Radioactivity and the Limitations of Improperly Worded or Incomplete Labs
May 7, 2005
Analysis: Our results, as calculated, do not agree with any published information about cobalt-60. The activity rate reported on the source container is 1.0 μCi and our calculated activity is 9.28 x 10^(-19) Ci. This seems to be an unacceptable difference. The potential sources of this error are many. First, I found the conversion factors poorly explained. This may have led to an inaccurate equation for radioactivity. Second, I am not entirely certain that the factors given are accurate. Third, my seemingly incorrect derivation has led me to wonder if we recorded the correct readings from the radiation detector.
This situation is frustrating because I can't find the mistake here, whether it's mine or the lab's. My frustration is compounded by the fact that the lab doesn't provide an actual suggested form for the required derived equation. I don't think including a legitimate equation would detract from the lessons of the lab, as it would provide something against which to compare one's own derivation. I learn more from analyzing my mistakes than by attempting to follow vague, poorly-defined, inconsistent directions toward a suspicious equation that may produce numbers wholly unrelated to the experiment in question.
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It was toward the end of the semester. I really didn't have the time to cross check every little thing in this lab. I wish I had. But the instructor and I had realized early in the class that we saw eye-to-eye on several things, one of the more prominent being that we were both aghast at the incredibly poorly-written nature of the labs.
Full credit, by the way.
