Class Data Analysis

Data analysis will play a larger role in the new collaborative Organic Chemistry curriculum. I performed three experiments Fall 2007 where students entered their data before leaving the lab. The students were then directed to analyze the “class data” as part of their lab report. This is typically not done in traditional experiments for unknown reasons. One “class data” lab was our first lab using TLC to look at known compounds and compare them to a mixture of unknowns. On one hand, TLC Rf values are easily accessible. However, TLC is rather imprecise method, depending on the volume of sample spotted, the concentration of the sample, operator skill, time of development, etc… Asked to compare their data with class data, most students gave very qualitative responses: “My data was pretty good,” or “My data was about the same as everybody else’s.” This was not what I expected. Obviously, more deliberate treatment of data analysis is necessary. The second “class data” lab was a solubility lab where students were asked to determine whether a substance was insoluble, somewhat soluble, soluble, or very soluble in a given solvent. Each of these categories can be given a value and the numbers crunched from there. The third “class data” lab was a kinetics lab where they explored an SN1 substitution reaction. Students did better with the analysis part on this lab. However, the repeatability of the experiment itself is difficult due to the fact that it is very sensitive to the exact molarity of the reagents and the volume measurement techniques of the students. The comparative data gets pretty crazy sometimes due to systematic errors. My idea was to use this data as a starting point for Fall 2008 experiments. What can be learned from last year’s data? Are there ways to correct poor technique or poor reporting from last year? What is the next step in exploring this phenomenon? I’m thinking that more class time will be needed to prepare and plan the experiment this Fall, especially if students are going to participate in analyzing last year’s data and propose changes/modifications. The goal here is to make OChem laboratory more dynamic by moving forward instead of simply repeating last year’s experiment. Even if we repeat last year’s experiment, to a certain extent, there is a bigger goal that is being envisioned and students are participants in the process.

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