Simple homemade electric motor, made from scrap. Great to show children how electric motors work and as an introduction to simple physics.
Whilst there's plenty of basic/children's science books that have experiments to build motors, I've always found that they are difficult to actually get working. This design is a bit more complicated but works really well.
I'll follow up with a how to guide.
Or if you don't want to make your own please check out some of our science kits, e.g. http://www.scientist-online.com/technology-electronics/electric-generator