On Fri, Sep 18, 2015 at 12:42 PM, Charles Craft wrote: > http://www.teachersupplysource.com/category/52478/electricity/?sort=3Dpri= ce > > That's certainly a better price for bulbs, but if they work as I hope, Christmas tree bulbs may be a better option - and bonus wire and sockets. :-) I have a fairly "stupid-simple" battery holder in mind. (PVC water pipe, two screws and a couple rubber bands). It definitely allows the kids to put the batteries in backwards. I'm thinking that's going to be the basis of the conversation about polarity. Once they get that, I think we can step up to an LED that already has a resistor. (no soldering yet) I'm also hoping the light bulbs get a bit warm- certainly not enough to burn someone, but a solid lesson in "electricity =3D heat" Move on to a little piezo beeper. Maybe a little motor. That might lead to bristle bots. Add switches to the mix. There was a post a couple years ago here about a simple pressure pad switch that might be interesting to add (paper, tin foil, and felt in a zip bag) At some point we mix in the idea of a schematic. I'm guessing that's probably enough for a few weeks at this age level. I'm thinking about letting them take the first parts home and do some "testing" explore the idea of conductive vs non-conductive. I don't really see anybody getting hurt if we can keep them from sticking it a mains socket. Probably need to start them out with a "look, don't touch" demo of something really destructive so they have a visceral understanding that there can be danger here. Might be time to break out the Jacobs ladder... Opinions invited -Denny --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .