How does it work?
The Euler's Disk, invented by Joseph Bendik is an educational toy that has been the subject of a number of scientific papers.
This video uses a contact microphone to magnify its mesmerizing sounds 🔊
https://video.nostr.build/5b813162e6b81b63f1ba5214f4ed18844cf1d8268877d5c5ea9da04c0029a5b0.mp4
Discussion
is it a magnet? i think it's a magnet, this is probably from eddy currents, they are very low loss
i have a big-ass "fishing magnet" and i've got a brush cutter attached to it (steel) and when i bump it, and it starts to oscillate, it takes almost a minute to stop vibrating
the magnetic field effect limits friction somehow, causing the system to continue to oscillate a lot longer than you expect
https://en.wikipedia.org/wiki/Euler%27s_Disk
yeah, the miror is slightly concave so the disk dwells into it, and other than that, polished so the friction is low and its decay is slowed
It makes me want to try building a version that returns the dissipated energy, thereby maintaining the effect for as long as the device can keep pushing.
according to the article the thing that will lengthen the effect the most is reducing friction, so probably if you made the disk and the surface coating with extremely smooth nylon or teflon it would probably prolong its decay by another 10-20% compared to steel or steel and glass... i don't know what things can be done to reduce friction generally, i just know nylon and PTFE have very low friction coefficients, lower than polished steel for sure
probably it's possible also to use a tuned oscillating magnetic field, maybe an array of coils underneath, and make the disk magnetised, and you could have it seem to spin forever, but of course when the power cuts out it will decay
a device that could keep one of these spinning in one of its phases constantly is just a matter of tuning, probably needs a little work but essentially what it would do is you'd tilt the table ever so slightly in one direction, and spin that tilt at a given speed and the result would be the disc would not stop being in the state the speed is tuned to, and it could be under 1mm of tilt required, making it imperceptible until you get up really close to see the mirror shifting the surroundings