Page 79 - Cultural Studies of Science Education

56 W.-M. Roth

length depends not only on the material but also on the temperature difference and
1
on the length of the material. Thus, I modified the experiment so that students
could pour water of different temperatures into a funnel allowing them to produce
different temperature differences (i.e., ∆T). I also asked them to bring the needle
pin to different distances within the clothespin, which varied the effective length of
the expansion which was measured. The students now conducted several experiments
over the course of nearly 2 weeks, in which they varied the different parameters,
noted their results, produced graphs, and so on. I learned from this experience that
with a little innovation, the use of any equipment or any experiment could be
extended for the benefit of student learning.
I designed and produced other novel learning resources, such as, for example, a
slide rule for assisting students in doing or checking their multiplications and divi-
sions. In those days, calculators were expensive and slide rules were slowly going out
of fashion. Because I noted that the students had difficulties with their multiplication
and division, I asked the janitor to help me build a giant (8-ft) slide rule, which
I painted and marked off in an appropriate manner to be able to do multiplication and
division (this requires a logarithmic scale). I not only taught my science students how
to use it, but also had them employ it for their own applications.
In the seventh-grade biology course, we had a heyday. Nature was just outside the
entrance door (Fig. 1), and all I had to do was come up with some useful curriculum.
One aspect I felt students should learn is doing scientific research. Every week during
our double period, which took all afternoon, we went outside to do experiments.
Students learned about random sampling using hoops homemade from wire clothes
hangers; students tossed these behind themselves and wherever the hoops fell they
sampled plant and animal life. We manufactured 1 by 1-m squares from four wood
strips and thereby produced a tool for conducting systematic counts of plant life
within the same reference area. We used a 100-m long string, which we marked off
in 1-m intervals to produce a reference line for strip sampling. Once the students had
learned these techniques on the hill behind the administration building and teacher
residence, we were ready to go out and sample different kinds of ecological succes-
sion processes – bare rock succession, forest fire succession, pond succession, and
so on. A succession is an orderly change from one type of ecological (plant, animal)
community to another type. They exist both diachronically, for the same area over
long periods of time, and synchronically, with geographical variation. Thus, for
example, by laying a strip from a forested area to a pond, students were studying the
different plant and animal communities in places where there used to be a pond; or
they studied bare rock succession by going on a rock outcrop and then sampling
along a strip into a nearby grove. Given that nature started right behind the school,
there was so much we were able to study just with the few simple techniques that
students increasingly honed as they participated in using them. How often do city

1 The formula for the thermal expansion ∆l of a rod with length l is ∆l = kl∆T, where k is a constant
characteristic of the material, thus different for glass, aluminum, copper, steel, etc. and ∆T is the
temperature difference.