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What to do:

Cut cardboard strips and use staples to make a square and a triangle as shown. Try pulling the sides of these shapes. What do you notice?

Build a box-shaped framework as shown, using cardboard strips, staples, and tape. Hang the cup by a thread from the center of the framework. Place the two books 12" apart and put the framework evenly between them. Measure the height of the of the center of the framework. Put a coin in the small box and measure the height again. Do this a number of times and write down your measurements. Can you make the framework collapse completely?

Now make a triangular framework as shown. Repeat the experiment and compare the results. Which framework is stronger? Can you suggest why?


Taking it further:

Explore ways of making the box-shaped and triangular frameworks stronger. Try loading them in various ways to find if they have any weak spots.