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Riverdale High School dominated the Oregon Regional Model Bridge Contest and will send two students to compete in Baltimore on April 6

REVIEW PHOTO: CLAIRE HOLLEY - A bridge is tested using the Vernier structures and materials tester used by Riverdale bridge builders.Riverdale High School students claimed all of the top 20 positions for the seventh year in a row at the Oregon Regional Model Bridge Contest. The competition, held Feb. 23 at Oregon State University, determines who can design, construct and test the most efficient bridge within the specifications.

Riverdale has a long history of success in building bridges, according to physics teacher Mark Wechter, who has taught at the school for over 20 years.

"We've taken the top two positions in the state for the last fourteen years," he says.

This year, the top two winners were junior Jack Bride (with an efficiency of 4,166 – so far the highest efficiency posted nationwide) and sophomore Alden Tinkham (with an efficiency of 4,065). The two will move on to the international competition in Baltimore, Maryland on April 6.

Bridge building teaches fundamental physics skills, involves hands-on learning, and gives students insight into the life of an engineer. During the regional competition, they also get the opportunity to interact with OSU engineering students, professors, and professional engineers.

"For my son Jack, who wants to be an engineer and is a hands-on learner, this opportunity was invaluable to him," says Kristin Bride.

Wechter says he built his first model bridge in his dad's psychics class, and was hooked ever since. When he began teaching at Riverdale, he introduced the program, and it took off from there.REVIEW PHOTO: CLAIRE HOLLEY - Riverdale physics and engineering teacher Mark Wechter shows how to use the Vernier structures and materials tester, invented by former LOHS teacher Tom Smith.

Now, Wechter says he gets calls from teachers across the state asking for bridge building advice. According to Wechter, simplicity is key.

"A simple, elegant design that addresses the rules for that particular year will outperform an overly complex design every time," he says.

The specifications for the bridges change every year to keep the competition challenging. This year, one side of the bridge had to be placed one centimeter higher than the other during testing, creating a small incline.

The bridges are tested using a machine invented by former Lake Oswego High School physics and engineering teacher Tom Smith, who now works for Vernier Software and Technology. The "structures and materials tester" allows students add weight, or strain, to the bridge in order to identify weak points. The same machine is used to test the bridges during competition.

According to Wechter, the goal is to create the lightest and strongest bridge.

"This year, our winning bridge weighed one third of an ounce and could hold 110 pounds," he says. "It has to do with the density of the wood. Students meticulously weigh and separate each little piece that goes into the bridge."

Wechter says his class spends a lot of time discussing the rules governing the strength of each bridge component, identifying the type and magnitude of force each piece will undergo, and the impact of different thicknesses, lengths and densities of wood. They use diagrams of Portland bridges as well as theoretical bridges for practicing their skills.

While Wechter helps students with their bridges, his assistance is limited by the rules of the competition.

"They are allowed to ask as many questions as they like about design elements and rules, but each student in good faith needs to be able to sign a sworn statement certifying they designed and constructed their own bridge," he says. "This is also why my answer to their questions is often, 'It's your bridge,' by which I mean they need to make their own decisions about their bridge, and they need to have solid logic supporting their decisions."

In order to create a great bridge, Wechter says, students must be prepared to fail again and again.

"I always tell them, it's going to be uncomfortable, but we're going to set you up for success," he says. "They have to be willing to fail. It's a part of the process."

For more information about the Oregon Regional Model Bridge Contest, visit this website.

Contact Lake Oswego Review reporter Claire Holley at 503-479-2381 or This email address is being protected from spambots. You need JavaScript enabled to view it..

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