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  Activity: Straw Shapes
Activities Index | Handout | Educator Ideas  

Which shape is more stable, a triangle or a square?
You'll test the stability of a triangle and a square by standing them on a table and pressing on them. The one that changes shape less is more stable.
Illustration of square shape versus triangle shape.

What You Will Need
• 7 drinking straws
• 14 paper clips

Make a Prediction
Predict which shape will be more stable. Why do you think so?
Try It Out
1. With your partner, build a triangle and a square from the straws and paper clips.
Illustration of two straws linked. To connect two straws, slip the wide end of a paper clip into the end of one straw. Hook a second paper clip to the first. Now insert the wide end of the second clip into a second straw. 
2. Compare the stability of the shapes. Stand each shape up and press down on the top corner. What happens? How much does each one bend and twist? How hard can you press down on each shape before it collapses?

Explain It
Compare the results of your tests on the triangle and square. Which shape was more stable? What do you think made it more stable? How might this shape be used in large structures? 

Build on It
• Can you reinforce the less stable shape by adding no more than 2 straws and 4 paper clips?
• Now that you know more about shapes, build the most stable structure you can using no more than 20 straws and 40 paper clips. How much weight can your structure support? 

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