CHEM 601
INTRODUCTION TO LABORATORY INSTRUCTION
Ethics Cases

The following short ethics cases were written and published in the Journal of Chemical Education (1) by Paul M. Treichel from the Department of Chemistry at the University of Wisconsin-Madison and modified slightly by H. B. White.  Please read them and be prepared to discuss them in your group in class on Tuesday.  Did you engage in such activity as an undergraduate? How would or should you as a TA deal with each? What issues are involved? How might laboratories be changed to discourage such behavior?

Case 1: Trimming

Stephanie and Mike have been assigned to carry out an experiment confirming Boyle's Law. This involved measuring the volume of a gas sample at various pressures. In all, they collected 12 different sets of data. When they met after class to graph the data, however, they discovered that two measurements were way out of line. After deliberation, they decided that they must have made an inadvertent error in these measurements-perhaps in reading the meter stick or maybe just in writing it down in their notebook. Recopying their data onto a new sheet to turn in, they decided that the best course of action was to simply drop the two sets of "erroneous" data. Thus, their written lab report contained a neat table of the satisfactory data (10 sets of P-V data), with their graph showing all points lying on the line. They didn't mention omitting data in their report. As Stephanie said, “It doesn’t matter.  Like, we’re not going to disprove Boyle’s Law in a lab experiment.  After all, everyone knows what the answer’s supposed to be.”

Case 2: Forging

Later in the semester, Stephanie and Mike encountered the heat-of-reaction experiment. Here, they measured the rise in temperature in a coffee-cup calorimeter and calculated the heat of a reaction between an acid and a base. By this time, they had become pretty capable in lab. Preparing solutions took little time, and they were able to carry out the reaction between HCI and NaOH solutions in triplicate. Later that evening, they calculated the heat of the reaction. Two of their three determinations gave almost identical results, but the third was about 20% lower (about 10 kJ/mol). They thought briefly about dropping the third value and reporting only the two results. But they figured that three determinations would look better than two in their report. Plus, the TA might see from their data sheets that they had done the experiment a third time and would figure that they screwed up. So instead, they decided to simply change the data. They scratched out the final temperature in the errant data set and wrote in a value that was 20% higher. Using this number, they recalculated the value for AH, and it was close enough to the first two values to pass any reasonable inspection. Mike rationalized, “I’m interested in my grade. It might be wrong to adjust the data, but this isn’t research.  And besides, the TA will only grade us on the right answer.  He’s not interested in the data points we screwed up on and would have to explain away.”  Stephanie added, “Yeh, I once did a statistical analysis on my data and the TA took off for it.”

Case 3: Cooking

Stephanie and Mike passed CHEM 103 and continued on in 104. In their second experiment of the laboratory, they determined the kinetics of crystal violet oxidation by measuring the concentration of this colored compound at different times. To measure the concentration, however, they first had to prepare a calibration curve. This involved measuring the amount of light absorbed by solutions of known concentration and then preparing a graph of concentration vs. absorbance. The unknown concentrations would be determined from this graph, so the measurements on the standard solutions had to be reliable. Collection of this data was done by hand, point-by-point, and then entered into a spreadsheet program for analysis.

Two nights later, while Stephanie and Mike were in the Brown Lab Computer Lab working up their data, they ran into a problem. The first four measurements of absorbance plotted up nicely, giving a straight line, but the next four points were way off the line. Interestingly, all of these absorbances were too high, and the last four points traced out a straight line with a different slope. For awhile, Stephanie and Mike were puzzled as to which data to use, but then they remembered that midway through the experiment, they had broken the tube in which the absorbance measurements were made. (In fact, they had even made a note of this in their notebook.) Clearly the problem must have been with the new tube obtained from the stockroom. They decided that the logical way to deal with this problem was to impose a correction factor. So they decided to multiply each of the absorbance values obtained using the first tube by a factor of 1.04. Both sets of data were then used to plot a nice straight line. However, they decided not to mention their correction factor in their report because it was just too hard to explain. “And besides,” noted Stephanie, “lots of things go wrong with the old and unreliable equipment we use. We shouldn’t have to guess what went wrong. I’m sure if we had a computer to collect and analyze the data, it would be fine”

(1) Journal of Chemical Education,  76(10): 1327-1329 (1999).


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Created 26 September 2002, Last updated 22 September 2008 by Hal White [contact at halwhite at udel.edu]
Copyright 2008, Harold B. White, Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716