Confused at a higher level

The view from a liberal arts college physics department (and deanery)

Teaching materials science with a twist

Posted by Melissa on March 24, 2011

At Carleton, spring break marks the transition from winter term to spring term, with all the usual hectic aspects of tying up the ends of one set of courses and getting ready for another. This winter I taught Physics 260 Materials Science; I’ve taught this course twice before, and enjoyed it both times. However, giving students an introduction to the vibrant and interdisciplinary field of materials science in 10 weeks, with only intro chem/intro physics as a prerequisite, is a challenge. Part of the challenge is that students come to the course with a wide variety of backgrounds, ranging from students who have only met the minimum prerequisites to senior chemistry or physics majors with extensive advanced coursework. Another challenge is choosing what to cover in ten weeks. Although the course was generally well received when I taught it in the past, a number of students mentioned that they felt the breadth of topics covered caused the course to feel a bit disjointed. Shortly after I last taught the course, in the winter of 2008, the Materials Research Society (MRS) published a special issue of the MRS Bulletin, “Harnessing Materials for Energy.” The special MRS Bulletin combined with the student comments gave me an idea for revamping the course, namely teaching materials science, but focusing on materials and how they can address energy and environmental challenges.

This year was my first attempt at teaching the course with a focus on energy/environmental issues. The course took the following shape. I spent the first three weeks introducing a few fundamental concepts for materials science: bonding and crystal structure, defects and diffusion, phase diagrams, and mechanical properties of materials. The remainder of the term was broken up into three majors units: materials for solar energy conversion, smart materials for energy efficiency,  and plastics and materials life cycle issues. The materials for solar energy conversion required an introduction to semiconductors and p-n junctions. In addition to exploring the basics of traditional solar cells, I also asked students to research dye-sensitized solar cells, quantum dot solar cells, and organic solar cells, and our discussion of solar energy conversion wasn’t limited to photovoltaics. We also discussed thermoelectrics and materials issues for concentrated solar power applications. The second unit, on smart materials, focused on shape memory alloys for smart grid applications and electrochromic materials for smart glass.*  I wasn’t able to have students explore as many of the other smart materials for energy efficient buildings as I had hoped, but I think with some redesign I can integrate other smart materials in the future. The final unit on plastics provided a basic introduction to polymers, traditional and biodegradable, as well as a discussion of materials lifecycle analysis.

While I really like the conceptual framework of the course, the implementation was a bit uneven this term, as is often the case after a significant course overhaul. I’ll certainly keep the energy and the environment focus when I teach materials science in the future. On the course evaluation, when I asked students what topics were their favorite/least favorite, there was a nearly uniform distribution of all the topics we covered so I likely will keep a similar array of topics next time. I need to improve the coordination between the readings, the in-class activities, and the assignments, but as I mentioned, that’s to be expected considering the new direction for the course.

Finding a text for this course was hard. We used Hummel’s Understanding Materials Science, Stevens’ Green Plastics, Ashby’s Materials and the Environment, and the April 2008 MRS Bulletin. These texts served their purpose although I’ll be keeping my eyes open for other options.  (In the virtual realm, the MRS has a very nice blog with recent research updates about materials for energy applications.)

The weekly course assignments contained a mix of writing, problem solving, and hands-on activities. By far, the hands-on activities were the most well-received. I had students build  and test their own dye-sensitized solar cells following the method laid out in Greg Smestad’s paper, “Education and solar conversion: Demonstrating electron transfer,” in Solar Energy Materials and Solar Cells 55, 157 (1998). Students also deposited and tested electrochromic films, an activity developed by the University of Wisconsin MRSEC.

All in all, I’m excited about the potential directions for the future development of this course, and I’m thankful that this year’s students were patient as I gave the course its first test-drive.

 

 

* I was particularly interested in electrochromic glass because a world leader in the production of electrochromic glass, SAGE Electrochromics, is located in a town about 15 minutes south of here. (We visited SAGE on a class field trip.)

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