Grade 5 · Science · Lesson 37

Bridge building & forces

Bridges are structures engineers design to carry loads across a gap. Every bridge has to handle two main forces: compression (a squeezing push) and tension (a stretching pull). Different bridge shapes spread these forces in different ways. In this project lesson you will build a small model bridge, test how much weight it can hold, and look at how shape affects strength.

What this lesson teaches

1Identify the main forces that act on a bridge
2Compare beam, arch, and suspension bridge designs
3Explain why triangles make truss structures strong
4Plan a fair test for the load capacity of a model bridge

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