Polygons and Popsicle Trusses
Students learn about the role engineers play in designing and building truss structures. Simulating a real-world civil engineering challenge, student teams are tasked to create strong and unique truss structures for a local bridge. They design to address project constraints, including the requirement to incorporate three different polygon shapes, and follow the steps of the engineering design process. They use hot glue and Popsicle sticks to create their small-size bridge prototypes. After compressive load tests, they evaluate their results and redesign for improvement. They collect, graph and analyze before/after measurements of interior angles to investigate shape deformation. A PowerPoint® presentation, design worksheet and data collection sheet are provided. This activity is the final step in a series on polygons and trusses.
Students analyze the different polygon performances in truss structures they design, build and test.
To design strong, stable and safe bridges, engineers consider many factors. Foremost, they want their truss designs to adequately support the bridge and its expected load. They ask: Does it make sense to build? Is it strong? Is it safe? What will it look like? What does it cost? In this activity, students act as civil engineers following the steps of the engineering design process to design and create miniature truss bridges that they subject to compressive load testing—which presents an opportunity to experiment with their own creative compositions of geometrical shapes—just as real-world engineers do.
After this activity, students should be able to:
- Explain why a triangle is the strongest shape and integrate this knowledge into the design of a truss bridge structure that they subject to loading tests.
- Explain how the deformation of a shape affects the sum of its interior angles.
- Practice following the steps of the engineering design process when designing truss/bridge structures.