Geared-Up Gadgets

Build five fun gadgets and learn about gears and transmissions.

• Create a helicopter model with a rotor that spins using a rubber band-powered motor.
• Assemble a spinner toy that you wind up to launch a fast-spinning top.
• Make a centripetal force machine that flings its arms outward at high speeds.
• Build a hand-mixer that demonstrates a gear train.
• Construct a cool aircraft launcher that flings a model vehicle across the room on a zipline.

A 24-page manual guides your model building and experiments with step-by-step illustrated instructions.