Fun stuff. The nonmagnetic but conductive materials will see a changing magnetic field, or will “break” field lines, as the jargon goes, which induces eddy currents to flow and produce a field (that’s Faraday’s Law), with the induced field opposing the change (Lenz’s Law). This gives a braking effect, as you can see. Interesting that the nickel is largely unaffected by this; the composition is 75% copper and 25% nickel, while for the quarter, it is 91.67% and 8.33%.

I’ve linked to eddy current effects before, but still wanted to do my own video. I tried to narrate it while filming, but keeping everything in the frame and talking (while my hands were occupied with the demo) was too tough. I did a couple of disastrous takes and then had a fit and stormed off to my trailer, vowing to never work with myself again. I finally calmed myself down and did the silent shot, then waited impatiently for me to do the post-production.