One look at any of these gadgets you can make, and your friends will call you a mechanical genius—or a mad scientist! Build a rocket-propelled toy car or a secret place to hide your treasures from snooping little kids. Grow a pumpkin so big, even an adult can’t lift it. Make an automatic dog feeder, a mechanical snowball thrower, or some storm-predicting bells. All fifteen “Amazing Stuff” projects produce toys that are more than playthings. Yet all you need are some pieces of wood, nails, oatmeal boxes, jar lids, and Popsicle sticks. And you just use a hammer, screwdriver, and other tools from around the house—plus a couple of cheap electric motors you can buy at any electronics store.