnet (7 cm in diameter)
• coil of wire (about 50 turns of motor-winding-gauge wire made into a coil with a mean diameter of about 6 cm)
• a “ghetto blaster” with an external speaker jack
• connector wires to attach the coil to the speaker jack

Construction
Simply connect the coil to the speaker jack, place the ceramic magnet on the closed end of the soup can and tuck the coil of wire in underneath it. Disconnect the speakers of the “ghetto blaster” and plug in the coil’s speaker jack to it. Sit back and enjoy the ultimate in sound — well, not quite.

---

Column Editor: Ernie McFarland, Physics Department, University of Guelph, Guelph, Ontario, N1G 2W1

Tags: Electricity, Magnetism