Ominous popping sounds can be heard as the bridge's cross-bracing tears away from its superstructure.
Disaster is imminent. But Kimberly March shows no mercy. The safety-goggle-wearing seventh-grader relentlessly pours a stream of gravel from a coffee can into a 5-gallon bucket. An increasingly powerful dead weight, the bucket hangs from her toothpick bridge.
Torsion, compression, tension, sheer, bending - engineering terms for the forces at work - are all on display here. And that's exactly the point in this class of 14 students. So Kimberly and her bridge-building teammates, Grace Masters and Elizabeth Polido, soldier on - jaws clenched as their structure nears the breaking point.
Demolishing what took weeks to design and build isn't easy. But it is the logical next step in this unique technology-engineering education class at Hale Middle School in Stow, Mass.
Held in a onetime shop classroom in the bowels of this suburban school, the class is the first - but certainly not the last - of its kind. That's because in December, Massachusetts became the first state in the US to require engineering in K-12 curriculum.
It might seem strange to require engineering when K-12 students here and across the United States are struggling just to master basic math and science knowledge. But some see it as the perfect catalyst.
Ioannis Miaoulis is dean of the Tufts University School of Engineering in Medford, Mass., and a driving force behind the state initiative. Engineering, he says, melds math, science, social studies, language arts, and other subjects - making information understandable with engaging projects.
"Children spend a lot of time learning how volcanoes work, and little time learning about how a car works - yet they spend a much larger part of their time in car than they do around volcanoes," he says. "It's all about relevance."
Dr. Miaoulis has worked with schools in the area for more than a decade to get engineering into K-12. With the right curriculum and training, teachers in all grades can weave engineering into classwork and reap large benefits, he insists. "Even first-grade teachers can have children design an outdoor house for the pet bunny," he says.
Already, some are calling Massachusetts a national model for producing a new generation of students who will love math and science because they will see its practical applications. Gone will be the bad-old days (like right now) when US eighth- and 12th-graders score far below other industrialized nations on math and science tests.
Toward that end, the National Science Foundation (NSF) has provided Tufts with funding for the Miaoulis-inspired pilot project.
"What Massachusetts is doing is exciting because this type of development will lead students to have a real-world appreciation for math and science," says Norman Fortenberry, NSF's director of undergraduate education.
Right now, no K-12 engineering textbooks exist. Yet even though the curriculum is still under development, state officials felt compelled to take the leap.
The Massachusetts Board of Education voted 7 to 0 to work toward putting engineering in the state curriculum.
Amid hopes that the state will be a model, though, some question whether it might put teachers under a strain not unlike what Kimberly's bridge is enduring.
There is already an acute shortage of math and science teachers in the state and nationwide - let alone teachers with a knowledge of engineering.
"One of the big issues we have is about adding things to a curriculum that right now is way overcrowded," says George Nelson, who directs Project 2061, the American Association for the Advancement of Science's bid to improve US science education.
"In principle we're all for what Massachusetts is doing," Dr. Nelson says. "But ... you've got to make sure what you are taking out of the curriculum is not as important as what you're putting in. Otherwise it becomes just another unsupported mandate - and nothing happens."
One clue to how the problem might be solved lies with Brad George, a former shop teacher who over the past decade has morphed himself into a knowledgeable technology-engineering teacher.
With the help of Miaoulis and Tufts University graduate engineering students who assist in his class at Hale, he's shaped an engineering curriculum that centers on bridge building, 3-D drawing, robotic Legos, and rocketry.
"This used to be just a woodworking class," he says. "I still have some teachers and parents call it shop. But what we're doing here is way beyond that. We've integrated science, math, social studies - and made it real for these kids. And because of that, they learn it."
If built to full scale, Kimberly's graceful 25-centimeter-long structure would span 250 feet. She, Grace, and Elizabeth tested their design on a computer - predicting it would carry about 27 pounds.
Right now, though, it is carrying 40.
"Can anyone tell me the difference between dead load and live load?" Mr. George calls out. A boy shouts out an answer, his eyes glued on the breaking bridge.
Nearby is Lacey Prouty, a graduate student in engineering at Tufts. "Look at that torsion - does everyone see that?" she says, as the bridge begins to warp.
"It's about to go!" somebody yells. Sure enough, the bucket thuds to the floor, the road bed of the bridge torn from the supporting structure. George weighs the bucket: 43 pounds.
Despite supporting nearly two-thirds more weight than expected, there is an intense post-collapse analysis.
"We could have glued the road bed better," Kim says grimly. "What we had was a construction problem - not a design problem. It wasn't the torsion, because the arch held up okay."
The others agree. Perking up a bit, Grace adds that "cross-bracing could have been better."
Meanwhile, George turns to the rest of the class. Time for the next trial. Three boys hold out their sacrificial lamb.
(c) Copyright 2001. The Christian Science Publishing Society