By KELLI CATANA
PLATTSBURGH — Sixth-grade students at Stafford Middle School built miniature bridges — and then stressed the structures until they cracked.
The assignment was to design and build a balsa-wood bridge that would hold more than 30 pounds, span the gap and meet all specifications, constraints and limitations.
The students had to construct their bridges using wood glue and 60 feet of balsa wood. The structures could not exceed 10½ inches long by 5 inches high by 4 inches wide.
"Some kids have a hard time understanding math on a board," technology teacher Matt Tisdale said. "Here, we apply what they learn."
After the bridges were completed, the students tested their weight-bearing ability using buckets of sand. At least one of the small structures was able to hold 60 pounds.
"If you take something that's weak and change its shape, you can make it strong, using engineering principles," Tisdale said.
Students studied all types of bridges, including suspension, arch and draw bridges, and forces, like tension, torsion and compression, that act on them.
The project began by drafting plans on graph paper, then constructed truss-style bridges that had a triangular framework, which distributes weight evenly.
The students were amazed by how much weight the light structures could hold.
"The thing about sixth grade is that the kids still have lots of excitement," Tisdale said.
Anthony Girard, 11, and Anthony Portal, 12, nicknamed "Anthony Squared" by their teacher, constructed a bridge that held 60 pounds of sand suspended underneath before it cracked.
"I think our greatest challenge was constructing all four sides — putting them together," Portal said.
"I expected 35 to 40 pounds, not our actual 60."
