I am reffering to a method used by some lotto operators to determine the winning numbers. In the particular method a number of balls having the same size and (supposedly) weight are put inside a canister where the are put into random motion by means of pressurised air. At some point, the influx of pressurised air stops and slowly the balls come to rest - at which point a ball finds its way out from a hole at the bottom of the canister. Thus, and by reffering to the number painted on the ball, the winning numbers are determined in succession. However, I remember from my highschool elementary physics course a similar experiment - which our physics professor code named "Maxwell's Devil" - where a number of balls where put into random motion inside a spinning sphere and at the end the same one ball always came out of the hole in the canister. It turned out that this particular ball was slightly heavier than the rest, thus forcing it self as the first ball always to come out. I am trying to locate on the web a practical and theoretical explation of the physics involved, but unfortunately I cannot find anything related to this matter. Can any one help with any references? Thanks.