Often called an Euler's Disk (see Youtube), this is a disk that is optimised to spin and roll at the same time. I've checked for some time, and I can see no clear analysis of how to optimise the diameter, thickness and rolling edge. Anyway, the longest video of actual spolling (spin and rolling) is around 2 mins, although one claim is for 4 mins. This idea is to kick off a youtube competition for the longest actual spolling time (it could be spinning as well, if it is easier to time). The disk must be hand spun only, and the material, surface is completely free of choice. However, the weight must be below 500g (about 1lb).
-- Ling, Aug 17 2011

Euler's Disk on YouTube http://www.youtube....watch?v=ug2bKCG4gZY
[AusCan531, Aug 17 2011]

Love it. Have added a link to YouTube. To make it really competitive however you need to have two contestants wired up then have them set their disks spinning at the same time.

The contestant whose disk stops spinning first gets a massive shock of electricity. Just imagine the drama and suspense of watching two Euler's disks winding down and knowing you're going to get zapped if yours stops first. Bun [+]
-- AusCan531, Aug 17 2011


If these could be adapted to include a plywood deck to stand on, I see wicked halfpipe potential.
-- Alterother, Aug 17 2011


When I was a lad, I used to take the rollers from roller bearings, place them on a slick, smooth surface, and press one end firmly with my rather grubby thumb. They would leap up and spoll furiously.

I didn't know it was called that.

Hi, [Ling}.
-- baconbrain, Aug 17 2011



random, halfbakery