This is a throwback to 5th grade… my first science fair project, setting the tone for the next six years during which these were the only academic things that mattered.
This AC induction magnet was not my design, but the fabrication and tinkering was hugely educational… I disassembled a transformer to harvest the laminations, then wound concentric coils of enameled wire and fed them with AC that was 90° out of phase via a huge 80µF non-polar capacitor bank. The result was a crazy magnet that would induce eddy currents in low-resistance metals and then powerfully attract their fields with a 60 Hz hum… picking up copper, aluminum, silver, and gold.
Science fairs became my raison d’être all the way through school, letting me focus on projects rather than crank-turning and memorization. And, looking back at all my gizmological bikes and nautical geekery over the past decades, it appears I never outgrew this. (As I gaze at this pic I can STILL remember the warm buzzing of the metal plates, they way they would clank onto the lams, and the shocked expressions of the judges.)
This was me in the fifth grade at Louisville Country Day School. I skipped the sixth, then the following year started exploring relay logic and switching systems.
NOTE: Someone has archived the original article: The Master Magnet