The pressure gauge topped 213 pounds before the sounds of cracking ripped through the Adrienne Korbel's classroom Monday afternoon.
The popsicle-stick bridge created by Casey Lakritz, a fourth grader at Wilson School in Petaluma, withstood 213.5 pounds before succumbing to the laws of physics.
Lakritz and five other students who take part in Wilson's after-school GATE -#8212; Gifted and Talented Education -#8212; class put their structures to the test Monday with a stress test machine on loan from Santa Rosa Junior College.
The sound of the bridge "failing" under pressure was drowned out only by the cheers of Lakritz's classmates who lifted the fourth grader in celebration.
"It was pretty cool," Lakritz said.
The segment on bridge-building on the Petaluma campus was taught by volunteer Jim Stauffer, father of a former Wilson student, who for three years has spent an afternoon a week using popsicle sticks to teach GATE students about structures and strengths.
"I'm still a big fan of science stuff and dream about science projects," he said.
Students studied various styles of truss bridges over the course of the program and were encouraged to mix and match various elements in their final structure, Korbel said.
The bridge building lesson brought a focus on physics, engineering and creative thinking, she said. She also encouraged students to share ideas and practice for their final presentation in which they had to describe for classmates and parents their strategies for success and how much they thought their bridge might hold.
"There are things like tension and compression, where they think the stress in going to be placed," she said. "It's trial and error -#8212; sometimes it sticks and sometimes it doesn't. They are kind of working things out, they take notes and make a plan."