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Willmar students' marble sorters could lead to engineering careers

Andrew Knutson, upper left, covers his eyes and Tyler Ahrendt, lower left, watches as Taylor Flegel, second left, and Angelina Gilland adjust their marble sorter during the Principles of Engineering class Dec. 21 at Willmar Senior High School.(Gary Miller/West Central Tribune)

WILLMAR -- There are easier ways to sort a dozen marbles.

But as a project in an introductory engineering class, designing and building a marble sorter isn't a bad thing to do.

Students in the Principles of Engineering class at Willmar Senior High were working on their marble sorters last week, before they left for the holiday break.

The students got a chance to show what they had learned about design and computer programming. Their problem-solving skills got a workout, too.

Using a building system called fischertechnik, Mike Kroeker's class of 28 students hunched together in small groups over their inventions.

They used the red, yellow and black plastic pieces, motors, photocells and circuit boards from the fischertechnik system, which Kroeker described as "Legos on steroids," to develop a way to sort the marbles.

The assignment was to have a hopper dump the marbles into the machine, where a photo cell would sense the difference between the clear and opaque marbles and drop them into separate trays. It must be run by computer.

There's a real-world application for such technology. Recycling centers could be more efficient if they could sort some raw materials by machine rather than by hand.

The inventions all had a different look. Some were long and low, other were tall and steep. A few were elaborate, while others were spare and utilitarian.

The hopper was proving to be a problem for some groups, either dumping too fast or plugging up. Many groups were using a water bottle with the bottom cut off.

One group had everything working, even their computer program, except they hadn't developed a hopper yet.

A chute to feed the marbles past the photo cell was another challenge. The marbles were feeding too fast in some cases, and the photo cell couldn't read more than one at a time.

The marble sorters are the major project of the class, which ends in mid-January. Kroeker said most of the teams would probably finish them up next week.

"We have about 99 percent efficiency when everybody's done," he said.

"Once they start to work with this stuff they realize some of them really do have the knack to do this thing," he said. "When they get to college, they're not afraid of it, because they've had success."

Pinciples of Engineering is an introductory class in the curriculum for Project Lead the Way, a national nonprofit organization working to increase the number of college students training in engineering and technology fields. Willmar offers the project's middle school and high school curriculum. High school students can earn college credits through some of the classes.

For students like James Liimatta, 16, a junior from Willmar, the class is a good fit.

"I like this kind of stuff," he said, as he and partner Cassie Yoakum, 16, worked on programming their sorter. "I enjoy building stuff and solving problems.:

Liimatta said he is considering a career in some area of engineering. Yoakum, a junior from Willmar, said she's not sure about that. "I need to look into it a little more," she said, but the class helped give her "a taste" of the field.

Ask the students in the class if they use knowledge from other classes they've taken, many will shrug, then suggest that they use a lot of science and some math.

Kroeker smiled at that. "There's math in just about everything we do," he said, but the students apparently don't notice that they're using it. They use their communications skills to document their daily progress on projects and to research and write about different areas of engineering.