I just got done grading and handing back lab reports in which students
took some measurements of A as a function of B, and the expected
relationship is A is porportional to B^2.
In past years the lab handout stated the students should construct a
graph of A as some function of B that would allow them to make a
convincing argument that the theortetical prediction is valid.
Of course I expected them to plot A versus B^2, and get a reasonably
straight line, and comment on that in their conclusion. Of course what
I got was all over the map.
I got so tired of poor reports that I changed the handout so it now
says. "Plot A versus B^2 and see if you get a straight line as the
theory predicts. Remember this means plot A as a function of
B-squared." But results were still all over the map.
When I talked individually to students about why they didn't do what the
directions stated, I got a variety of responses that support what Tim
and Rick have already mentioned. In no particular order, here are some
responses:
(1) Oh, I don't read the lab handouts because I can never understand
them. I just ask someone else in the class what we're supposed to do.
(2) I did read the handout, and it didn't make any sense to me, so I
just used my own judgment about what we were supposed to do. [Which
might not be so bad if the student took the time to develop some good
judgement about the goal of the experiment and how one might reach that
goal.]
(3) I thought I did plot A versus B^2. [The student had plotted B^2
versus A because s/he didn't understand the language. One third of the
class plotted (some function of B) versus (A) rather then (A) versus
(some function if B). This ocurred even though time and time again I
have told them that A as a function of B means the same thing as A
versus B, and these mean A on the vertical axis and B on the horizontal
axis.]
Conclusions:
Many students don't read. Many students can't read critically and
understand what is written. Students don't listen. Students would
rather copy someone else in the class. I have office hours, but
students won't come to office hours to ask questions.
John Clement said, "One needs to change the conventional structure to an
inquiry mode with frequent communication between students, and students
and teacher."
You can't do this if students refuse to do anything outside of class,
because in-class time is way too short for accomplishing the goals of
the course. It goes back to something I've said before: I expect
students to read assignments outside of class. I expect students to do
experiments outside of class. I expect students to write outside of
class. I expect students to solve problems outside of class. I expect
students to come to office hours if they have questions. But today's
students think I am totally unreasonable. If I can't teach them what
they need to know about physics within the contraints of five 50-minute
class periods a week for 30 weeks, then I must be a lousy teacher. They
don't have any more time to spend on physics than class time. Since
they have become accustomed to teachers that don't demand out-of-class
work, they can't read, they can't write, they can't solve problems...
because they don't have any practice doing these things. And they fill
their out-of-class hours with sports, TV, socializing, etc. and think it
is an unreasonable intrusion if I want them to spend some of that time
doing physics.
The proponents of inquiry mode appear to mean "inquiry mode in class
only." For a 5-credit class I want 15 hours per week of inquiry mode...
Some of it during class, some of it during reading, some of it during
writing, some of it during labs. I'm lucky if I can just get them to
class for all 5 class sessions.
I agree different teaching methods can have an effect on learning, but
it's hard for any method to have success if the students aren't willing
to spend the required time. You learn to read by practicing. You learn
to write by practicing. You learn to shoot free throws by practicing.
No problem there. If students would spend 10-20% of the time on physics
that they spend practicing their sport, I wouldn't be complaining.
Michael D. Edmiston, Ph.D.
Professor of Chemistry and Physics
Bluffton University
Bluffton, OH 45817
(419)-358-3270
edmiston@bluffton.edu