Tuesday, May 15, 2007

Long time, no post.

Wow, it has been a while since I posted. Once the semester ended, I got distracted with graduations and family matters. It was all good, but not conducive for thoughtful posting.

In lieu of a thoughtful post I am going to post about lab reports. My last post elicited a significant amount of discussion on lab reports (hey, for this blog, 9 comments is a significant amount of discussion).

Sorry I'm a little slow getting to this, but better late than never.

I teach three classes (at least last semester). General Chemistry, Organic Chemistry and General Biochemistry. I have no TAs. I am the lab instructor and stockroom person. In addition to numerous faculty committees and divisional responsibilities, I have very little free time. Such is the nature of teaching at a small, private liberal arts college.

As a result, I am regularly swamped with grading.

In my General Chemistry class, every lab requires a brief lab report. I use CER labs, not because I think they are so great, but because they make things easier for me. I really wish I could do something different, but not until I have less on my plate.

In my Organic class, I do not require lab reports. In lieu of lab reports, my students must keep a well organized lab notebook. They are graded in a number of different ways. First, I give notebook quizzes. Every month or so, they have to complete a quiz using only their lab notebook. This is all designed to make sure they are recording things they should be (i.e. reactions, melting points, observations etc...) A second way is to require them (usually at the end of a semester) to repeat an experiment using only their lab notebook. The ones who keep good notebooks usually do quite well. They are also graded on technique and safety. I never grade on yield

In my Biochemistry lab, I require (usually) two formal written lab reports during the semester. The report is on a lab or sequence of labs they did during the semester.

There is great value in learning how to write a lab report, but I don't have enough time to fully grade them. As a result, I let that slide a bit.


Ψ*Ψ said...

See, those sound like very reasonable requirements. My gen chem lab required short lab reports (maybe 2 pages), about one per week, and so did my organic lab class. This was not bad.
I like the idea of writing one or two formal reports per semester on a series of experiments. I'm reminded of my crystallography class last semester, which was mostly spent in the lab. We had many in-class exercises, but only one formal report at the end (which was a CIF file for a crystal structure we had solved from data we had collected individually). That was an excellent class, though, and such practical evaluations seem to be more the exception than the rule. It seems like that kind of organization requires considerable forethought on the part of the instructor, which is generally not going to happen at a large research university (once developed, the curriculum seems to stagnate for lab classes).
Decent notebooking is something I WISH I'd had to do for a class, rather than learning the hard way (after looking back through old notes to repeat a procedure and then realizing I left out a crucial detail). That's much more practical than any sort of formal paper, I think. Probably it's best that you don't grade on yield. This only inspires students to falsify results if they are intensely concerned about grading (which I never was, but most of the students in the organic labs here are looking to go to med school).

Chemgeek said...

I learned to keep a good lab notebook the hard way too. There were too many times that I failed to reproduce an experiment because I forgot to include one or two pieces of apparently crucial information.

For my students, it is usually work up conditions and purification conditions.

I don't grade on yield because, so much can go wrong. I prefer my students learn from their mistakes and not be penalized (unless they don't learn from their mistakes).

The only time they are graded on yield is at the end of the school year. I challenge my students to an aspirin synthesis. We do the lab side-by-side and the number of points they get is based on purity (as judged by FeCl3 test) and comparison to my yield.

Since I am the "expert" my yield is the benchmark. Plus, with the 20-30 year old bottle of acetic anhydride we use, 75% yield is pretty good. This year, no student surpassed my impressive 73% yield.

Liberal Arts Chemist said...

Yeah, that sounds like the same kind of load that I have. You made different decisions on evaluation which I respect. We exist in the shadow of two majour universities where our students often transfer so if I want my courses to transfer, the big universities have to recognize the course I teach. Thus, I have a lot of marking.

Chemgeek said...

The bottom line is that assigning a grade to a student when the semester is over is much, much more difficult than most students realize. Everything that goes into determining the grade is much more involved than I ever anticipated.

Elderchemgeek said...

...assigning a grade to a student when the semester is over is much, much more difficult than most students realize. Everything that goes into determining the grade is much more involved than I ever anticipated.

Hmm, I always wondered how I passed. Cynthia must have used an alternative grading scheme. Cool insights, thanks bro!

Matt Jenks said...

I really like the way you grade the organic lab notebook. I wish my prof had been as strict, but then, she was a biochemist teaching organic chemistry, so we were light on the reaction side, anyway. At the end of the semester, I cobbled together a crap-tacular (especially when compared to how I keep my notebook now) notebook and still got good credit for the course. If I were the teacher, I'd have busted my balls over the garbage I tried to hand in.

My biggest lab report was when I had to do an "independent" research project in my biochemistry course. It actually turned out to be more like a very, VERY light journal article. This was also the closest I came to writing a formal lab report until I had to write up the seven reactions I tried my first semester as a grad student in the lab.

Also, kudos on not grading on yields. Synthesis isn't as easy as we'd like to pretend it is...especially if you're following the prep of a Sames paper. *whistles innocently*

Ψ*Ψ said...

Or anything from Tet Lett, for that matter. AARGH! (I have one going now, and that's where the only thing published on it is)

shamim khan said...

The lab report should include all important information related to the experiment in a concise ... This must be completed before class or you will not be allowed to ... You should print this form from my web page to turn in with each lab report do my lab report