My fellow 8th grade science teacher colleague introduced me to the idea of designing and building mousetrap cars as a cumulative project for our force and motion unit this year. She had done this project with a group of students 20+ years ago and she said she wanted to try it again because she remembered it being so great.
We had tons of fun facilitating this project and our students LOVED it. Student-designed mousetrap cars are a great way to incorporate engineering and design principles into your physics unit!
Student groups will design, construct, and race their mousetrap cars while learning about energy transfer, simple machines, and speed! This is a great way to end the year in science, too!
I am providing a FREE DOWNLOAD of this resource, so be sure to scroll to the bottom to grab the freebie!
The Gist and the Materials
When I first heard about this type of project, I assumed that the mousetrap would be snapping closed to power the car forward. However, this is not the way that a typical mousetrap car works!
Instead, a lever (a chopstick) is taped to one side of the metal part of the mousetrap. The lever has one end of a fishing line taped to the top of it. The other end of the fishing line is attached to the back axle of the car.
In order to ‘power-up’ the car, you will need to turn the back axle using the wheels so that the fishing line winds up in the center of the back axle. When you place the car on the ground, it will be propelled forward as the fishing line is released gently from the back axle, spinning the back wheels. The lever will slowly return to its resting position.
See these resources to help with understanding the way that a mousetrap car works!:
- 1st Place Mousetrap Car Ideas You Tube Clip
- Olivia’s Physics Blog: Mousetrap Cars
- CSU Fresno Mousetrap Cars Packet
I suggest having the students work in groups of 3. These are the materials that you will need for each group of students:
- 1 mousetrap
- 2 wooden paint stirrers, 12”
- 1 rectangle of balsa wood
- 2 plastic straws
- 2 pairs of wood chopsticks
- 4 rubber washers (1/4”)
- 4 CDs
- 1 zip tie
These are the materials that you should have available for everyone to use:
- fishing line
- masking tape
- duct tape
- glue
The Four Phases
This project has four phases: the Introduction and Design Phase, the Construction Phase, the Race Day, and the Self-Assessment and Reflection Phase. I have detailed the components of each phase below…
The Introduction and Design Phase
- Introduce the project by showing a video clip of a mousetrap car (I used the clip from the top link in the section above).
- Hand out the project directions sheet and go over the basics of the project. Show the students the materials that will be provided and explain that they can bring in materials from home if they’d like to try different design ideas. For example, a student may have different wheels from an old toy car that they’d like to try, or a student may have an object they’d like to try to use as a longer lever.
- Put the students into their groups or allow them to choose partners.
- Post some Mousetrap Car resources on your Google Classroom and allow them some time to brainstorm design ideas. I suggest early on that they try to either win for speed OR for distance, but not for both! The long-distance cars are not necessarily fast! The speed cars don’t necessarily go that far! This differentiates the activity so that all of the groups don’t end up with the same exact car design.
The Construction Phase
Depending on the age of your students, allow about three 45-minute class periods for students to construct their cars. They will start to get really into it so you will need to set a date for the Race Day to give them a deadline! Your students can experiment with three-wheeled cars, long levers, fishing line attachment strategies, lengthening the body of the car, and lots of other variables!
Race Day!
- My suggestion is to set up a race track in a hallway of your school. My race track was 9 meters long. I taped 9 meter sticks down the hallway in a line and used masking tape to clearly mark the half-meter and full meter marks along the track.
- Depending on the number of cars you have to race in a class, you can race them one or two at a time.
- Pass out the Race Day sheet and instruct the groups to keep track of both their own car’s data and the other groups’ data. This will help everyone to pay attention!
- When it’s a group’s turn to race, you will need a stopwatch. Either operate it yourself or put it in your students’ court and have a student from the group time the car while another student winds up the car at the starting line.
- Keep a LEADERBOARD to showcase the fastest and farthest-running cars throughout the day!
Self-Assessment and Reflection
This is an important part of the project to give the students the opportunity to reflect. Honestly, some of my students’ cars didn’t end up working at all. This was due to complications with the designs, ineffective group work, being off-task during construction days, using too much tape/glue and ruining the mechanics of the design, etc. I still wanted the students to reflect on what good things happened and what they learned. This part ties the physics back in, too!
You can grab a FREE DOWNLOAD of the MOUSETRAP CAR PROJECT! This package includes a Project Overview, a Design Proposal/Brainstorming page, a Race Day Data Tables page, and a Self-Assessment and Reflection page. I have also included award certificates for the fastest car, farthest-running car, and most innovative design, as well as a ‘blank’ certificate in case you have other award categories for which you’d like award your students!
I hope you and your students have a blast doing this project! If you do, I’d love to hear about your success in the comments below!
If you are teaching a Motion and Forces unit, you may be interested in this bundle of resources:
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