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Build a paper bridge
4+ hours
Design and build a bridge that can hold 5 pounds over a 20 inch gap using only paper and tape.
Learning connections

Design and build a bridge out of paper that spans at least 20 inches and can hold 5 or more pounds of weight.


  • You can only use paper and tape to build your bridge.

  • Use at most 30 pieces of 8.5" x 11" paper

  • The bridge must not be attached to anything. You must be able to pick it up and place it down over the gap without taping it to the edges of the gap or supporting it from underneath.

  • The 5 pound weight must be supported for 30 seconds without the bridge collapsing.

Dig deeper
Develop estimation skills

Example project:

Paper experiments
20+ minutes

To get started building a bridge from paper, play with a few ways of making a piece of paper better at holding things up.

Step 1: Try making a simple and short bridge from a single piece of paper.

Paper bending

Step 2: Roll a piece of paper into a tube, and experiment with folding it into different shapes to see which shape is strongest.

Strength of shapes
Organizing the experiment
Design and build
3+ hours

Using what you've learned from your experiments, come up with a design for your bridge and build it!

Forming the joints of your bridge — where two pieces of paper are attached together — can be one of the biggest challenges. See the resource on joint design if you'd like help with this.

Take photos as you go, including of any designs you draw, prototypes you make, your building process and the final completed bridge.

Communicating ideas
Engineering drawingsOpen Joint design and constructionOpen
Test and iterate
20+ minutes

Gather 5 pounds of weights to test your bridge with.

While recording a video, place the weights on the center of your bridge.

If you need a platform to place the weights on, you could use a small book as the base that sits on the bridge to distribute the weight more evenly.

If it fails the first time, that is to be expected! Take note of how it failed and iterate on your design until you get it to work. Document and share your iteration process so others can learn from you try.

Encouraging iteration
Keep it going!
Making 5 pounds

2 cups of water is about equal to 1 pound. Can you find a way to seal enough cups of water in one or more containers to make a total of 5 pounds?

To place your weights on your bridge, it may help to use a small book to distribute the weight more evenly.

Take it furtherOpen