To passersby on the UA Mall on the sweltering afternoon of Oct. 20, the 500 students with tinfoil-covered reflectors might have been mistaken for idle sun-worshippers.
Along with the sun's rays, the freshmen engineering students were actually soaking up important lessons in math, physics, design and teamwork as they demonstrated 100 solar ovens they had built from scratch.
The annual spectacle called the Solar Oven Throw Down is a high-powered display of student ingenuity held every fall as part of the College of Engineering's required introductory course.
"I have never been on a team like this one," said Cassie Kimble of her team, the Sol-utions. "No slackers!"
The event follows six weeks of learning and applying core concepts in thermodynamics and systems modeling in class; poring over spreadsheets; designing, assembling and testing prototype ovens; and returning to the drawing board to construct even better ovens.
Turning Up the Heat
Teams of four to six students developed mathematical models to guide design, construction and performance prediction of their ovens. The goal was not to build an oven that would reach the highest temperature; rather it was to accurately predict the highest temperature the oven would reach -- the "performance index" -- on the day of the contest.
Teams also vied to predict average oven temperature and build the most inexpensive oven.
Students could use only commonly available materials like cardboard, aluminum foil, construction paper, duct tape, Mylar film and newspaper. Oven chambers had to be at least 5 centimeters in height and have a volume of 1 liter, and reflector surfaces had to be flat.
Still, teams made the ovens and presentations their own. Some reflectors had four sides, others eight; some chambers were covered in black tape, others in colorful decorations. One team wore chef's hats.
Under blue skies with temperatures topping 90 degrees, the teams fine-tuned their ovens up to the very last minute -- 4:05 p.m.
"The hardest part has been keeping our oven well insulated," said Isaiah Engle, a member of the Look on the Bright Side team. "We added a lot more newspaper to our second prototype -- and we're still having to add on all the duct tape we've got left."
While the ovens had to reach at least 100 degrees Celsius, a few doubled that. One sizzled at 241 degrees Celsius -- 465 degrees Fahrenheit.
A College Tradition
Freshmen in the College of Engineering have been making solar ovens in the introductory course for many years, said Brian Cunningham, course coordinator and lead instructor, but only for the past seven years have class sections come together to compete at the Solar Oven Throw Down.
Student/Faculty Interaction Grants from the UA Office of Student Affairs and Enrollment Management help support the event, which was sponsored by the international technology company W.L. Gore & Associates for the fifth consecutive year.
Six Gore engineers -- four of them UA Engineering alumni -- attended the Solar Oven Thrown Down to evaluate the students' teamwork and select the winner of the company's "All-In the-Same-Boat" award.
This year there were two winning teams.
"We have never had a tie for the award before, but we felt that both teams really captured the spirit of our award," said Rae Gargione, who earned her bachelor's degree in industrial engineering from the UA in 2012.
"The Mahi Tram team highlighted the different roles and jobs each member took on, based on their skills. And Tres Amigas impressed us in describing how, after a fourth member had to drop out of the class, the three remaining teammates took on additional responsibilities to ensure the team's success."
Engineering for Good
Solar ovens improve and save lives in developing countries, where power sources and safe drinking water supplies are limited. The Solar Oven Throw Down demonstrates the good engineers can do.
Some freshmen learned how to make water pasteurization indicators and put the devices inside their ovens, instead of biscuit dough. The devices contain small tubes of soy-based wax that melts when water is safe to drink -- at a temperature well below its boiling point but sufficient to kill waterborne disease-causing organisms.
Winners of the Gore All-in-the-Same-Boat Award
Hameeda Muneer Al Saif, Amy Nicole Littlefield, Nicole Renae Wigtil
Instructor: Steve Poe
Samuel Jamison Armstrong, Sohil Gopal, Matthew Bryan Heger, Travis Jay Lee
Instructor: Brian Cunningham
Winning Section for Highest Average Performance Index
Instructor: Cac Dao
Average Performance Index: 37.58 degrees Celsius