Maybe I shouldn't have started this blog now, not with everything that's been going on.

In my mechanics lab class last Wednesday morning I had the real morning students perform the experiment on Torque and Rotation, while the afternoon students (two groups of them) did Conservation of Mechanical Energy.

For this it was necessary for me to print out and cut up their quiz papers, so that there could be no collusion between the two classes as to the answers. Although it was a bit unfair to the afternoon class, their questions were more difficult than that of the morning class, since they do have the advantage of asking the earlier class what the questions are.

I was also thinking of just assigning them all the same experiment for that morning, but we did not have enough set ups (there were just five). And I didn’t want to merge the groups again like during the experiment on Composition of Concurrent Forces because it gave less people the chance to work (even then the epidemic on slacking was already showing its symptoms).

Immediately after the quiz I gave them the two major announcements for the next meeting.

First I told them that there would be no more Experiment Number 8. When students asked why, I said that the materials needed for the set-up did not arrive. What I didn’t tell them was that I did not find the materials that the students from two terms ago submitted up to snuff.

That meant that those who were assigned to pass the individual report on Conservation of Linear Momentum would now be tasked to write on the current experiment.

One of the “what if” students immediately piped up. He asked the scenario for those who are assigned both Experiments 7 and 8. I immediately cut him off and told him that I already checked and there were none such cases.

The next announcement that I had for them was that next meeting, since it has become freed up, would now be set for the practical exam.

I gave them the preliminaries of the practical, which is that the set up of each experiment would be placed on each of the tables, and that they would be asked to draw a number from a box. They had to know the experiments in sequence, what the set up looked like (they had to be able to distinguish between similar equipment used in different experiments) and they had to be able to give the procedure for the experiment – just the procedure.

Only if they are floundering with their answers will they be asked additional questions about the theory, the results, the sources of error and maybe even their recommendations on the experiment, to which most students’ batting average digs them even deeper in deductions* rather than bailing them out.

*I will also be telling them about the scoring system for this, which is that they will start out with ten points and receive one point for every correct statement and get one point subtracted for each incorrect assertion.

But back to last Wednesday’s experiment. This time (last true with Composition of Concurrent Forces) we used a pre-existing set up and not one submitted by the students from last April.

The first thing the students noticed was the different meter stick used, not the same wooden one that was always lent to them in previous experiments. Of course this was because a center of gravity as close to the fifty-centimeter point is crucial to the experiment, something that cannot be assured with meter sticks made of materials that could have unseen dense spots inside.

Another thing I agreed with the supply room custodian was that the weight pans used were not the previous ones taken with the hooks and loops of strings.

But I’ll have to cut my story short at this point. For now, class dismissed.