How to Make an Easy Mouse Trap Car

A mousetrap provides the propulsion for a toy car.

Building a mousetrap car can help children learn about propulsion and other physics topics. The car uses a mousetrap as a source of energy for propulsion. You attach the spring of the mousetrap to a cord or a length of elastic. You wind the cord around the axle of your car's back wheels. When the trap is sprung, the cord is whipped off the axle, causing it to spin around. This drives the car forward. A mousetrap car can be a great project to share with kids; the project can be completed in an afternoon.

Things You'll Need

• Mousetrap
• Drill
• Saw
• Ruler
• Scissors
• String or cord
• Screws
• Lightweight wood such as balsa wood
• Four eye hooks
• Dowel rods
• Toy wheels

Instructions

1. Measure the depth of the toy wheels and the width of the mousetrap. Saw two lengths of dowleing long enough to accomodate the width of the mousetrap plus twice the depth of the wheels, plus an extra half-inch.

2. Drill four small pilot holes into the ends of the mousetrap. Screw in the eye hooks. Slip the dowel axels through the holes. Fit the toy wheels to the ends of the axles.

3. Measure off and cut nine inches of string or cord. (You may need to adjust the length of this later.) Tie one end of this to the rear axle of the mousetrap car. Tie the other end of the string to the arm bar of the mousetrap.

4. Wind the string onto the rear axle of the car. You do this by turning the back wheels in the opposite direction to the way you want them to spin when the car is in motion. Keep winding the string, pulling down the arm bar and setting the mousetrap. You must wind all of the string tight, with no slack.

5. Set the car down on an uncarpeted floor. Using your ruler, set off the trap. Your car should now move across the floor.

Tips & Warnings

• Construction toy sets can often provide you with useful materials for your mousetrap car.

• Experiment with different wheel sizes. Larger wheels can often let your car travel further. Wheels can be made from foam board, discarded CDs and even vinyl records.

• Mousetraps can be very dangerous. Make sure that the trap is not set before you start working. Keep your fingers away from the mechanism once the trap is set.

• Keep your mousetrap car away from younger children and pets.

References

• Lynne Clos: Mousetrap Car
• Wired Magazine: Geek Dad: Sunday Afternoon Project: Building a Mouse Trap Car
• Mousetrap Car and Vehicle Propulsion Theory: Mousetrap Car Construction Tips and Ideas

Resources

• Doc Fizzix: Mousetrap Car and Vehicle Kits