Over the course of an afternoon, you can gather together all of the components needed to make a simple battery-powered toy car. This kind of toy is about as rewarding to make as it is to run, especially because of the huge number of parts that can be used to make this. You can make the wheels, body, axles and other parts out of many different things depending on what you want the car to look like. Half of the fun with this project is being creative when building the car.
Design a car base by drawing the outline of your car base onto the material you'll be using to make the car. On the underside of the car base, mark where you will attach the axles. Decide which will be the drive axle: this is the axle to which the motor attaches. On many toy cars, it's the rear axle.
Cut out the shape of your car base using the scissors or saw.
Glue or attach the axle holders to the bottom of the car base, along the marks you made earlier.
Glue or attach one wheel to each axis. Leave the glue to dry for a few minutes, then slot the axles into place at the underside of the car. You should leave the car on its side while you continue to build it.
Slide the gear or elastic band onto the drive axle, near the car base. The gear should not rotate on the axle, and you should glue it in place if it does. Make sure the axle still spins freely, but not loosely. This is the axle you will attach the motor to shortly.
Glue or connect the remaining wheels to the axles. Make sure the wheels are fairly close to the body of the car--not too tight, but not too loose. You can trim some excess axle if necessary to ensure it will roll freely.
Loop and twist one wire to the negative (-) terminal on the motor. Repeat for the positive (+) terminal, so that both terminals have leads. If you have an on-off switch, wire this to the positive lead and connect a new wire leading away from it.
Attach the motor to the car base with electric tape. Place it on the edge of the car base, near enough to the drive axle for the gear or elastic band to connect to the motor. If you're using an elastic, make sure the band is taut.
Connect the negative (-) lead of the motor to the corresponding negative terminal or connection on the battery or battery holder.
Tape the battery to the car base. To keep the car balanced, place it over the drive axle on the side of the car base opposite to the motor.
Touch or tape the positive lead to the positive terminal on the battery or battery holder. The motor should start turning, and the car is on its way. To stop the car, disconnect the wire from the lead.
For another afternoon project, try converting the electric car to solar power. Simply replace the battery with a solar cell, and attach it to the car so that it catches the sun at a 45-degree angle.
Look at the voltage of the motor before attaching it to a battery. Make sure you use only batteries that are the same or less than that voltage. For example, if you attach a 2-volt motor to a 9-volt battery, the motor will run extremely quickly for a short time before burning out.