1. The problem statement, all variables and given/known data I want to run a magnetic liquid past a coil to product a current. In a vertical tube I want to inject an air bubble to push the liquid upwards. Of.course the air escapes the top and the liquid re-cycles. - Like a variant of Faraday's Generator with moving liquid magnet rather than fixed. What liquid can I use? 2. Relevant equations 3. The attempt at a solution I saw one running on the youtube some years back ( before July 2011) but can no longer locate it.