9.4 Bridge Building

See how shape changes a bridge

Science Buddies: Paper Bridges STEM Activity · 2:06. Watch how the same material is folded into different shapes, then tested.

Predict: which shape will carry more load? Then compare two models using the same paper, span and load position. Record the result before changing one feature.

This experiment helps you investigate the structural part of your bridge. Your moving bridge will also need separate tests of its pivot, friction, alignment and control.

Build, test and improve a bridge

Design a bridge for an agreed span and load. Start with small models, test what happens, and use the results to improve your design.

This topic covers

• Investigate how shape, materials and connections affect a structure.

• Compare loads, stability and alignment using models.

• Build, test and improve a bridge against agreed requirements.

• Record what changed and what the test showed.

• For a moving bridge, investigate the pivot, movement, friction and control separately.

• Explain how structural and mechanical parts work together.

Plan your evidence

1. Agree the span, load, user needs and safe test method with your teacher.

2. Sketch two options. Label materials, joints, supports and the path of the load.

3. Build a model. Keep the span and load position consistent when comparing designs.

4. Record the load, bending, movement and where failure starts. Photograph the test.

5. Change one feature, such as a brace, joint or material. Repeat the same test and explain the difference.

Moving-bridge investigation

To investigate the full mechatronics strand, add a teacher-approved moving-bridge model. A fixed bridge alone does not demonstrate movement, friction or programmable control.

• Test the pivot, alignment and friction with power disconnected.

• Identify the structural, mechanical, electronic and digital subsystems. Draw how energy and control signals move between them.

• Use suitable teacher-approved drive components and supply. Plan clear open, moving and closed states before programming.

• Compare predicted and observed movement. Check stability, unwanted rubbing and reliable connections.

• Define how movement is stopped and tested safely. Use measurements to justify one improvement.

Curriculum connections

Select structures, mechanisms and materials; explain forces and stability; use annotated sketches and system diagrams; record fair tests; diagnose structural and mechanical faults; refine alignment, movement, friction and reliability. The moving model extends this to coordinated mechatronic subsystems.