Science projects can introduce kids to the practicalities and theory of real life applications. You can teach kids about working with electrical circuits by designing a homemade windmill driven by a small electrical motor and run from a battery. You should design the circuit in series, with wires running connecting the various circuit components from positive to negative.
Cross two craft sticks and secure them together with glue. Using the end of the scissors,make a small hole in the center of one of the craft sticks. Fit the shaft from the motor into this hole. Tape the motor to the edge of a wooden block with the craft stick cross hanging over the edge. The cross should be able to turn, unimpeded.
Connect a wire to the positive terminal of the battery. Connect the other end of the wire to one end of a switch.
Connect a wire to the other terminal of the switch. Run the wire to the motor. Attach the wire to one of the motor terminals.
Attach another wire to the other motor terminal. Run this wire back to and attach it to the negative terminal of the battery.
Turn the switch on to start the motor running the windmill.