From left, Baldwin City sixth-graders Caitlin Jacques, Jenna Flory and Riese Wismer prepare to test their Rube Goldberg machine Friday, Feb. 25, 2011, at the KU Engineering Expo.

Having meticulously assembled her bridge with all the care of a licensed engineer, Ainsley Agnew felt confident that her 3.75 pounds of uncooked pasta not only would traverse an assigned 30-inch-wide chasm, but also would hold up to the intense weight of personal expectations and intense competition.

Turns out only one thing could bring her down: 26 pounds of sand suspended from her glued-together span of wagon wheels, ziti and lasagna, during Friday’s Engineering Expo at Kansas University.

“It just collapsed,” she said with all the smiling innocence of a 10-year-old fifth-grader and aspiring chef — which, of course, she is. “A trapezoid is a pretty good shape to build with. You should build with a trapezoid or a triangle. That works better.”

Such lessons were stacking up Friday throughout the lobbies, hallways and classrooms of Eaton and Learned halls at Kansas University, as Ainsley and more than 1,300 elementary and secondary students participated in 11 competitions designed to spur interest in youngsters who just might end up engineering the next high-tech wireless phone, reliable car-safety system or ultra-efficient bridge structure.

That their pasta bridges snapped, or paper gliders missed their marks, or uncooked eggs dropped from the second floor cracked upon impact shouldn’t be seen as a problem, said Stuart Bell, dean of engineering.

Far from it.

“You really learn something when you fail, or when something doesn’t work right, you take it to heart,” he said. “They’re really learning some fundamentals. In engineering we say, ‘Always building products better, and better, and better.'”

Engineers learn, regroup and improve.

“We always make things better,” he said.

Ainsley, who will leave Cordley School for middle school next year, figures she could return to the Expo next year with a stronger design.

That, she said, “and lots of glue.”

The Expo continues from 9 a.m. to noon today, with tours and open houses at Eaton and Learned halls, northeast of 15th Street and Naismith Drive.