Lesson 1: Why do we need bridges?

This activity revisits learning from Design and technology, Year 2, Structures: A chair for a bear: Lesson 3: How does the thickness of a material affect its strength? and Design and technology Year 3, Structures: Helmets: Lesson 3: Strengthening techniques to recap key learning about stiffness and flexibility.

Pair the children and show the Presentation: Material thickness and strength. Point out the first image, showing a bridge (a structure built over an obstacle to allow crossing) made by placing a piece of paper over a gap. Explain that in the second image, the paper has been folded lengthwise twice.

Ask the children to predict what will happen to each bridge when a weight is placed in the middle and explain their reasoning to their partner.