Ben Light displayed Kinetic Sculpture 5 at the ITP Winter Show last month. When the user waves his/her hand over a photoresistor, a push solenoid is triggered, causing a rod to decouple and swing to the other side. Whatever losses are sustained due to conservation of energy are then recovered by a strong magnet that gives the rod that extra pull it needs to couple to an identical solenoid on the opposite end.
A row of five rods lets the user play with sequencing the movement, which alludes to classic demonstrations of harmonic motion. A maker with a nuttier sensibility would think this project is on track to be a perpetual motion machine, but I think Ben knows better.
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Um, there aren’t any “losses … due to conservation of energy”. As the word “conservation” might suggest, no energy is lost or gained in this system, or indeed ever. Nor is anything “recovered” by the magnet.
Some minuscule amount of energy is converted to heat in the bearings the rods turn on, probably more (but still a tiny amount) by air resistance. I’d guess the biggest expenditure of energy is transferred kinetically by the rod whacking into the magnet. So where does that energy come from? Could it be the big solenoids plugged into the wall, kicking the rod around when you hit the switch?
Is “nuttier sensibility” a euphemism for something? This is a cool project. Why stretch to associate it with fraud it doesn’t seem to be claiming, and which can be dismissed with 20 seconds of thought?
Um, nobody’s associating anything with fraud. “nuttier sensibility” just means ‘slightly insane’, as in someone might see this thing, be impressed with it without knowing how it works, and ‘get inspired’ to spend the next 20 years of their life trying to build a perpetual motion machine on the ‘hanging, swinging weights and magnets’ principle…
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