Konzeption und Evaluation eines Kinematik/Dynamik-Lehrgangs zur ...

268 9 Abstract
dents who answered more than approx. 60 % correctly (17 or more of the 29 items), what can be
seen as the threshold for Newtonian understanding, is with 42 % clearly larger than in the control
group with 16 %. The largest normalized gain was achieved in the subscale “Newton’s Third Law”
(43 %). The biggest effect size in comparison to the control group was attained in the subscale “understanding
of force” (d = 0.77). Thus it can be reckoned proven that clearly more students of the
treatment group have gained qualitative understanding of Newton’s concept of force.
The concept maps, which were prepared in three classes who were instructed according to the
teaching concept including modelling (n = 63), also prove that. In these concept maps students
showed qualitative understanding of Newton’s motion laws. Although two of the three classes only
prepared the concept maps at the end of the school year, these maps show fundamentally more understanding
than those of traditionally taught classes directly after dynamics instruction, and even
more understanding than traditionally instructed classes after an intensive intervention with modelling
(chapter 6.5.3). A class, which was taught following the new concept on kinematics and dynamics,
but without modelling, performed claerly better with the concept maps than traditionally
instructed classes, but not as well as classes that had dealt with modelling (chapters 6.5.3 and chart
7.9 under chapter 7.3.3.6). Especially modelling seems to help understand connections and to lastingly
embed them.
Finally the MPEX test (n = 125) was used to determine whether the students taught according to the
teaching concept had also changed their conceptions of the nature of physics, as well as their conceptions
of the way of learning physics. It turned out, however, that on average the instruction pursuant
to the teaching concept had no positive effect with regard to the dimensions of the MPEX test
(chapter 6.6.3). On the other hand, significant changes, mainly in the cluster “relation to reality”,
were observed in classes in which modelling was intensively dealt with: answers favorable to learning
of physics increased, and there was a decrease in the unfavorable answers (chapter 6.6.3). I.e.
for those students who were taught modelling, personal experience in the real world and in physics
instruction have more in common (chapter 6.6.3). This can be certainly ascribed to addressing real
processes with friction via modelling.
9.6 Summary
Dynamic-iconic representations can provide teachers with new teaching possibilities and thus help
students to adequately understand physical concepts. An introduction of kinematic quantities with
the aid of two-dimensional motions, which makes only sense with iconic representations in the form
of vector arrows (suitable elementarization), leads to a more physical understanding of the acceleration
concept and avoids misconceptions due to an inept reduction to the special case of motions in
one dimension. More students conceptualize acceleration – like in physics – as a directed quantity
instead of a quantity indicating the change of the magnitude of velocity and having at best tangential
direction.
This renders possible helpful representations for and thus reasonable changes of dynamics instruction
as well: In order to illustrate essential structures, more complex experiments with several forces
and friction are used, which is only feasible because of a computer-aided preparation with dynamic-