Due: Wednesday 9/7/16, Thursday 9/8/16
Students will collaborate to solve an engineering problem of how to make the strongest paper ring from only a sheet of paper, a rubber band, and a short strip of tape.
- Collaborate in teams to produce paper ring design ideas
- Engineer and construct paper rings from a limited set of materials
- Test paper rings for strength by applying horizontal tension forces
- Evaluate paper ring design decisions
Discrepant Event: How does form follow function?
In the discrepant event, we examined the strength of paper through 3 various designs: triangular prism (triangle tube), rectangular prism (square tube), and cylinder (circle/round tube). In the end, the cylinder was able to hold up the most weight while the other designs collapsed under the weight of only 2 tape rolls.
Many of you were able to identify how the "roundness" of the cylinder was able to hold up the most weight. Some of you observed that the other shapes started to buckle first at the edges.
The design or intentional shape of the paper cylinder was crucial in its ability to hold up the most weight.
How does the roundness of the cylinder allow it hold up the most weight?
Constructing and Testing Design Products
After collaborating in groups and discussing design ideas, we tested our design products. Testing involved attaching a paper ring from each group with climbing carabiners (metal rings). The rings alternated between paper and metal. Rope was attached to each end and force was slowly applied to ensure that each ring was equally tested until the first one broke. The first ring to break earned 1 point, the second ring to break earned 2, and so forth. The final surviving ring from each round was saved for a final testing round which was worth double the points. The team that had the most points earned extra credit on the lab.
Look at the winning rings. These were able to withstand the force up to 6 students attempting to pull them apart. What do you notice about them that allowed them to withstand so much force?
Period Final Results
Cross-Disciplinary Connection: Human Femur
Cylinders are often found in natural structures such as our own femurs (thigh bone). The circular objects in the images below are cross-sections or cut-outs of the femoral shaft (long middle part of the bone). How does the shape of the femoral shaft help the femur do its job of holding up our weight and taking on the forces of walking, jumping, and running?