Regarding Formal lab reports must die,
Chem 13 News, December 2014/January 2015
Although I agree with Michael P. Jansen that a full-blown lab report might be a little too demanding at the high school level, I would like to address a number of issues that surfaced from his article.
- He pointed out that marking long reports "takes hours and saps a teacher's strength."I find that to be a weak counter-argument to requiring full lab reports. Marking is part of the job and we are home for about 165 days a year. Devoting a small part of that time to correcting should not be perceived as a downer.
Here are some pointers for making marking more efficient:
- Use a spreadsheet with algorithms to check student calculations.
- Give students a rubric for writing a good conclusion, which is essential in making sure the students have understood why the lab was done.
- Use questions for a guided analysis.
- As teachers, we have to remind ourselves that a lab and its report are far closer to doing real science than number-crunching on tests and assignments.
- We cannot use labs as MAD — mark-amplification devices. If the average lab grade for a class is higher than theory, it's a sign that we need to be developing better lab-associated skills.
Lauren Hill Academy, St. Laurent QC
Jansen makes an excellent argument which I wish to enlarge upon. The fundamental point that I want to make is that one should always think about what one is doing in the laboratory and avoid rigid rules which engender irrational fear. Most laboratories now have rules, mandating that disposable gloves, laboratory coats and goggles be worn at all times. A few years ago, false faith in disposable gloves led to the death of K. Wetterhahn at Dartmouth College, NH, from dimethylmercury — a liquid for which such gloves are no barrier.
Then there is the nearly universal ban on pipetting by mouth. Many Chem 13 News’ readers recall this technique — using the mouth to apply suction (as in a straw) to draw up a liquid into the pipette. It was much easier and faster than the use of rubber bulbs and vastly cheaper than mechanical devices. The ban on mouth pipetting came about because of the dangerous nature of certain materials. But there was no danger in pipetting water, phosphate buffer, dilute HCl and the like. The rigid rule puts these in the same category as bromine. This encourages students to put all
It is better to know about the substance’s effects on the hands, the eyes, or the mouth before doing anything with any substance in the laboratory. So, look up the properties of whatever substances that one is using. This way knowledge is gained. Blind obedience fosters ignorance. Safety should be considered on a case by case basis in order to avoid the surely evil unintended consequences that sweeping rules bring with them.
Ohio State University, Columbus OH