Chemistry 312 is a one-semester course for non-chemistry science
majors
that meets for three 50-minute classes per week, and has one four-hour lab
per
week. Semesters are 13-14 weeks
long. Over the past three years
as
a result of curricular revisions catalyzed by (a) the award of an NSF-ILI
grant,
(b) the publication of the NSF’s Curricular Reforms in the Analytical
Sciences
and (c) my involvement in STEMTEC, the local NSF-funded center for
excellence in
teacher preparation, ‘research projects’ have been introduced into the
laboratory class, cooperative learning situations have been ‘imposed’ on the
students in the ‘lecture’ class, and students have been encouraged to work
cooperatively outside of the classroom on homework exercises, lab reports,
and
the K-12 teaching experience.
The results have been encouraging in that (a) the performance of the
students, as evidenced by the distribution of letter grades awarded, has
significantly improved since these modifications were introduced, and (b)
student feedback about the pedagogies employed have been generally (though
not
100%) positive. It is also
clear
(though the numbers involved are small) that students who do not connect
with
other members of the class are often the ones who withdraw.
The response to the requirement to interact with K-12 classes has
been
uniformly positive.
The last three periods of the laboratory class have been given over
to a
research project. A significant challenge for the instructor has been to
devise
projects that are (a) ‘real world’, (b) are not so challenging that no
progress is possible with the limited equipment and time available, and (c)
not
so trivial that they do not catch students’ interest.
This year, project topics were given out two weeks prior to the first
project lab period, and preliminary background reading and suggestions for a
plan of work (together with details of chemicals and solutions needed) were
required as a graded homework exercise whose deadline was just prior to the
start of the project. Six
projects
were assigned. These
involved
the development of an analytical method, followed by validation and
application
to a real sample material. As
far
as possible, the exercises were constructed around a ‘problem’ which, for
its solution, needed information about the chemical composition of relevant
materials. For example, one
project
involved testing the hypothesis that cigarette butts are a significant
source of
environmental contamination by phosphate; another project examined the
extent to
which nutritional elements were extracted from tea leaves by soaking in hot
water. A report in the form of
a
short paper for a research journal was required.
The success (or otherwise) of this part of the course will be
described,
information from the students will be presented, and some critical comments
made
as to whether such exercises are the best use of class time.
One issue that only surfaced about half way through the semester was
that
students did not have the mastery of some basic chemical facts and concepts
that
I thought they would have as a result of taking the prerequisite courses of
general chemistry and organic chemistry, even though an early diagnostic
homework on relevant topics showed no difficulties.
The most critical manifestations of this problem were that students
were
not only very slow to perform basic calculations concerned with
concentrations
and dilutions, but were also prone to make errors or to make inappropriate
choices of masses and volumes of relevant chemicals and solvents.
Thus, a disproportionate amount of laboratory time was spent on these
preliminary aspects of the experiments. This
suggests that too much detailed information was being provided in connection
with the earlier experiments.
Even
though students had performed several experiments already in the lab before
the
projects started, they had not, apparently, improved in terms of the speed
with
which they could perform appropriate calculations nor in terms of the
reliability with which they could make decisions about basic
procedures.
This experience suggests that additional tutoring is needed.
One possibility is that material could be delivered via the web in a
manner similar to that for the OWL material already developed in the
Chemistry
Department in connection with general chemistry, and currently under
development
for use with sophomore organic classes. Delivery
in this form could have the advantage that revision of these basic concepts
and
skills would not take up class time--currently, I am devoting 10-15 minutes
of
every ‘lecture’ class to such remedial topics--though I am finding that
unless I test the students in class under my supervision, I do not get
accurate
information about their abilities.