What is the purpose of lab?

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In thinking about my lab practical exam, there are two major components:
1. Can the students analyze data appropriately and draw conclusions?
2. Can the students perform the hands on tasks correctly?

Which brought a colleague and me to the discussion...is the purpose of lab to teach students hands on skills? If yes, then we should test on ability to set up certain apparatus, use pieces of equipment etc. However, many students will never be organic chemists, microbiologists, (insert favorite lab skills) and the instrumentation they use professionally will likely be different from that used in the lab.

Or is lab to help students understand the concepts learned in class by 'making them real'? Then our lab practicals should be all over the concepts and the data analysis and forgo the pipetting and skill components.

Both? help.

Yes, the purpose of a "lab science" class is to use *stuff* to help students learn, and give them practical experience using the *stuff*. They gather data, run experiments, and use critical thinking to analyze their data. Even if you're just looking at microscope slides or picking leaves off of trees, the methodology is still there and is a critical component to the scientific process.

Operating the lab equipment is a prerequisite skill for everything else done in the lab. So it is perfectly valid to have equipment operation as practical exam assessment in a laboratory science course.

I think it really depends on the course.  In general Chemistry here, (1) is making the chemistry 'real' is more important than actual use.  In gen chem 1, almost every experiment is a new technique and I expect a certain amount of screwups.... but they should be able to explain it.   Although I do include some grading for completely bogus results  (your density of water is 2 g/mL.... Really?)  and I focus heavily on understanding correct measurements, I'm more focused on showing them what chemistry looks like, and how to interpret their data.

This does change  when we move to Organic.  In this course we have a set of techniques that they use over, and over again.  The labs generally get more complicated and finicky as we progress (gearing them up for 3rd year labs).  While I still consider interpretation important, technique is now a major portion of the grade.  If they can't use those techniques, they can't possibly pass.

I had two types of undergraduate labs as a student:

Type 1 involved experiments.  Here the main goal was to ingrain hypothesis-testing into our heads by repeating it over and over.  We were given a question, talked through the hypotheses, figured out (with the TA's help) how to test the hypotheses, and had to write lab reports at the end detailing the process and justifying the conclusions.  Each lab also reinforced a lecture topic.

Type 2 involved learning to identify things: how to tell different genera and species of similar organisms apart, for instance.  The goal here was to acquire get non-classroom knowledge and apply it.

I think of the purpose of lab as "To model how scientists do things." Students gain practice at doing things like scientists.

Grand scale, that is modeling how we think, set up experiments, test hypotheses, interpret data.

Small scale, that is modeling how to run the analysis, how not to contaminate your sample, how to push the button.

So I say the answer to the original question is YES. Both aspects are fair game.


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