1 May 2016

# Teaching a review session with “blue solids”.

Submitted by Adam R. Johnson, Harvey Mudd College

I’ve heard great things over the years about the “Blue Solids” learning object. Things like “it’s a great ‘introductory’ solid state literature discussion,” or how the students really like the paper because it is easy to read. Towards the end of the semester when I’m trying new things in my class (i.e., not my home-field of organometallics), I get a little desperate and want to incorporate something I know that works. This year, I had a lot of student interest in materials so I ended with solids and semiconductors, and decided to use my last full day of teaching this semester as an in-class literature discussion of the blue solids paper.

Well, I can say that the LO is, in fact, quite good, but perhaps not in the way that was initially intended. Since it was the second to last day of the term, the students were getting a little antsy about the final and wanted to see some review material. I gave them the blue solids reading on Monday, and we discussed it on Wednesday. I had never read the paper but used the literature discussion questions prepared by Barb and Maggie (the short version of 8 questions). When I finally sat down to read the paper, I was taken aback at two things. First, that the paper really was quite easy to read and understand as a non-expert, and second, that the paper encapsulated a number of learning goals I had laid out at the beginning of the semester. Here are the topics in the paper that I was able to address in class as the first part of my review of the material:

Ionic radii: the discussion questions ask the students to consider radii and which ions fit in which spaces

Counting ions in a unit cell: I often struggle with what to teach in the solids unit, but being able to determine the stoichiometry from the unit cell is one thing I always cover

Basic coordination geometry: the paper describes trigonal bipyramidal manganese centers, and compares them to octahedral geometries, and uses the terms basal and equatorial

Crystal field theory: the paper gives a CFT pattern for the trigonal bipyramid geometry

Magnetism: while not specifically in the paper but in the discussion questions, the difference in magnetic properties between high spin and low spin Mn2+ can be discussed

UV-Vis spectroscopy: The paper describes the d-d transition responsible for the color, and the energy level spacing makes sense from the crystal data (compression along the z-axis changes the CFT pattern)

In addition to the science, students are given an opportunity to read the different parts of a paper (figures, tables, text) and understand what goes in the supporting information. We also could have discussed references (for example, are wikipedia articles acceptable sources for references 2-5?) and citation style.

Students had a number of questions about the article, and the scientific process. For example, did the scientists sit down one day and say to themselves “lets make a blue solid?” probably not. Possibly more likely, the graduate student accidentally added some Mn2+ to an experiment and they stumbled onto the blue color. In any case, how science is conducted is different from how science is presented. Finally, the paper gave an example of a real solid state synthesis technique that we were able to relate to their experiences in the organic and inorganic lab sequence: “heat and beat, followed by recrystallization from a PbF2 flux” is similar to “reflux, followed by recrystallization from hexane/ether.”

This year I was teaching an overload, and I didn’t get to use as many literature discussion LOs as I had originally intended. Using lit discussions is a great way to bring current research into the classroom, but never think that it is an easier way to teach. It absolutely is not. One thing I learned about my teaching and my students (and probably your students too) is that they really would prefer to be lectured to. Self-actualization in the classroom is hard for them, but I firmly believe that it is the better way to teach, and there is much literature to support this view (references below). I hope the students learned this material better because of the paper, even if it was just review for the final exam.

References:

Reaching Students. What Research Says about Effective Instruction in Undergraduate Science and Engineering,” by Nancy Kober, National Research Council.

Active Learning Beats Lectures,” by Celia Henry Arnaud, C&E News, June 2, 2014.

Scott Freeman, Sarah L. Eddy, Miles McDonough, Michelle K. Smith, Nnadozie Okoroafor, Hannah Jordt, and Mary Pat Wenderoth, PNAS, 2014, 111 (23) 8410-8415,

A Nobel Laureate's Education Plea: Revolutionize Teaching,” NPR, April 14, 2016,