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# Triangles: Designing a Newspaper Chair

Media Type:
Video

Running Time: 4m 21s
Size: 13.0 MB

or

Source: ZOOM

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Once it's been read, there's often little more to do with the daily newspaper than to add it to that towering stack of recyclables we collect each week. In this video segment, however, the ZOOM cast demonstrates how innovative design can turn this otherwise flimsy material into a relatively solid piece of furniture.

Background Essay

One of the most common shapes in structural design is the rectangle. All around us, from floor to ceiling, in doorways and in window frames, columns and beams are attached at right angles to form rectangles of different dimensions. Despite its prevalence, the rectangle is not a particularly strong shape. The compressive force of a weight pushing down can easily cause a rectangle to deform -- to change into a parallelogram -- if the structure's joints pivot. This means that all of a square's stability is provided by the strength of joints.

In contrast, the triangle is an inherently strong shape. It cannot be deformed unless the length of a side changes or one of its joints breaks. This makes the triangle one of the most rigid and stable shapes used in construction today. In fact, rectangular parts of structures can be strengthened by adding supports that form triangles within the rectangle, either at the joints or diagonally across the entire figure.

In building their newspaper chair, the ZOOM cast members made good use of triangles, connecting joints with diagonal supports that strengthened and stabilized the square shapes they started with. In addition, the newspaper tubes they used to build their chair were both strong and easy to make. Like triangles, tubes provide a great deal of strength. At the same time, they are much lighter than supports made of solid material.

Discussion Questions

• Why do you think the ZOOM cast members used triangles? Explain your answer using sketches to show the forces involved.
• The ZOOM cast members used their triangles in a specific design. What was this design? Can you think of other designs that might be stronger? If so, describe them and explain why you think they will be stronger. If not, explain why not.

• Standards

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