Lesson Overview
Students apply the engineering design process to design and build a bridge using limited materials that can hold the most weight. They test, identify failure points, and iteratively improve their designs — experiencing real structural engineering concepts like load distribution, tension, and compression aligned to NGSS ETS1.
Learning Objectives
Students will be able to:
- Apply the engineering design process: define, ideate, prototype, test, iterate
- Identify compression and tension as forces in a structure
- Test a bridge design against defined success criteria
- Use data from testing to improve a design and justify changes with evidence
Lesson Phases (5E Model)
- 1Show images of 3 famous bridges (suspension, arch, beam) — ask: 'What's different about how they're built?'
- 2Quick demo: hold a flat index card between two stacks of books — add pennies until it collapses. Ask: 'What failed?'
- 3Announce the challenge: Build a bridge that spans 20 cm and holds as many pennies as possible — using only the materials provided
- 4Review the constraints and success criteria together as a class
Assessment Strategies
Design Blueprint
Evaluated for clarity of plan, labeled materials, and evidence of constraint awareness
Test Data Sheet
Scored on completeness of data and quality of failure analysis
Written Reflection
Holistic score on use of evidence and engineering vocabulary in reflection
Extension Activities
- →Research the engineering behind a specific famous bridge failure (Tacoma Narrows, 1940)
- →Calculate the weight-to-material ratio — which team's design was most efficient?
- →Use the Engineering Academy Bridge Builder simulation to test virtual designs before building
- →Challenge: Can you build a bridge using only paper and tape that holds a textbook?
At a Glance
Grade BandGrades 3-5
Duration75 min
Group SizeTeams of 3–4
DifficultyIntermediate
SubjectEngineering
Lesson Model5E Instructional Model
Materials
- Popsicle sticks30 per team
- Index cards10 per team
- Tape (masking or scotch)60 cm per team
- String or twine50 cm per team
- Paper clips10 per team
- Ruler1 per team
- Stack of pennies or small weights for testing50+ per class
- Design planning sheet1 per student
- Test data recording sheet1 per team
Key Vocabulary
- Compression
- A pushing force that squeezes or shortens a material
- Tension
- A pulling force that stretches or lengthens a material
- Load
- The weight or force that a structure must support
- Iteration
- Repeating a process to improve it based on what you learned from testing
- Constraint
- A limit or restriction on a design (like how much material you can use)
Digital Tools
- →Engineering Academy — Bridge Builder Simulation
- →Engineering Academy Lesson: Structural Engineering Basics
