As I was bored at the lesson, I did some thinking of my own and magnets always fascinated me, still kinda like black magic. Anyway, i was thinking abou creating this: http://img201.imageshack.us/img201/7476/prepetummobile.jpg [Broken] I created this in paint as fast as possible so it's not super clear, but the light blue lines in the vacuum tube hae to represent the direction in which the magnets point their energy or whatever they deliver, the magnetic ball is, at the surface, of the same type as the other magnets, so instead pulling together they should be pushing each other, from each other, right? Place the tube horizontal on a surface, create vacuum in the tube to reduce friction, put the ball in it and give it a little move... prepetum mobile? My teachers said it Could be possible but you have to research much more than I did yet.. In short: can the ball move without stopping if the magnets are pointing in the right direction?