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← Summer Solo-Science

Week 10Releases August 24

Paper bridge load test

The season finale: design a paper bridge that holds the most coins, using shape — not extra material — to make it strong.

For you to do

You'll bridge a gap between two book stacks with one sheet of paper and see how many coins it holds. Then you'll redesign — folding, arching, rolling — to hold far more, with the same single sheet.

Grown-up help

All on your own.

The challenge

The rules (constraints)

Same gap, ONE sheet of paper, and only a little tape every time. Those fixed limits are your **constraints** — beat your old score without breaking them.

Set the books about 15 cm apart. Lay a flat sheet across as your first **prototype** and gently add coins until it sags. Record the number.

Redesign for strength

  • Try folding the sheet into a fan (accordion) of ridges.
  • Try an arch, or rolling tubes.
  • Each new shape is an iteration — log the coins it held.

What's happening

A flat sheet bends because the **force** of the coins isn't spread out. Folds and arches turn that force into pushes along the paper, which it resists far better. The **trade-off**: a tall fan is strong but uses width you might need for the road. Engineers chase the best design inside fixed **constraints** — exactly what you just did.