Uni Fakultäten Fk. V Physik Didaktik und Geschichte der Physik  

Conceptions on Mechanical Waves - a historic educational reconstruction-

Abstract

This study focuses on students’ conceptions of mechanical waves as a basis for physics teaching and was conducted in the context of the conceptual change discussion of the late 90’s, which evolved from conceptions research in the late 80’s.
In the first part of the study, the author develops a definition of students’ conceptions and argues for the use of the model of Educational Reconstruction (see Duit, Gropengießer & Kattmann 2005) as a research and development programme in the conceptual change discussion.
This discussion emerges from a comparison of different conceptual change theories. Furthermore, the author develops a historic educational reconstruction based on the model of Educational Reconstruction. This particular model was used as the study’s framework and encompasses the following research objectives: comprehension of students’ conceptions, scientific historical clarification, and historic educational construction. These objectives are connected in interdependency and can, therefore, inform each other and bring about change.
The first objective, the comprehension of students’ conceptions, was explored by interviewing students at different secondary school grade levels in one-on-one interviews. The interview implementation and analysis followed the student conceptions oriented interview, an innovative method developed by the author. One key aspect of this method was to record – besides talking – facial expression and gesture of the students with a video camera. This allowed transcribing the interviewees’ body language as important part of the interview data and its later analysis on mul-tiple levels. The analysis resulted in a typology, which was developed to categorize students’ conceptions: Type A describes conceptions, which encompass the propagation of waves as a horizontal transportation of particles. Type B comprises students’ conceptions describing that water particles remain at their horizontal location but move vertically. Most of the students belong to the A-type.
The second objective of the model is the scientific historical clarification. The investigation is carried out with textbooks from the history of physics. The aim was to reconstruct the historical genesis of mechanical waves in science. The analysis showed that early scientific concepts of mechanical waves are similar to students’ conceptions which were found in the interviews of type A. Especially early concepts from the 16th century on when scientists defined the propagation of a wave as a hitting or pushing process are similar to these students’ ideas. In the 1850’s, after Weber and Weber published their textbook Wellenlehre (Weber & Weber 1825), the energy concept was established as a new paradigm in the scientific community. Ever since, the explanation of the wave propagation was interpreted as a form of energy transportation in the scientific community. In this study, it could be demonstrated that the historical genesis of the wave concept is consequently intertwined with the development of the energy concept.
The third objective, the historic educational construction, is focused on implementing the history of science in physics instruction in school. Therefore, potential key suggestions for physic lessons are provided on the basis of the study’s results. It is demonstrated, for example, how ideas from the field of history of science can be successfully incorporated into physics lessons plans for secondary school students. A particular concern was how historical experiments can be used in demonstrating the energy concept within wave phenomena. The suggested historic educational reconstruction has the potential to foster fruitful learning connected with conceptual changes, especially when aspects of history of science are integrated into physics education.