A grading rubric for a balsa bridge project
A simple teacher rubric covering design, build quality, testing, analysis and communication, with scoring that rewards learning, not only the highest load.
Updated · 1 min read
Short answer: grade the thinking, not only the load. A bridge that breaks early but is well explained can show more learning than a lucky strong one.
Suggested categories
| Category | What to look for |
|---|---|
| Design | A clear plan with reasons, pushed and pulled members identified, rules met |
| Build quality | Tight joints, thin glue, square trusses, within the mass and size limits |
| Testing | A safe, consistent test, with records of mass, load and first failure |
| Analysis | An explanation of why it failed, linked to design ideas such as buckling or weak joints |
| Improvement | A specific change, with a reason, and a comparison if rebuilt |
| Communication | A clear report or presentation, with honest sources and help |
| Teamwork and safety | Shared roles, safe handling, glasses worn |
Scoring tips
- Give most of the marks to design, analysis and improvement.
- Give only a small share to the final load, so luck does not decide the grade.
- Reward a failure analysis that is correct and specific.
- Check the efficiency calculation, not just the number. See efficiency.
See the lesson plan and the report outline.