Mrs. Walker's Mousetrap Car Project

Mike's Award Winning Creation
(It's an old picture, but I love the fly swatter!)

Click the above link to see a winning mousetrap car!

The challenge is to build a car that is powered by the spring of a single mousetrap. Rat traps are not allowed. The car cannot be powered by CO₂ cartridges, rubber bands, elastic, or anything other than the mousetrap sold to you (at cost) in class. This will ensure that everyone starts on a level playing field if all are using the same type of mousetrap. DO NOT alter the mousetrap spring by adding additional turns. This will disqualify your car.

It is suggested that you do not glue the trap on your car. If it breaks, you will have to begin the project all over again. Fasten the trap on with screws, bolts, twist ties, or string instead. Most traps have not broken. The wire overlapping the lever arm has simply slipped off. Re-attachment is simple. The trap base is hard wood, so you will have to drill a hole first. If you take notes in class on the day we brainstorm car design, the project is really quite simple! Avoid procrastination.

We have full confidence in your ability to ace this assignment. You will have the opportunity to view example cars in class, brainstorm car designs in class, watch last years competition, consult with your teacher, and bring your car in early to try it in the science hallway. The photos, video clips, and links provided below are intended to encourage your own creativity and success. They show both good and bad examples for educational purposes. These pages are intended to also benefit students who were absent from class on the day we discussed how to build a car. (Thus, no tutoring was missed relative to the project.)

You will be graded as follows. We have been studying energy and translational motion. Therefore, the potential energy of a mousetrap car is contained in the spring. The energy must be changed from potential to kinetic energy (or motion) in order for you to receive any points. It is not enough simply to have built a car. Your car must move! Your grade is determined by having followed the directions given you in class and in this rubric. Your car must be original to you. You must have built it. You may not use a kit purchased on-line or at a local hobby store to fulfill this assignment. This will earn you an F. (Beware: We have photographs and videotape of all former cars from other classes and other teachers. Trying to pass off a car from a prior year will earn you an F. We also have pictures of all available kits.) Part of the assignment is having met the due date given by your teacher. Building the car early will help you to avoid unforeseen circumstances. This assignment is an application of what was learned when studying energy. It's one of the really fun parts of this course! So please enjoy it!

Mousetrap Car Grading Sheet Name:____________________

1.     Distance the mousetrap car moved in meters:    ___________

                    Each category will increase 1 point per 10th of a meter.
                    No Car brought to class = 0 points (There is no partial credit or time extended for late assignments.
                    All cars are due on the due date.)

                    No Car = 0 points
                    Car doesn't move 0 points
                    1 meters = 10 points
                    1.5 meters = 15 points
                    2 meters = 20 points
                    2.5 meters = 25 points
                         3 meters = 30 points
                    3.5 meters = 35 points
                    4 meters = 40 points
                    4.5 meters 45 points
                         5 meters = 50 points
                    5.5 meters = 55 points
                    6 meters = 60 points
                    6.5 meters = 65 points
                    7 meters = 70 points
                    7.5 meters = 75 points
                    8 meters or more = 80 points
                    Add 1 point for each 0.10 meters between categories. For example: 7.4 meters is worth 74 points.                                                                                                                                                                                                 Total Points_____

Longest distance in class 10 bonus points
Longest distance in all classes 20 points

Bonus Points______

2. Speed over eight meters

        Distance Trail 1________            Trial one time______sec.                 Speed_________m/s
        Distance Trial 2________            Trial two time______sec.                 Speed_________m/s
        Distance Trial 3________            Trial three time_____sec.                 Speed_________m/s

                    Fastest in class 10 point bonus.
                    Fastest in all classes 20 point bonus.
                                                                                                            Bonus Points______

3. Most creative car as voted by each class.
(15 points) Bonus Points______

4. Thirty point (30) limit for bonus points earned
by any one individual. Subtract bonus points if necessary.

Deduct Points______

<> Total Points _______

If you build a car from a commercialized kit you will be assigned an "F". You are expected to be creative and build a car from scratch for this project. Do NOT purchase a kit or use any part of a kit with pre-cut pieces from a hobby store. Do not shop on-line to use a kit or any part of a kit. Do not use parts from a brother or sister's car if you cannot verify that they did not come out of a kit. Save your receipts in case they are needed to verify the originality of your car. Again...if in doubt, show the parts to your teacher and ask. This project is considered an assessment. Therefore if you deviate from the teacher's verbal and/or written instructions regarding kits, you will be in violation of the academic honesty section of the student handbook and will receive zero credit for this project.

Use all the links and information listed below. A little research goes a long way. Do not use constructs, erector sets, or legos to build your car. You can buy aluminum, brass, or wooden rods. Parts can be purchased separately. The best cars are home made. It's best to ask your teacher first, so that your car isn't disqualified. If in doubt about those parts, please ask. It is your responsibility to ask for clarification if you need it. Don't assume. Do not use cars from 8th grade or ones that were previously graded in wood shop. Previous Boy Scout "Pinewood Derby" cars would also be unacceptable. Do not try and pass off a siblings car or friends from a prior year. The consequence will still be an F.

