Hand Generators - steel wool

[Jeff Briggs]

The glowing steel wool was a big favorite of my class, but make sure you limit the number of steel wool strands to protect your generators.  Using 3-4 strands was no problem but we had one group that had probably twice that in their experiement and in an attempt to get that many strands to glow, ended up breaking a couple of teeth off the gears in the generator.  Don't let the students crank the generators too hard or the plastic gears can become stripped.  The best way to prevent that is to warn the students of over-cranking and by limiting the number of strands of steel wool.

[Matt Anthes-Washburn]

Also, keep an eye on the bundle of steel wool. You don't want students trying to run current through it and setting the whole bundle on fire.