How to Build a Good Mouse Trap Car

Remove the bait holder and catch wire from the mouse trap.

Locate the point where the spring at the base of the mouse trap grabs onto the snap (the U-shaped wire that catches the mouse). Cut the U-shaped wire snap as close to the base as possible on the side opposite where the spring grabs onto the snap. Straighten the bends in the snap with the pliers to form a long, spring-loaded lead.

Bend a 90-degree hook into the tip of the lead, 1/2-inch from the end of the lead.

Align the two strips of balsa wood side-by-side. Drill identical 5/32-inch holes centered 1/4-inch in from each end of both boards to accommodate the axles.

Drill a 1/8-inch diameter hole directly in the center of each of the three round plywood wheels.

Cut two 4-inch straight sections of wire from the coat hanger to serve as the car's axles. Slip one of the axles through the hole in one of the wheels and center the wheel on the axle. Attach one of the balsa wood strips onto the axle on each side of the wheel by slipping the axle into the holes in the balsa strips.

Insert the rear axle through the two remaining holes in the rear end of the balsa strips. Attach a wheel to each end of the axle, and glue in place with a bit of epoxy.

Place a single drop of epoxy directly in the center of the rear axle. This drop of epoxy will act as a hook and should be like a blob on one side of the axle rather than an even layer around the circumference of the axle.

Center the base of the mousetrap onto the top of the two rails, with the long wire lead pointing toward the front wheel of the car. Adjust the width of the balsa strips so they are parallel with the two long outer edges of the mouse trap's wooden base. Glue the base of the mouse trap to the balsa strips with some epoxy. Set the car aside to allow the epoxy to dry.

Tie a small loop in one end of a piece of string. Tie the other end of the string onto the hook end of the mouse trap's long lead wire, adjusting the length of the string so the end of the loop is about 1/2-inch shy of the center of the rear axle.

Pull the spring-loaded mouse trap lead backward, toward the rear of the car, and hook the loop of the string over the epoxy hook on the rear axle. Rotate the wheels so the string starts to wind around the rear axle. Keep winding, pulling the spring-loaded lead rearward until the string is tight and the lead is flat against the rear of the car.

Hold the spring-loaded lead securely against the car, and set the car on a flat surface. Release the lead, allowing the lead to pull the string, propelling the rear tires and launching the car forward.