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

264 9 Abstract
learned. Moreover, 83 % of the students agree with the statement that the point of a physical problem
is finding the correct equation. The graduation of the items into the different subscales can be
viewed critically, however, due to factor analysis and reliability analysis. It was furthermore observed
that there is a certain coherence between the conception of the nature of physics and of
studying physics on the one hand and the understanding of the Newtonian force concept on the
other hand, respectively, there is however no coherence between these conceptions and the normalized
gain in learning in Newtonian mechanics (chapter 6.6.4).
All in all this means that traditional mechanics instruction underachieves by far and results in only
little qualitative understanding.
9.2 Ideas of the developed teaching concept
Dynamic-iconic representations illustrating physical quantities in motion allow the teacher to present
physical quantities and statements in different ways (chapter 3.2). The temporal process of a
physical quantity as well as the interrelations between different quantities can be displayed on different
abstraction levels. Within the developed teaching concept dynamic-iconic representations
were used as an auxiliary means to change students’ conceptions, especially the representation of
vectorial quantities by dint of vector arrows.
This allows for an introduction to kinematics via a general two-dimensional motion, with which
kinematic quantities are introduced (chapters 5.3.1 – 5.3.2). Thus the students become acquainted
with the vectorial nature of the quantities velocity and acceleration. The examination of the vector
“change in velocity” v �
∆ can furthermore be seen as the elementarization of the acceleration vector.
For the acquisition of measured quantities of two-dimensional motions four different possibilities
are suggested (chapter 5.3.3), whereas the PC-mouse is mainly used for implementations in class as
well as for student exercises.
In dynamics, this representation and continuous measurement can show that the Newton’s Second
Law applies at all times, even under the condition of variable force. Experiments with several forces
and friction forces as well as more complex experiments on Newton’s Third Law are also possible
� �
(chapters 5.3.4 – 5.3.6). Newton’s Second Law is being outlined in the form a = ΣF
/ m .
Iconic representations can also be applied in qualitative exercise- and test problems requisitioning
understanding. The representations moreover provide for demanding exact predictions from the
students previous to conducting the experiments (student activities), mainly regarding relevant
quantities and regarding the arrows representing them, with their directions and changes (chapter
5.4.4). That way, students can be again and again challenged to actively think.
Another iconic representation is used for creating networks of variables and relations (we call them
“effect networks”) in order to make all interdependences of the quantities and thus structural interrelations
clearer (chapter 4). These networks of variables and relations can be automatically implemented
into a computing program by a software for graphic modelling, and the physical progression
can be calculated. Creating models on dynamic sequences helps to clarify own conceptions of structural
interrelations, and the progression with animations gives feedback. That way, misconceptions
are cleared and the few basic equations of mechanics are emphasized.