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Buhl fifth-graders make toothpick bridges

Every May, ITD’s south-central Idaho office makes a point to break the bridges that Buhl Elementary School fifth-graders have painstakingly created. Rather than being seen as cruel or vindictive, the exercise is viewed with anticipation and wide grins.

The kids may not know it yet, but they are being introduced to engineering principles. ITD may not know it yet, but it is being exposed to the enthusiasm and creativity that will mark the next era of engineers, many of whom will walk the department’s halls in the future.
The idea behind this outreach is to promote interest in math and science. ITD makes the first presentation early in May. The kids are asked to turn 300 toothpicks and a few ounces of glue into bridges, and they are given design parameters (the bridge has to span six inches, can only be two inches tall and two inches wide).

Steve Tonks and Trey Mink review the bridge plans, rating them on design symmetry, dimensions, and constructability. Basically, is the needed information included on the design to enable a contractor to build the bridge?

ITD returns a few weeks later to test the weight-bearing capacity of the structures. The bridge that won this year held 34 lbs. before structural failure. Approximately 75 kids participated in this year’s challenge.

Pictured above: The weight-bearing capacity of two different styles of bridges are tested.

The top weight-bearing bridge, Mink recalls, was a structure built by a student 10-12 years ago. The actual capacity is unknown, however.

“We got to 100 lbs., but then the process of adding weight was stopped because the young man did not want his bridge to be destroyed.”