Engineering design challenge: Strengthen a paper bridge
Courtesy of: Engineers Nova Scotia
In this quick activity, participants will test how many pennies a flat paper index card bridging the gap between two stacks of books is able to support. Then, participants alter the structure of the same card by folding it accordion-style and retest by again stacking pennies on top. Participants look for a relationship between the number of folds and the number of pennies the card can hold by creating a scatter plot.
Build the strongest possible bridge from one index card.
Materials you will need:
- Books for stacking
- Index Cards
- Introduce the activity, explaining the goal is to build the strongest possible bridge from one index card. Demonstrate how many pennies a plain index card can hold and write that number down on the white board. Explain that they can manipulate the index card but cannot add anything to it.
- Give each girl books, a few index cards, and some pennies.
- Indicate how long they have to design the strongest bridge.
- When the time is up have girls raise their hands if they think they have the strongest bridge.
- Ask the girls who raised their hands to count how many folds they made in their bridge and how many pennies it could hold. Add these to the white board.
- Ask the group the following questions:
- What did you do to your bridge?
- What shape did the folds make?
- What made your bridge stronger?
- What do you notice about the numbers on the board?
- Did you notice anything else about building the bridges?
- Address the following learning points:
The more folds = the stronger the bridge.
“If there is a single most important shape in engineering, it is the triangle. Unlike a rectangle, a triangle cannot be deformed without changing the length of one of its sides or breaking one of its joints. In fact, one of the simplest ways to strengthen a rectangle is to add supports that form triangles at the rectangle's corners or across its diagonal length. A single support between two diagonal corners greatly strengthens a rectangle by turning it into two triangles. Triangulation of material, adds strength by eliminating lateral movement.” – Schoology