To demonstrate Lenz�s Law by using a magnet to stop a spinning aluminum disc.
Location
Room 146; shelf N1; magnet on M6.
Description
Attach the aluminum disc to the rod using the rod clamp and have it face the students as shown above. First show that the aluminum disc is non-magnetic by having a student verify that there is no attraction to the magnet. Then give the disc a good spin and see how long it takes to come to rest without any interruptions (top right image). Then give the disc another good spin and hold the magnet with the disc in between the two ends (bottom left image shows the disk slowing down, bottom right image shows the disk at stop). The class will see that the disc decelerates much faster due to eddy currents being induced within the disc creating a magnetic field opposing the motion.
