This week I began Magnetism in class and wanted to "wow" my students with Magnetism. Take a Neodymium magnet to show the concepts of Ferromagnetism and Diamagnetism. I used an American "crisp" $5 bill and taped a thread to it. Hanging it from a crossbar and using the Neodymium magnet, you can attract the bill. Then... I took a WHOLE flake of "Total" cereal and taped it to a thread, hanging it from the crossbar. The Neodymium attracts the flake to about 30 degrees from the vertical! If you REALLY want to astound your students, take two FRESH grapes and stick them on each end of a tiny dowel rod (like a "grape barbell") and hang the arrangement from the crossbar. I held the Neodymium near one of the grapes and the grape rotated AWAY from the magnet. When the students see that food is repelled from a magnet, they are amazed! The Diamagnetism of water is demonstrated in a cool way!
Very educational indeed. To maximize the effect, you should consider using neodymium grade 52 which is the strongest up to now. Careful with it though.
Posted on April 15, 2012 at 8:29 am