I'm looking for a super simple project for an Engineers week class visit for the 5th graders. We made bristle bots last year. Looking for a cool similar project that can be made for under $1. Right now I'm considering the joule thief. Suggestions?

I'd suggest the Edge-lit cards. Under $1, good opportunity for teaching the kids about total internal reflection and thereby, how fiber optics work. Each kid needs an LED, battery, pushpin and a small sheet of PETG plastic.

http://www.evilmadscientist.com/article.php/edgelit2

Thanks,

Its perfect. The class will go wild. I plan on telling the kids some of the advancements of electronics, and this is a perfect application for the LED.