This machine manipulates small spherical rare earth magnets, slicing one at a time from the end of a long chain, moving it around a bit, then dropping it back to re-connect at the tail end of the chain.
It also demonstrates a little snippet of science called eddy currents. Watch how slowly the magnet falls through the aluminum tube compared to falling through air: the falling magnet generates an electrical current in the tube, and that current in turn generates a magnetic field that opposes the movement of the magnet, slowing it down dramatically. [more in description]
“History in Audio Recording: The only working pallophone in the world(2010), plays back the earliest radio station recordings ever made. It used light bouncing off a tiny mirror to expose a strip of film. A photoelectric cell is used to read the recordings. The film recorded waveforms of sound as tiny black stripes. Demonstration on…” more
graffiti supply vending machine
Complete instructions for building this device