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Can you build a bridge that holds 100 pennies using one sheet of paper and up to five paper clips?
A bridge must support its own weight (the dead load) as well as the weight of anything placed on it (the live load). Your bridge must span 20 cm (8 inches). The sides of your bridge will rest on two books and cannot be taped or attached to the books or the table.
(per group of two)
- 20-30 minutes
- plain paper
- 5 paper clips
- ruler
- 2 books or blocks
- at least 100 pennies or other small weights
- scissors
Describe how you think the bridge should be constructed in order to support its dead load plus the live load of the pennies.
- Discuss possible ideas with your partner before you start building. What can you do to the paper to make it stronger? When you have decided on a design, construct your bridge.
- Place the bridge across two supports 20 cm apart. Remember that the space below the bridge must be free of obstacles to boat traffic!
- To test your bridge, load it with pennies one at a time, until it collapses. Record how many pennies your bridge supported.
Describe how well your bridge supported its dead load and the live load you placed on it. Was the bridge as strong as you thought it would be? Where did the bridge fail? How could you redesign the bridge to make it stronger?
Once you have succeeded in building a bridge strong enough to support the load of 100 pennies, test it to see if it can withstand the load of an earthquake (shake the table) or wind gusts (use a fan). If not, redesign your bridge to make it stronger, and test it again. You can choose one more material to help strengthen the bridge.
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