Newswise — Associate Professor of Physics Ed Pogozelski and his student bridge-building competition have come a long way since the spaghetti year of ’97. That’s when he used food as the construction material of choice after learning—just two weeks ahead of time—that the annual physics department event was among his responsibilities as a new adjunct.
Demonstrating a basic law of physics, Pogozelski (Pogo to students and colleagues) became an object in motion—and didn’t rest until the contest was over. It was a brief pause only, as he’s directed the event ever since with the exception of 1999, when he taught at Rochester Institute of Technology.
The assignment is part of Pogozelski’s course, Applied Mechanics PHYS 313, which blends theory with hands-on work “to help students analyze structural engineering problems (beams, cables and trusses) and use the concepts of stress and strain in structural members experiencing tension, compression, shear, bending, and twisting to evaluate the possibility of their failure.”
“We used spaghetti my first year, but only in the interest of time,” Pogozelski explained. “It’s not the best construction material because Elmer’s glue ‘cooks’ the spaghetti which makes it difficult to use.”
His predecessor used bamboo, and for a couple of years, Pogozelski used popsicle sticks but those, too, were not ideal.
“The designs became boring due to the consistency of size, even after increasing the length requirements for the bridges,” he said. “There are only so many triangles you can make with the sticks.”
He switched to balsa wood starting in 2000, providing different sizes and dimensions to allow students greater design latitude.
The physics department supplies all materials, except glue, with no substitutions allowed. Students may cut the balsa into various lengths but cannot deviate from strict design and construction requirements. For example, the bridge span must be at least 120 but no more than 132cm, and its mass may not exceed 265g.
Students spend hours designing and building their bridge only to see it destroyed in a matter of minutes. In the early years, Pogozelski stacked weights to bring down the bridges. Today, he uses “Destruct-o-con,” a device he created with students as part of their directed study that allows him to control force over time.
Employing gears, springs and pulleys, “Destruct-o-con” gradually applies force to break the bridge, scattering pieces of balsa wood everywhere but not before capturing data through its sensors. Pogozelski and his students analyze the data to determine the weight supported by each bridge.
“I want each student’s bridge to last about three minutes,” said Pogozelski, who revealed that successful construction constitutes 25 percent design and 75 percent craftsmanship. “The winners usually go five to six.”
Yet, students don’t mind watching their engineering creations destroyed before their eyes. Seniors and project partners Anthony Tantillo and Danny Finn started working on their bridge a month ago, investing 10 to 14 hours in the effort that counts as 10 percent of their grade.
“There’s more application in this class versus others that are more theory," said Tantillo, who plans to attend graduate study and pursue a career in 3D printing. “It’s going to be fun to watch.”
“It’s kind of the first class I’ve taken that offers real-life application,” echoed Finn, who plans to attend graduate school and pursue a career in automotive engineering. “You think going into it you have all the knowledge but once involved, you realize there’s a lot of guessing, too.”
This year, eight bridges were submitted by 15 students but (SPOILER ALERT) none will survive Destruct-o-con. While the first- and second-place winners will walk away with bragging rights and a small cash prize, all students will gain something more valuable.
“Pogo flushes out of his students all feelings of embarrassment for making mistakes … but at the same time, drills the importance of accurately arriving at the correct solution,” said Holly DeSmitt ’16, who took first place last year with Jarrett Vosburg ’16. “This is a delicate balance, but critical in the field of science and engineering.”
“Many of the skills I used in preparation for the contest are valuable in the workforce, including time management, planning, teamwork, communication, decision-making and follow-through,” added DeSmitt, who majored in applied physics with a minor in math. She’s employed by Harris Corporation as a space environments engineer, helping to ensure the survivability of spacecraft that must withstand harsh radiation environments in orbit.
Pogozelski became a full time member of the physics faculty in fall 1999. He earned his bachelor's and doctorate degrees in mechanical engineering at Carnegie Mellon University and The Johns Hopkins University, respectively. He previously taught at Rochester Institute of Technology and Houghton College, and before that, was employed at Westinghouse Electric Corporation where he worked on the design and manufacture of U.S. Navy nuclear refueling equipment.