Month: December 2016

Design Challenge: The Foam Wood Derby

I’ve always wanted to run a super face paced pinewood derby style race. As I designed some simple, messy projects for the 8th grade as sort of fun one off projects, I decided to make the idea a reality.

The design is simple. Each group (or individual if your group is small enough) has two deliverables. A car carved out of foam, and a top and side drawing of the car. They get a basic set of materials. A block of floral ‘wet’ foam, 2 axles and 4 wheels. And they get a simple set of tools. Basic measurement tools, speed squares and surform carving tools.

I introduced the challenge quickly, then let the students loose. To avoid having students completely destroy their blocks instantly, I made the drawings a prerequisite to getting the carving tools. The drawings could be simple, but I required a detailed full scale engineering style drawing.

Once the drawings were approved, they were off to the races. However, floral foam is mess. Super messy. I had complaints of allergy like irritation, the foam staining white shirts, dust in their eyes. All sorts of things. However, after stressing caution, using aprons and generally being more mindful, those complaints dropped off. Perhaps this would be a good project to do in a larger space or even outside.

With the designs carved, students were free to attach their axles and wheels. I could have stopped the groups and stressed the importance of being patient with this step, being precise and ensuring straight and square axles. However, I let them at it, though I did stress that our speed squares would be a great benefit to this step.

The axles and wheels came from Pitsco. Sure, you could 3D print wheels if you have the time, but laser cutting in wood was too soft and acrylic was too brittle. A soft thermoplastic is what these wheels need to be made of, and at $0.15 a piece, it was worth avoiding the headache.

Finally, we race. I used a scrap board at first…but we really needed lanes as cars continued to collide with one another. I used some foam board to make short walls hot glued to the edge of the board. Problem solved.

A simple single round elimination was enough to have a good final race, while minimizing the winners vs losers. You can even enforce a ‘When you lose, you become a cheering squad member of the team that beat you’, ensuring an exciting final race while making all of the students feel a part of the races through the end.

Finally, have students reflect on the process. I had a short discussion, then had students go and post to Seesaw. I got lots of really awesome reflections, lots of great critical thoughts, some great doodles and awesome photos.

Looking back, this little design challenge went pretty well. The kids loved it, it was inexpensive (~$1.50 per group), and was quick to run. In the future I think it could be slowed down to highlight the engineering drawings in more detail, perhaps print wheels, and focus on nice and straight axle holes.

Part Cost Cost / Kit Source
Floral Foam (72 when halved) 35.50 (price fluctuates on amazon) 0.50 Amazon
Pitsco Axles (100) 6.50 0.13 Pitsco
Pitsco Wheels (100) 15.50 0.62 Amazon
TOTALS 57.50 1.25

Surform Tools – $2.99

Speed Squares – $2.99