During the past year various forms of the exercises and modules have been used in four different courses, three times in an introductory materials science course (total 330 students), in two third-year lecture courses (25 students each) and in one third-year laboratory course (20 students). This has given us limited opportunities to learn how to teach using spreadsheets, but the opportunities have been in three different types of courses. Experiences from two of these courses are described in the next section and advice I offer other instructors is given in the last section.
- Recent Experiences in an Introductory Materials Science Course
- Recent Experiences in an 3rd Year Materials Characterization Course
- Practical Advice
This course consists of four experiments which are performed every other week. The two-week cycle includes a discussion to prepare the students for the upcoming experiment, the laboratory session where the students do the experiment, and a formal report which is due the following week.
Spreadsheets are used in the preparation, execution and analysis/report phases of each experiment.
- Preparation - The preparation exercises ask the students to use spreadsheets to do a few preliminary calculations or to compile and plot data they will need during the experiment.
- Execution - Spreadsheets may be either central or accessory to the experiment.
- Analysis/Report - Recommendations are given for organizing and analyzing the results and for transferring this information to the laboratory report.
The four experiments and the role of spreadsheets in each phase are:
- Ionic Bonding - Modeling of ionic bonding in NaCl-type compounds using spreadsheets.
- Preparation - Calculate EMin for several compounds and compare them to reference values. Create a bar chart that illustrates the agreement.
- Execution - Extensive use of spreadsheets to calculate the E and F-r curves and analyze and plot the results. The students work from a model.
- Analysis/Report - Use spreadsheets to create tables and bar charts that show the results of the modeling.
- Mechanical Properties - tensile and hardness testing of several common alloys.
- Preparation - Look up selected mechanical properties of the alloys to be tested and illustrate them in a bar chart.
- Execution - Students had the option of, and instructor's support in, importing, plotting and analyzing the data. (This can be a time consuming project.)
- Analysis/Report - Students were given recommendations on how to compile their stress-strain curves and to add their data spreadsheet and plot done in the preparation exercise.
- Equilibrium Phase Diagram - constructing an equilibrium phase diagram for the Bi-Sn system from temperature transitions on cooling curves.
- Preparation - Lay out the data tables that will be needed when compiling the results from the experiment. Insert some numbers temporarily to test it, import data from the Internet and plot an equilibrium phase diagram.
- Execution - Compile data in the above spreadsheet and optionally import and plot the cooling curves.
- Analysis/Report - Recommendations were given on presenting the cooling curves in the report and on entering the data into the phase diagram.
- Recovery, Recrystallization and Grain Growth - hardness and tensile testing of half-hard 70/30 brass that had been annealed. Changes in the microstructure are also investigated.
- Preparation - Look up the properties for hardened and annealed 70/30 brass, plot them using a line chart.
- Execution - Compile the data using a spreadsheet. Optionally, import and plot the stress-strain curves.
- Analysis/Report - Plot all mechanical properties as a function of annealing temperature.
Spring quarter was the first time that we used the preparation and analysis assignments in this course and it seems to have a positive impact on the quality of the work the students did. (This conclusion is based on weekly conversations with the teaching assistants.) They gave the students a chance to do simple a warm-up spreadsheet exercises for each experiment and to receive some practical advice on how to prepare their reports. The students had 12 opportunities to use spreadsheets for both simple and ambitious exercises and hopefully have become more accustomed to using them. We'll know for sure when the results of the surveys are in and when they show up in my third-year laboratory courses.
This course dedicated four weeks to optical microscopy and interpretation of microstructures and four weeks to x-ray diffraction. Homework assignments for the x-ray diffraction experiments included spreadsheet exercises that asked the students calculate portions of the diffraction patterns they would see in their experiments. They were encouraged to use these spreadsheets in the analysis of their data by importing the experimental results and plotting them alongside the calculated curves. In another assignment they were asked to analyze the results of last year's crystallite size measurements. The students were given partially analyzed results (Scherrer and Warren-Averbach analyses) and asked to synthesize them, plot the results, etc. Later they could use this spreadsheet to perform the same analysis on their experimental results.
Most students did well on the homework assignments and many told me they found the exercises very helpful in being able to interpret the experimental results. Most of the work submitted, however, was difficult to read as little effort was made to organize and annotate the spreadsheets so that another person could understand how the calculations were performed. Also, few students took the suggestion to use the first spreadsheet to help analyze their data and prepare their report. Problems with the crystallite size experiment required that we change the procedure and use another method.
Next year the students will be given fairly strict submission guidelines for their spreadsheets, not unlike the submission guidelines they have for their laboratory reports. Also, using their spreadsheets in the preparation of the reports will be all but required, and exercises from a new module dealing with crystallite size measurements using x-ray diffraction will be incorporated into this experiment.
My collaborators and I have had a chance to use a number of the spreadsheet exercises in our courses. Based on these experiences I can offer the following suggestions for instructors who would be interested in incorporating spreadsheet assignments in their courses:
- Learn to use spreadsheets yourself and work the exercises yourself. There is a bit more to these assignments than the materials science and we have to be able to advise the students on spreadsheet issues.
- Do not rely on teaching assistants alone for help teaching with and grading these assignments. An intimate knowledge of how to solve the problems using spreadsheets, and the ability to anticipate their troubles, is essential.
- Start using spreadsheets early in the students' academic career. By the time they finish their second year they should have enough experience using the basic features of spreadsheets in solving engineering problems that they will not regard third-year assignments requiring spreadsheets as unusual.
- Use spreadsheets in your lectures. Demonstrate how handy and useful they can be. Bring your laptop an show graphs and tables of your data and calculations, and use them in an interactive mode. For example, use a vertical scroll bar to change the temperature in a diffusion or free-energy calculation so the students can see the graphs/numbers change.
- Offer concrete examples. Without a doubt the students need a model to work from. Their first assignments should be simple exercises for which they have a screen shot or printout of the spreadsheet hand to look at. This model can teach them how to layout their spreadsheet and structure their solution. A similar technique is often used in many introductory programming courses where the student's first assignment involves simply typing in the program in their text and getting it to work.
- Students will figure out a lot for themselves. If we can get them off to a good start they will find new and interesting ways to complete the assignments.
- Develop formal submission guidelines. If this is not done most of the work submitted will be barely readable, the spreadsheet equivalent of spaghetti code. Besides being unreadable, it indicates that their solution to the problem was not at all structured.
- All spreadsheet exercises should have clear materials science lessons or utility in a subsequent assignment. They should not be given just to get the students to use a spreadsheet.
- A brief report should be written or at least a question answered at the end of each spreadsheet exercise.
- I still don't know how to prevent students from "recycling" the previous year's spreadsheets.