Innovative Education

From Hot Sauce to Solar Parking

Where do inventors learn to invent? That's a question Carnegie Mellon Professor Paul Sides and Lab Instructor Matt Cline were pondering when they dreamed up a new project for Chemical Engineering's Transport Laboratory.

Student teams were given $1000 and assigned the task of inventing a product or process based on momentum, heat or mass transfer. Each had to demonstrate a working prototype, create a poster that described the idea and technical underpinnings, and provide an assessment of how well the thing worked.

"When we announced the assignment, no groans greeted the news and several students visibly awakened," joked Sides. On a more serious note, he pointed out, "The experience of the first week surpassed all expectations. Each group came in with at least three ideas, some more than three. The atmosphere of the discussions was a mixture of seriousness and fun. The students were touchingly nervous about floating their ideas."

Some of the inventions the teams came up with included a solar parking lot; a better nozzle for hot sauce; more efficient hair driers; and a heated life vest.

As an example, consider the solar parking lot team. The concept was clear: tubes buried in asphalt and carrying a heat transfer fluid from the parking lot to a central heated water reservoir. But the questions arising from the implementation of this project were many.

The students had to decide: should we build a scale model of a whole parking lot with tiny tubes and a thin layer of asphalt-simulation material or should we build a representative section with a 12 cm layer of asphalt and real-scale tubes? Do we design first and build later or design and build at the same time? They had to pool their knowledge of engineering principles and figure out which would apply. They also learned that the amount of time available had an impact on their strategic decision making. All were lessons that would prepare them for the real world.

The hot sauce team purchased various bottles of the popular condiment and did "splat" testing of it shaken from the bottle. They found that the design of the nozzle or cap made all the difference. So they generated a new nozzle concept involving multiple openings arranged in a circular pattern. They then used a rapid prototyping machine to make it.

"The students were engaged in the lab and were even more present," Sides observed. "On the first day some groups were busily de-constructing commercial products to learn how they worked."

The instructors and teacher's assistant invoked engineering principles to clarify the logic behind the products when students asked questions. The teams pulled their work together during the final two weeks.

On the morning of the presentation session, Carnegie Mellon President Jared Cohon entered the lab and began visiting the posters. Sides cautioned him to step back a bit when the hot sauce nozzle was being demonstrated, which saved his suit. Local news media featured the event during their broadcasts.

"Students invented and realized their inventions with far more enthusiasm than for past assignments," Sides said. "The main lesson learned was that we have found a formula for engaging the students, and the project will certainly be repeated in the years to come."

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