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

Friday was the last group to perform the experiment on Atwood’s Machine, also known as the verification of Newton’s Second Law of Motion.

We had started out using pulleys on the horizontal attachments to the iron stands, but the pulleys were too small and the weight pans were too big that while the heavier one went down and the lighter mass went up, the pans would hit each other.

An alternative set-up was using two pulleys instead of one, while yet another one utilized the force table with two pulleys set 180 degrees apart. Since the force table is low in the first place, it had to be placed on a stool and the weights given the floor as their starting position.

Groups who broke their strings and had to retie them were told not to be concerned with the knots hindering the speed of the descent (and ascent) because the contact points of the pulley and the string were not supposed to be frictionless; the pulley around its axis was.

And even though it was obvious from the first group last Wednesday that the weights should not have been given just five or even ten gram differences because it was not heavy enough to overcome the friction still present in the pulleys, I couldn’t change them for the later classes because it made David’s job of checking the manuals easier.

Another problem is that now, for the question as to what is the greatest source of error in the experiment, instead of saying “the subjectivity of the experimenter starting and stopping the timer”, just like with the experiment on uniform acceleration, they students are going to say, “the friction.”

One group, by the way, that I helped last meeting (two weeks ago) with their graphs on projectile motion, got a zero in the manual. And, naturally, they blamed me. I told them that I remembered their graph as being parabolic and more in line with the theory. They insisted that it was not, and even showed me their reworked tables that gave the acceleration along the vertical as being zero, which, of course, is not the case.

Since two of the group’s members realized belatedly that they were supposed to do the report for that experiment, I just suggested that they repeat performing the experiment so that they could reset the timer on the deductions of their report.

I think they will be having the make-up on Wednesday at 11am.

I also forgot to mention the faculty meeting last Wednesday, where we talked about academic advising (or flowchart/pre-enrollment consultation and approval), one of the full-time faculty members’ duties that takes up one week (the tenth of the term) during which students prepare for the subjects they are to take for the next term.

Despite the fact that “advising” is the phrase used even in books and movies I’ve seen about places like Oxford and Harvard, some of the faculty (particularly those who did not study in the system) have the mistaken impression that it’s akin to what a guidance counselor does of inquiring as to the student’s study habits and possible means of improving them. So the first half of the discussion was really to start calling it “pre-enrollment approval”, at least for the faculty’s residency form and calendars. More on the segue topic tomorrow that involved the subjects I teach.