How to Build a Simple Mouse Trap Car

A basic mouse trap is the engine for a mouse trap car.

Building a mouse trap car is a common high school physics class project because it demonstrates the properties of potential energy, energy transformation and inertia. A key element in any mouse trap car project is the design phase. Your mouse trap car can be optimized for either speed or distance, and you or your student should expect to spend some time experimenting with different design elements to come up with creative ways to use the materials at hand to produce your ideal mouse trap car.

Things You'll Need

• 4 eye hooks
• 2 light cylindrical rods
• 4 rubber washers
• 4 wheels
• Epoxy or super glue
• Wooden mouse trap
• Stiff wire (optional)
• String

Instructions

Design Your Mouse Trap Car

1. Decide whether you want to design your car for speed, distance or a balance of both elements. To optimize your mouse trap car for distance, consider adding a lever arm, reducing friction and increasing the axle to wheel ratio. To optimize for speed, decrease the weight of the car by using lighter weight materials, minimize rotational inertia on the wheels and decrease the axle to wheel ratio.

2. Look for materials you could use for the body of your car. Be creative in your hunt for materials and do not be afraid to experiment with unlikely items.

3. Look for materials for the wheels and axles of your car. Keep your design considerations in mind when choosing these items.

Attach the Wheels

1. Attach two eye hooks to each of the short ends of your car body. They should jut out from the front and back of the car to hold your axles in place. Experiment with the placement of the eye hooks -- place them closer together or further apart, or try putting them below the car instead of on the sides. Make sure they are parallel to each other.

2. Insert the axles through the eye hooks. The axles should be parallel to each other and longer than the car to minimize friction.

3. Slide the rubber washers onto the four ends of the axles. Position them close to the eye hooks to keep the axles in place. Leave some space between the rubber washers and the eye hooks to avoid friction.

4. Place the wheels on the axles. Glue them in place.

Attach the Mouse Trap

1. Place the mouse trap on the top rear of the car body. Glue it in place.

2. If your design calls for a lever arm, attach a length of stiff wire to the jaw of the mouse trap. Tie one end of the string to the lever arm or directly to the jaw of the mouse trap if your design does not call for a lever arm. Place a drop or two of glue on the knot to secure it.

3. Coil the loose end of the string around the rear axle of your car. Coil the string opposite to the direction you want the car to move.

4. Test your car. Make adjustments to the lever arm, wheels, axle and body until you have optimized your car for speed, distance or both.

Tips & Warnings

• Plan to experiment and revise your design as you build and test your car.

• Use caution when setting off the mouse trap to propel your car. Be sure your fingers are well out of the way.

• Always use epoxy or super glue in a well-ventilated area.

References

• Doc Fizzix: Making a Long Distance Traveler
• Doc Fizzix: Making a Fast Speed-Trap Racer
• Mouse Trap Car