Magnetic Induction Experiment Suggestion

[sammy-e]

Hello,

I am looking for ideas to demonstrate magnetic induction. There are a couple I've found, but I'm having trouble finding something with a little more excitement. The two I've seen are lighting a bulb with a changing magnetic field and launching an object by closing a switch connecting a charged capacitor and a coil. While I like the 2nd, I'd like to find something different because I've seen that one a few too many times. Variations are fine, though.

Any suggestions at all are welcome. Thanks in advance.

 

[Averagesupernova]

Wind about 15 feet of 30 AWG wire onto an iron or steel core (1/4 rod 2 inches long for instance). Connect the two ends ends of the wire that you have wound onto the core to a 1/8 inch phone plug. The type that would plug into a mic jack on a small cassette recorder. Then, plug it into the mic jack on the cassette recorder. Using earphones/headphones put the recorder in record mode and listen through the headphones. MOST recorders allow listening to what is being recorded through the headphone jack. You can sustitute a small audio amplifier for the cassette recorder, but most people already have access to a cassette recorder.
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Now what to do with this. There are all kinds of interesting things to listen to with this device. Start with placing it close to a speaker with audio playing through it. You can attach it it various objects that may vibrate and hold a magnet close to it. Your imagination is the limit.

 

[sammy-e]

Sounds pretty cool and I like the simplicity, but I'm sort of looking for something with movement or a more visible effect. Definitely on the list, though...

 

[Bob S]

Wind about 15 feet of 30 AWG wire onto an iron or steel core (1/4 rod 2 inches long for instance).

The eddy currents in the iron will significantly attenuate the audible frequencies. I would use a ferrite rod if I knew where to get one.

 

[Averagesupernova]

The eddy currents in the iron will significantly attenuate the audible frequencies. I would use a ferrite rod if I knew where to get one.

It always worked for me. In fact, a single turn of one of the wires feeding a conventional telephone set wrapped around this gave nice audio.