Well, you might done’ seen ‘bout everything, but have you ever seen a concrete Frisbee fly? If not, let us introduce you to Stephan Durham, assistant professor of civil engineering in the College of Engineering and Applied Science at the University of Colorado Denver.
Durham has been holding a concrete Frisbee competition since arriving at CU Denver in fall of 2005. The competition takes place each fall and spring semester in Durham’s Introduction to Structural Materials Course, a class that examines commonly used structural materials, their production, behavior and properties.
The goal to making a really good Frisbee, Durham explains is 1) make it lightweight and 2) durable. “The best method to making the Frisbee lightweight is by adding only cement, water and glass micro-beads,” he says. “The glass micro-beads are finer than tobacco smoke and really help in making the Frisbee lightweight.”
To make it durable, he says, “Add a wire mesh inside the concrete mold to help hold the concrete together once a crack develops.” The students have to throw the Frisbee three times during the competition and average the distance for their final score. “If a crack develops, you want to ensure it stays together.”
While some concrete Frisbee standards remain the same, students most certainly come up with original ideas and make ‘em fly. “I once had a student make an ‘aerobe’ [breathable disk] that just glided on the air – it went for over 100 feet,” he says. “The longest average that I have had over the years is approximately 125 feet ... this was the aerobe. Typically, semester to semester, it averages about 70-80 feet.”
Experiential education is important to maintain a student’s attention and focus, he says, noting a student's attention span is approximately one minute for his or her age, “My students can stay focused for about 20-30 minutes of a 1.5 hour lecture,” he says. “I have to include classroom activities, analogies, experiments, etc. throughout the class/semester to keep students focused and interested in the class.”
He’s also seen first-hand the best way students learn is to become interested in the subject and create a sense of enthusiasm about the subject matter. “That is what these experiments do... create enthusiasm,” he says. “Students are more likely to remember class lecture topics as a result of these activities.”
The concrete Frisbee competition is only one of the techniques Durham uses to engage his students. They’re also encouraged to take the American Concrete Institute (ACI) Concrete Field Testing Technician Certification. “On average, one to three students from each class obtain summer jobs, or advance in their job, as a direct result of being certified.”
Because of Durham’s work, the University of Colorado Denver, through the College of Engineering and Applied Science, has been chosen an ACI Outstanding University for 2010.