I am trying to make a DIY stir plate but all the "pea" does is jump around. It won't spin. I am using a 12v dc 4 inch computer fan powered by either a 5.9 v or a 9 v wall wort. I have tried 1 magnet, 2 magnets one on top of the other, and 2 magnets on opposite sides of the top of the fan. I have...