To help his physics students understand the concept of electromagnetic (EM) induction, Brian Lamore, physics teacher at The Chinquapin School in Highlands, TX, devised an experiment involving strong neodymium (Nd) magnets, #28 magnet wire, and the Vernier Instrumentation Amplifier.
To connect the concept with a relevant application, Brian used older hard drives and floppy disks as examples, since they operate on the principle of EM induction—where a change in magnetic flux induces an emf in a conductor. When the reading head with its small coil moves over the magnetic surface of the disk, small signals are interpreted by the coil as digital 1's and 0's.
In class, Brian wound the wire 50 times around his index finger, sanded the wire's ends, and inserted them into the Amplifier. He showed students the results when one magnet passed the coil, when five of all the same polarity passed, and when three of one polarity and two of the other passed. Each polarity reads differently, thus signaling digital 1's and 0's.
Brian even set the coil in harmonic motion and ran a magnet past it to produce a damped sinusoidal waveform. “This relatively simple experiment has great potential for investigations into not only electromagnetism, but also electronics and calculus,” Brian said. Brian used Logger Pro to collect and graph all data.