An early favorite was a contraption that looked like a hybrid of an accordion and a croupier's rake, with a G.I. Joe action figure mounted on top for good measure.
Other smart money was on a paddle wheel model dubbed The Blender.
And some people liked The Criminal, a flat-bed gizmo complete with a yellow net that shot out unexpectedly.
But in the end, victory went to a sleek, black, wedge-shaped entry that made up for its lack of crowd appeal with shrewd counterattacks.
It may not be what people send their children to Caltech for, but assistant Professor Erik Antonsson insists that last Thursday's Ping-Pong ball collecting competition--formally known as the Fifth Annual Caltech Engineering Design Contest--was educational.
"Most of engineering education is classroom, paper problems, questions, and homework sets. They rarely in school get a chance to learn how that applies to the real world," Antonsson said. "This class is one chance for them to see how all the other science and engineering they learned really does work in the real world and to learn how to put it all together in doing engineering design."
About 350 screaming, sometimes booing, spectators turned out at Baxter Lecture Hall on the Pasadena campus to watch the rivals in action.
The competitors, 20 students enrolled in Antonsson's class, had received identical sets of materials to build their Ping-Pong ball collecting machines. The assignment started 10 weeks ago, when each received "a bag of junk," which included assorted pieces of plexiglass, Venetian blinds, paper clips, rubber bands, two motors, and, of course, four tongue depressors.
Some students spent as many as 250 hours building their machines. And Thursday was their moment of truth.
Competitors squared off two-by-two in the early rounds of the contest. The rounds were played on a table with a wavy, slick Masonite surface. In the center of the table, 300 Ping-Pong balls sat in a trough. Then the contestants plunged in. They had 30 seconds to gather as many Ping-Pong balls as they could. In the heat of battle, the balls churned furiously.
Rules of the contest allowed competitors' devices to interfere with those of their opponent. They also were permitted to swipe Ping-Pong balls the other player had gathered.
In the championship round, Charles Cook's entry upended and disabled The Blender, created by Sandor Nagy, leading the way to victory for Cook.
"I started just planning to make a wedge so that I could go through the Ping-Pong balls so I wouldn't push them to the other side," said Cook, 20, a mechanical engineering major in his junior year. "But I realized that if I could get underneath some of the people with the high centers of mass, I could tip them over, and then once they are disabled, I could go and collect all the balls I wanted."