Students to Test Physics Laws by Destroying Bridges at Southern Nevada Model Bridge Contest at UNLV

Media Contact: Steve Leon, 702-293-8456
Paul Matuska, 702-293-8164

For Release: February 26, 2010

Would you submit a model bridge for destruction after you had labored for hours on its design and construction?

That is just what hundreds of students from more than 50 local elementary, junior, and senior high schools will do at the 21st Annual Southern Nevada Regional Student Model Bridge Building Contest on Saturday, February 27, at the Engineering College of the University of Nevada, Las Vegas (UNLV).

The students will test their math, physics and budding engineering skills by submitting their model wooden bridges for testing. Weighing less than one ounce, the bridges, built by individuals or teams, showcase the builder's skills, ingenuity, attention to detail and weeks of planning, designing, and building efforts.

"With great enthusiasm they watch this exciting and educational activity, as their bridges are destroyed in seconds," said Paul Matuska, a Bureau of Reclamation hydraulic engineer and long-time Bridge Building event planning committee chairperson.

"The objective of the contest is to find out the maximum amount of load or weight each bridge can take before failing," he said. "Or stated another way, we press on the bridge with a materials testing machine that uses increasing pressure to simulate weight until the bridge finally breaks. In past competitions, bridges have been tested to pressures equivalent to support weights as high as 350 pounds!

"The bridges are then ranked according to their 'efficiency,'" he added. We calculate this 'efficiency' by dividing the total weight the bridge supports before it fails, by the weight of the bridge.

"The machines we use are normally used by UNLV professors and students for the more technical purpose of determining the load-bearing strength of a specific material, or the minimum amount of lengthwise stress needed to pull that material apart."

All bridges must be designed and constructed according to strict standards. The students can use only the 3/32-inch- square cross-section basswood included in the kits supplied to the schools by the sponsors. The wood may be notched, cut or laminated in any manner, and fastened with any commonly available glue. But no other materials may be used in its construction.

In addition, a bridge cannot weigh more than 25 grams (just under one ounce); must be at least 300 millimeters (about 12.5 inches) in length, but not more than 400 mm (about 16.5 inches) long; cannot be more than 120 mm (about 5 inches) high, and no more than 80 mm (about 3 inches) wide.

The contest is jointly sponsored by Reclamation and the American Society of Civil Engineers in coordination with UNLV and the Clark County School District, Terracon Engineering and other local engineering firms. Reclamation's sponsorship of the contest is funded through its EEO/Diversity Program and student initiatives projects.

The funds provided by Reclamation are targeted to assist the committee in providing opportunities for economically disadvantaged students to participate in the contest by providing bridge kits to Title I schools and to promote science, technology, engineering, and mathematics.

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Reclamation is the largest wholesale water supplier and the second largest producer of hydroelectric power in the United States, with operations and facilities in the 17 Western States. Its facilities also provide substantial flood control, recreation, and fish and wildlife benefits. Visit our website at and follow us on Twitter @USBR.