How to Make a Mouse Trap Car Out of K'Nex

Press two stoppers (small, gray, hollow barrels) onto a 4-inch K'nex post about 1 inch from each end. Thread the middle, loose hole (circular shaped) of a corner connector onto each end, and press a stopper onto each end of the 4-inch post to hold each corner connector in place. Thread the middle star hole of a large wheel onto each end of the 4-inch post, and secure them into place by pressing a stopper onto each end of the 4-inch post. This will create a pattern of stopper-wheel-stopper-corner connector-stopper from each end of the 4-inch post. Each wheel should turn with the post, but each corner connector should spin freely.

Press an eight- or 10-inch post onto each corner connector and press each of the other ends onto two separate half-circle connectors. Join the two ends by threading a 3-inch post through the star hole of each half-circle connector, arranging the connectors 1 inch from each end. This is the front axle, and the other end with the large wheels is the rear axle.

Slide a small, loose-spinning wheel onto each end of the front axle and secure each into place with a stopper.

Mount a mousetrap in its closed position onto the frame of the car with the rubber bands. Face the trigger-end of the mouse trap toward the front of the car. Apply the rubber bands by stretching them over the front of the vehicle and wrapping them around the middle of the car's frame, as well as the mouse trap.

Use the scissors to cut about 24 inches of kite string. Tie one end to the spring-bar of the mousetrap.

Set the mousetrap by bending back the spring-bar, flipping the trigger-rod over the top of the bar and applying the trigger to the trigger-rod. Carefully wind the other end of the kite string around the rear axle.