What's a hydrogel? How do chemical engineers design mixers for viscous fluids such as chocolate? These and other questions were answered at the AIChE-sponsored booth at the recent 3rd USA Science and Engineering Festival (USASEF) in Washington, D.C.
The event, labeled "the largest celebration of science and engineering in the U.S.," filled the Walter E. Washington Convention Center in Washington, D.C., with over 750 exhibits, 150 performances and lectures, and a STEM career pavilion. Held from April 25th through April 27th, it attracted over 350,000 visitors, including more than 1,000 who stopped by the AIChE booth. While the festival seeks to attract people of all ages, the chief target is "middle and high school kids and their families," according to Festival founder, Larry Bock, a high-tech entrepreneur.
The AIChE exhibit was staffed by volunteers from Air Products, Auburn University, Dow Chemical, Hershey Company, and Philadelphia Mixing Solutions. The theme was "Mixing It Up with Polymers," as various aspects of how chemical engineers make and process polymers were highlighted.
In one demonstration, students saw how the properties of a fluid (namely, its viscosity) influenced the thoroughness of mixing in a stirred tank, with colored beads used to show the mixing patterns. By changing the impeller design, the students could also see how chemical engineers adapt the mixing system to account for the changing fluid properties, and ensure thorough and complete mixing.
The booth also included an experiment in which students could combine a polymer powder (PEGDA, or polyethylene glycol diacrylate) with a photoinitiator, to make a cross-linked hydrogel material, capable of holding many times its own weight of water. Both traditional (e.g., disposable diapers) and cutting-edge (e.g., artificial body tissues) applications of the technology were described, and students were able to take a small sample of hydrogel home with them for further experimentation.
Given that the target audience was school-age kids, a generous donation from Hershey candy provided an effective means of attracting people to our booth and starting conversations. (As well as serving to keep the volunteers energized!) In addition, our booth was selected as an "Engineering Passport" stop, in an activity sponsored by Raytheon and DiscoverE; visitors to our booth received a passport stamp, and were able to collect a prize after accumulating five such stamps.
This year's Festival was the first at which AIChE participated, and, based on the enthusiastic response we experienced, we hope to be back for the next Festival in 2016.