If you begin early, the project will not be difficult. Do not simply build something that you saw on youtube. Some have tried to copy such a car and it didn't work. Again, listen to your teacher while they are coaching you in class on this assignment. Take notes. Research on your own. Do not wait until the last minute. Start early! Test your car before the due date. You should bring it to school and take advantage of the long hallways for your test run. If you do not have a functioning car on the day they are due, you have not meet the requirements. There will be no time extensions. You will not be given time in class to fix a car that is not working on the day that they are due. You will not be able to fix a car after school on the day it is due if it is not functioning. All cars are due at the beginning of your particular class period. You had two weeks to complete this assignment and to test your car.

The movie reel was a great idea.

This car is the one in the video clip listed above.

Cute, but don't block the lever arm. The theme is a "mousetrap" car.

This was an "A" ... all the way down the hall.

                                                                                                                                                                               Physics Scholar from Ontario Canada:
                                                                                                                                                                                             "International Studies"
                                                                                                                                                                                    (Tracked Mrs. Walker through e-mail)

Some of the challenges you will need to overcome are gravity, friction, and weight distribution. The first decision you will need to make concerns your ultimate goal. Is it speed or distance? Each will require a different lever arm length and tires. It is best to experiment with several different lengths for your lever arm. When considering speed, think in terms of a small lightweight car with a short lever arm that snaps quickly. The mousetrap imparts the energy to the car quickly. Think foam or rubber tires. The car travels at a rather high speed and coasts to a stop. Make sure your car travels the 5 meter minimum. This is harder to do when building a car for speed. If distance is the goal, you may consider extending the length of the lever arm. This slows the speed of the car, but allows the axle to be pulled for a longer period of time. Check the links below to discover the perfect lever arm length. Experiment with different types of string and wheels. It really does make a difference.

Listed below are a few of the links I discovered that include tips on how to build a mousetrap car. If you are unsure about a particular design, ASK your teacher! The links are not provided for you to copy someone else's car, but to stimulate your thinking.

http://www.docfizzix.com/mouse_trap_cars_tips.htm

You'll find good tips on Doc Fizzix’s site on how to correct problems that arise after you have finished your car. His tips will allow you to decide if you want to build a car with speed as your goal or distance. DO NOT BUY A MOUSETRAP CAR, WHEEL KIT, or WHEEL SPACER KIT (THE BLACK PLUMBING WASHERS) FROM THIS SITE OR ANY OTHER WEB SITE OR HOBBY STORE SELLING SUCH. DOING SO WILL WIN YOU AN “F” ON THE PROJECT. Do not purchase one locally. Do use this site to problem solve once you've built your car and need to tweak it. Most of the information in Doc's books is available on-line on the docfizzix web site. This is where to go for help problem solving a car that doesn't move. You can usually get the books through inter-library loan too.

Don't use kits or any parts from kits. Save all receipts.

Instead, use these:

http://www.mousetrapcar.com.au/

Here are some additional tips that will help you to understand how the car works and what to do to build one. Buy a book, not a car kit.

http://www.instructables.com/id/Mouse-Trap-car/
Actually, this car will not go very far. The design isn't as good as you might think. (I've seen several on youtube that are duds too. I've included this link to show you that you can't believe everything that you read on the Internet. So rather than trust someone else with your grade, why don't you just give it some thought for yourself? You can do it! The one thing that I do like about this information though, is the fact that you don't have to spend a bundle to make a functioning car. You can use simple things that you already have around the house. Students tend to think that the only acceptable wheel is a CD. This isn't true. Think round! Paper and plastic plates are round. There are plastic lids, records, wire spools etc. Large 33 1/3 records do need weight reduction to be effective though. The Dremel is a crafter's friend if you own one.

http://cpphysics.homestead.com/mousetrapg.html

Many of the links on the above mentioned link take you to Doc’s web site. However, there are some excellent photos of students with their finished cars. You may find some additional ideas here.

Pictures of cars displayed at Plainfield High School:

Consider wheel diameter carefully! Light weight is a good idea. Simple and light.

Cool lever arm, but heavy body. Electrical tape for traction. Awesome spinners !
Lengthen body to improve car.

Do not use these! Painted immovable wheels! Beware. Mr. Chissus' Mousetrap Car (front)

A car built from constructs, legos, or erector set pieces is unacceptable. Ask your teacher if in doubt.

Creativity can earn extra points!                Tread is good for traction.                  Think "Green". Love the paint job!
                                                              These wheels were too small though.        Longer bodies will use longer lever arms.

Plywood is heavy. Small wheels yield short distances. Research the length of that lever arm.

Choose lighter materials.

Length can have advantages, it all depends.
More weight requires more energy to move the car.

The body was a paint stick. Mrs. Walker's 1st car. Insulation is light and was clever.

Holes drilled to lighten the car. Body was too heavy, but awesome wheels.

Metal frames are okay too. Research gear advantages. "Be-dazzle" that car for those creativity points.

This car was graded twice. It's not a good idea Einstein would be proud! An art scholar's car!
to try and recycle a car from a previous year. It
earns an "F" the second time around.