This Studio project combined mechanics with electromagnetism. The e.m.f. induced in a set of vertically displaced coils as a magnet was thrown inside a cylindrical column was measured. The data was imported into a computer and speeds of the falling magnets were determined using two approaches. One was a naive approach determining speed from distance divide by transit time. The distance was the length of the coil. In a more accurate approach, however, we theoretically investigated the magnetic field due to a moving dipole inside a pickup coil. From this a mathematical model was derived which was fit onto experimentally determined curves, yielding accurate estimates of the velocities.
An interesting demonstration of eddy current Plastic pipeis made by dropping a spherical or a cylindrical magnet down a copper pipe. The magnet does not fall as quickly as it falls due to gravity alone, showing the eddy currents induced in the copper pipe oppose the change in magnetic filed by creating opposing magnetic fields which slows the fall of the magnet.