Kreider Physics Page

 Mouse Trap Car


What is a Mouse Trap powered car and how does it work?

A mouse trap-powered racer is a vehicle that is powered by the energy of a wound-up mousetrap's spring. The car works when one end of a string is tied to the arm on the mousetrap and the other end is wound around an axle. By winding the string around the axle the mousetrap's spring is stretched providing stored energy. As the mousetrap is released it pulls the string off of the axle causing the wheels to turn and making the car move

How do you build a mouse trap powered racer?

There are many ways to build a mousetrap powered vehicle. The best way  is to apply your knowledge of the laws of physics, finding a balance between all the parts and any variables that affect the mouse trap vehicles performance. 

What are the  instructions for making a mousetrap vehicle?

There are many good designs that will work, you need to test your vehicle and make changes to improve the performance of your mouse trap vehicle.  Check out "The Plan!!" for several websites on Mouse Trap Car plans.


How it Works

Friction and Design

(From Dr. Fizzix)

Mousetrap car and vehicle propulsion


 F(Force)=M(mass) x A(acceleration)

 V(velocity) x T(time)=D(distance).

 The PLAN !!

Plan #1

Plan #2

Plan #3

Photo Gallery

Owner's Manuel

Project Design Tips 


 The RULES !!

Mouse Trap Car Distance Contest

Build a vehicle powered solely by the energy of one standard-sized mouse trap, (1 3/4" X 3 7/8"), that will travel the greatest linear distance.


1. The device must be powered by a single Victor brand mouse trap (1 3/4" X 3 7/8") Other brands may be used if permitted.

2. The mousetrap can not be physically altered except for the following: 4 holes can be drilled only to mount the mousetrap to the frame and a mousetrap's spring can be removed only to adjust the length of the its lever arm.

3.  The minimum number of wheels on the vehicle is 3;  any more is acceptable.

4. The device cannot have any additional potential or kinetic energy at the start other than what can be stored in the mousetrap's spring itself. (This also means that you cannot push start your vehicle.)

5. The spring from the mousetrap cannot be altered or heat treated.

6. The spring cannot be wound more than its normal travel distance or 180 degrees.

7. Vehicles must be self-starting. Vehicles may not receive a push in the forward direction or side direction.

8. The vehicle must steer itself. Measurements of distance will not measure the total distance traveled only the displacement distance.

9. Distance will be measured from the front of the tape at the starting line to the point of the vehicle that was closest to the start line at the time of release.

10. The instructor has the final decision as to the appropriateness of any additional items that might be used in the construction of the racer.

11.Each contestant will be given TWO attempts. The winner will be that racer which has obtained the greatest distance on any one of the two attempts. Any ties will be decided by a single run off between the racers that tied.


 The GRADE !!

The following assessment criteria will be used to evaluate your project.


10 points:  Neat construction and assembly. Excellent attention to detail.

8 points: Good construction and assembly and good attention to detail.

6 points: Car holds together, but looks like a last-minute project.

0 points: Poor construction and assembly. No attention to detail.



10 points: Unique theme and original design. Excellent level of creativity.

8 points: Interesting theme. Good level of creativity.

6 points: Basic theme. Basic level of creativity.

0 points: No detectable theme. No apparent creativity.



10 points: Travels 5 meters in a straight line. Final displacement is greater than 10 meters.

8 points: Travels 3-5 m in a straight line. Final displacement is between 5-10 m.

6 points: Travels 2-3 m in a straight line. Final displacement is 5 m.

0 points: Final displacement is less than 5 m.



10 points: Demonstrates excellent conceptual understanding of the physics principles behind a mousetrap car. Applies this understanding in conducting an excellent, meaningful investigation.

8 points: Demonstrates good conceptual understanding of the physics principles behind a mousetrap car. Applies this understanding in conducting a good investigation.

6 points: Demonstrates minimal understanding of physics principles behind a mousetrap car. Conducts a basic investigation.

0 points: Demonstrates poor conceptual understanding of the physics principles behind a mousetrap car. Does not fully apply this understanding in conducting a meaningful investigation.



10 points: Completes the project journal honestly and clearly.

8 points: Completes the project journal vaguely.

6 points: Partially completes the project journal..

0 points: Does not complete the project journal.


 Journal & Investigation Format