Probably the coolest source of educational science demonstrations I've encountered is this very book-like website written and run by Simon Field. Field has 30 nifty toys and gadgets that can be made quickly, cheaply and will amaze adults as well as kids. This is the only place I've seen that tells you how to make a magnetic linear accelerator, also known as a Gauss Rifle - it uses magnetism to shoot tiny steel balls. The secret to Field's method is that his demos are very small, requiring small amounts of material, energy, or money. Most of his experiments can be assembled - even if you buy the stuff - for a few dollars, and can fit in your palm. His instructions and visuals are simply the best I've seen in any how-to-book. Most wonderful of all, it's entirely up on the web for free. Hats off to you, Mr. Field. (He does sell kits, and parts, which may help pay for his server, I guess.)

-- KK

Science Toys You Can Make With Your Kids