1. Basic Instructions For the Mousetrap Car Competition
Team entry: 2 students required
Design
Mousetrap car construction and run
Communication
Technical report writing
Design drawings

2. Mousetrap Event Final Scoring
Total of the following scores
Mousetrap car performance (50 pts max)
Design drawing (25 pts max)
Technical report (25 pts max)
Total Max – 100 pts

3. Design drawing Title card (4” X 6”)
Team name
Team members names
Paper size (18” X 24”), 1” margins,16” X 22” actual drawing
Must show scale and units (use 1:1 and inches if possible)
Label all parts
Three views (front, side and rear)
Dimensions
Accuracy
Neatness (pencil and fully erase)

5. Technical Report Writing
Describe the design, construction and operation
Computer printed, 12 pt. Type, double-spaced
White, 8-1/2” X 11” paper, 1” margins
Maximum of 3 pages
Graded on
Outline
Organization
Precision
Sentence formation
Mechanics

6. Technical Report Organization
Cover page (required to contain)
Title
Names
Abstract (1/2 page summary)
Table of contents (1 page)
Introduction
Design
Construction procedure
Operation of the mousetrap car
Conclusions / Recommendations
Acknowledgements
Appendix (sketches, tables, charts etc.)
3 page maximum

7. Mousetrap Race Scoring2
Weight of Mousetrap
_________________
Weight of Car
Distance
_______
Length
Goal: Minimize weight
Minimize length
Maximize distance

8. Basic Instructions For Building A Mousetrap Car
This is a set of basic instructions and tips on how to get started building a mousetrap car.
Many other materials and designs are possible
Adapt the instructions to your needs and imagination.

9. Materials
Mousetrap
Chassis: wood scraps, balsa wood, ice cream sticks, stiff wire
Axles: wooden dowels, metal tubes (copper or brass), axles from old toys, ink pens, pencils
Wheels: Metal lids, CDs, wheels from old toys, other disk-shaped objects
Pull Cord: String, rubber bands or fishing line

10. Physics Concepts Friction
Friction is the resistance of motion between two objects. Most friction between the materials in your car reduce the amount of energy that is used to move the car, so it would make sense that you want to reduce that friction. However, you actually rely on the friction between your wheels and the floor to help your car move.
Another, less thought of, friction involved in the performance of your car is air resistance. Remember, air resistance acts against the motion of the car and therefore should be reduced to increase performance.

11. Physics Concepts Newton’s Laws
Newton’s first law is also known as the law of inertia. Inertia is an object’s tendency to resist change. The more massive an object is, the larger its inertia, and therefore the harder it is to change its motion. Newton’s second law is most commonly known in its equation form, F=ma. Both of these laws should show you that the more massive your car, the more force that will be required to move the car. Remember that, depending on the goal of the car, you may want the car to have some inertia so it will keep moving after the mouse trap has used all it energy. Keep these laws in mind while constructing your car.

12. Physics Concepts Rotational Inertia
Just like linear inertia deals with an object’s tendency to resist change of its linear motion, rotational inertia is an object’s tendency to change its rotational motion. The rotational inertia of an object depends on its mass and the distribution of that mass. Since the wheels of your car are the parts that are rotating, you may want to decrease or increase their rotational inertia.

13. Physics Concepts Energy
Energy can be defined as the ability to do work. Work is the applying a force to an object, and actually moving that object. If the object is not moved, no work is done. The goal of the project relies on efficiently transferring the spring’s energy to the car’s wheels. The concepts involved in the transfer of this energy rely on an understanding of simple machines. The trap acts as a lever to transfer the energy to the axle. The axle acts on the wheel as a second transfer of the energy. Finally, the energy is used to push the wheel against the floor, causing the car to move. Any friction or resistance in the transfer of energy, leads to a decrease in the efficiency of the machine and decreased performance. Keep the use of simple machines in mind as you design the car, the correct use of these machines will increase your performance.

14. Tips
Wheels: Old CDs make great wheels, but have very little traction. Stretch a wide rubber band around each wheel; the rubber band can even be glued into place.
Pull Cord: Your pull cord needs to be strong enough to withstand the forces exerted by the mousetrap spring. Fishing line, rubber bands (not legal in some competitions) or strong string work well. Winding the pull cord in the wrong direction makes the car go backwards; painting a small arrow on the axle as a reminder can help.
Alignment: A mousetrap car that always steers to one side will not be good for competition. Place shims (small pieces of scrap wood) in between the bushings or bearings of one or more of the wheels to align the wheels. It is very easy to do this with balsa wood.
Aerodynamics:
Keep the number of flat surfaces facing the front of the car down to a minimum. Sanding the body of the car smooth also helps cut down drag.

15. Hints for Better Performance
Reduce friction
Use lightweight materials
Amount of rotational inertia depends on the goal of the car.
Test the lever arm length and wheel size to determine the best for your type of car.
Experiment early and often

16. Possible Websites to check out for ideas
Possible Websites to check out for ideas. There are hundreds of sites on the Internet. Do your own research and use some of these if you need additional help. 1. 2. 3. 4. 5. 6. 7. 8. 9.
10.

17. Remember Your final score is the total of the following scores:
Score on technical report
Score on car design drawing
Mousetrap car race score
Don’t focus on the car race and forget the others!