Build a Bridge
Build a paper bridge that holds a stack of books. Then build a better one.
1 week🔬 Science🔢 Math✏️ Writing
What you need
- A4 paper
- sticky tape
- two piles of books to span
- coins or small books to load it
Nothing to buy and nothing to print — if you do not have one of these, swap it for whatever you do have.
The steps
Day 1
The flat bridge
Lay one flat sheet between two book piles 20cm apart. Add coins until it fails. Record the number.
🔢 Write the number down
Say this: “Failure is the measurement. We want to know exactly when it gives up.”
Day 2
The folded bridge
Fold a sheet into a concertina and try again. Same gap, same coins.
🔢 Write the number down
Day 3
Your own design
Design a third bridge. Draw it before you build it.
🎨 Draw it
Day 4
Test and record
Test your design. Put all three results in a table.
📊 Make a chart or table
Day 5
Explain it
Write a paragraph saying which held most and WHY the shape made the difference.
✍️ Write a few sentences
How to score it
You score this, not us. Pick the description that actually matches what they did.
Fair testing
- 1. Changed several things at once
- 2. Kept the gap the same
- 3. Kept gap and load method the same
- 4. Kept everything the same except the shape, and said so
Recording
- 1. No numbers
- 2. Some numbers
- 3. All three recorded
- 4. All three in a table with units
Explaining
- 1. Said which won
- 2. Said which won and by how much
- 3. Explained using the shape
- 4. Explained using the shape and connected it to something real
With more than one child
Younger children build and load; older ones run the table and write the conclusion.
What goes in the portfolio
Three bridges, a table of how much each held, and a paragraph explaining which shape won and why.