Courses: P4, P14, P16, P41
The copper tube we're using is actually a piece of wire salvaged from the BLAST project at MIT. They would bend this material into loops to wind a huge magnet with a 1 Tesla field. The hole through the middle was used to pump cooling water. This is special copper that has a lower resistivity than typical copper plumbing, and hence it generates higher eddy currents.
First drop a steel nut through the tube to show how quickly a non-magnet falls, then drop a neodymium magnet through. Place a metal pie plate under the tube to catch the nut and the magnet, partly to keep them contained, but mostly to make a louder sound when the object hits the floor.
A camera mounted above the tube and looking down through it is great for watching the magnet slowly fall. The small Sanyo cameras work well for this, but almost any camera with some zoom ability would work. Focus about 1/3 of the way down through the tube. The silver pie plate at the bottom will provide enough reflected light to make the magnet nicely visible in the tube.
Tags: Faraday Tube