Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: FRIDAY, February 22, 1991 TAG: 9102220467
SECTION: CURRENT PAGE: NRV1 EDITION: NEW RIVER VALLEY METRO
SOURCE: JUSTINE ELIAS CORRESPONDENT
DATELINE: BLACKSBURG LENGTH: Long
As part of the Academic Excellence Conference at Virginia Tech, high school students from across the state competed in math, science and engineering aptitude.
The teen-agers also were being wooed by the event's sponsor, Tech's College of Engineering, which held open houses on scholarships and academic programs.
Teams from Blacksburg High School and the Roanoke Governor's School won first place in their separate divisions in the Tests of Engineering Aptitude, Math and Science, one of three competitions held Thursday. Students from Christiansburg and Auburn high schools placed second and fourth in the division with Blacksburg.
But the highlight of the three-day event was Thursday's toothpick bridge contest.
Students used up to 800 round toothpicks and glue to build a bridge to span an 10-inch gap. Entries could be no taller than 4 inches, and all toothpicks had to be at least partly visible.
Instron Corp. of Reston, a company that makes materials-testing equipment, supplied a machine to measure how much weight each bridge could take before it failed.
Students constructed artistic arches, latticework transoms, miniature railroad bridges, jungle-gym-style spans, a punked-out spiked bridge - even a flat bridge that looked like a stockade fence dropped on its side.
Teen-age engineers stood by nervously as the machine bore down on their bridges. Judges were ready to note the first sign of cracking, splintering or collapse.
From the start, students were dead serious about the competition.
"Can't take more than 50 pounds," said one skeptic of his opponent's work. "OK, 60. Well . . . no way can it take triple digits."
And, as in any contest, controversy swirled around the apparent winner: a mighty triangle bridge that bore 1,000 pounds of pressure without breaking.
"That thing can't be legal," one disgruntled loser complained.
Instron's machine only measured up to 1,000 pounds, so when it hit its maximum, a wooden base used with the machine to hold the bridges broke.
In the end, Gary Mullins' boomerang-shaped bridge was disqualified.
The reason: The Lee High School senior from Jonesville had broken the rule requiring that all toothpicks be partly visible. By gluing together several layers of toothpicks, he had constructed something like plywood.
But Mullins' other innovation - attaching the base at an angle - was legal and effective. The sloped bases withstood pressure far better than buttresses or flat bases.
Three Blacksburg High School juniors, whose attempt at bridge building was a triangular shape, explained why certain designs work and others don't.
"The best way to hold weight between two blocks is a triangle," said Tommy Johnson.
As weight is lowered onto the toothpick bridge, the pressure pushes straight down. A triangular shape divides the weight, which pushes toward the edges - usually the first part of the bridge to give way.
"As pressure increases, it pushes out the sides," said James Lough.
Another trick is to make the toothpicks as strong as possible by breaking off the pointed ends - their weakest points.
Though many real bridges are built of arches, the arch itself is strong because it is all one piece. When students built arches out of toothpicks, the structure quickly gave way at the glued joints.
Next year, Johnson, Lough and partner Jim Murphy plan to use all 800 toothpicks.
"I'm impressed with the variety of their ideas," said emcee and chief bridge crusher Corey Zimmerman, district manager for Instron.
"I see some really good talent for creative thinking and creative engineering."
As one bridge began to splinter under only a few pounds of pressure, stray toothpicks burst into the air.
"This thing's shooting at me," said Zimmerman. "I give up."
Students spent between three and 20 hours on construction.
"I didn't do any research," said Jeremy Cline of Harrisonburg High School, whose bridge held 407 pounds. "I knew that a triangle shape would distribute the weight. I clipped the ends of the toothpicks so they would fit together better."
But Cline's project was eventually surpassed by the work of a Stafford High School student.
"I'll be back next year," said Cline, who already is planning his own radical design. "I may drill holes and dowel the ends of some of the toothpicks."
The rules don't say he can't.
In the separate competition Thursday based on engineering aptitude, math and science, Blacksburg and Christiansburg high schools placed first and second among the 16 state teams in their division. Auburn High School placed fourth.
The Blacksburg team will go on to the national-level competition in April. Its members are: Tommy Johnson, Remy Indebetouw, Anita Reddy, James Lough, Jim Murphy, Matt Stinchcomb, Jeremy Freeman and Max Schuetz. They were coached by teacher Dan Dunlap.
The Christiansburg team was: Meg Billingsley, Mike Nunley, Pam Arnold, Casey Cosgriff, Jennifer Wall, Danya Conn, Court Stewart, Lynn Shutters. Betti Kreye and Kurt Grosshans were the coaches.
Auburn High School's team was: Diane Williams, Amelia Sowers, David Smith, Phil Renfroe, Lisa Altizer, Lisa Higgs, Sharon Cox, and Rhonda Lytton. Its coaches were Bernadette Burroughs and Charles Jervis.
In the same competition, but a different division, Roanoke Governor's School won first place. Its team members are: Lindsay Cheng, Jennifer Clemmer, Matthew Lovell, David Schleupner, Seddon Thomas, James Turner, Carrie Woods and Andy Whitfield. Michael Brown was the coach. This team will also participate in the national-level competition.
by CNB