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

Last Wednesday was the second of two sessions I had with the students where the afternoon class attended in the morning. Unlike the experiment two weeks ago though, this one had only three setups instead of six.

I left it up to the students to decide which groups would merge temporarily, and the four groups from the morning class paired up, and so did the two groups from the afternoon class.

Fortunately the new lab manual in “Composition of Concurrent Forces” gives five different values for the three forces that are used for this experiment, so unlike what David did last February (and probably repeated last July) I gave a different set to each group so as not to compare solutions. The checking of their computations and percentage differences would take a bit longer for me, but I figure it was worth it.

The quiz I gave them was still enumeration like last time, but it wasn’t listing down of equipment anymore, but equations, particularly the ones we discussed in class last Monday that pertained to the component method. I also asked them for the relationship between the equilibrant force and the resultant force (180 degrees apart).

All in all they could have gotten 14 out of 10 for that quiz, but no one did. David’s brother got 10 though.

Like before I told them to get the equipment first so I could demonstrate the experiment. I showed them how to use the level to adjust the force table and minimize errors, especially if they don’t budge the table afterwards.

I also changed the addition in the manual again so that there are only two forces used for the first three parts (parallelogram method, polygon method and trigonometric method) and three forces (or four pulleys, pans and weights) used in the fourth method (component).

In retrospect, maybe the people who revised the manual were correct in assigning the three forces to the polygon method so that it would not look too similar to the parallelogram method. The component method would be okay with just two forces next time – that is, next term.

Afterwards I also asked one representative per group to come forward and get additional pointers on the graphical methods. Unfortunately, just like David noticed last time, there was something wrong with the trigonometric method, and that’s where they obtained their largest percentage difference. I was able to get the correct formula, but looking at the group reports they passed afterwards, some groups didn’t use it. Was this because I didn’t emphasize it to them at the start of the class just like the graphical methods, but instead relied on them to either ask me themselves or look at the whiteboard every once in a while?

This time, I did not anymore entertain the question of one of the students who kept asking before if it was correct that their percentages were so large. I told them their job in the group report was to compute, and it was up to those making the individual reports to try to explain the possible errors.

Speaking of individual reports, it was only then that I noticed that David’s brother had submitted papers for the first two experiments, when in fact the first individual report he is assigned is the third one. I told him he’d receive credit for the first two he submitted, and he did not have to pass the third one anymore. He insisted though.

This was also the meeting where they asked about a field trip. I tentatively scheduled a visit to the usual theme park for the third Saturday of November (the twentieth) but I told them that they had to assure a minimum number of participants (which is more than the number of students enrolled in that class) to be able to use the educational package discount. Otherwise, they would have to pay five hundred pesos per person.

I’ll end here for now. Tomorrow I’ll talk about the abbreviated Thursday and Friday classes. Class dismissed.