ShelfordPrefect t1_j5qzs5e wrote

Another factor in favour of the big pool: at the same rotational rate, the big pool will have less shear because the difference in speed between two points a given distance apart is smaller than the same two points in the small cup, so I would imagine less energy would be lost to turbulence


ShelfordPrefect t1_iszecgb wrote

If you have a suitable low voltage power supply, the best price/performance ratio might come from a cheap cordless drill. I saw an instructable years ago where someone was using a drill turning a roller rubbing on a bike wheel for a slow reciprocating effect.