Aspects of understanding electricity : proceedings of an international workshop : an inventory of research results concerning the representation of students' knowledge of electricity and its uses for the improvement of teaching : Ludwigsburg, Sept. 10 to 14, 1984 / sponsored by Volkswagen Foundation ; Reinders Duit, Walter Jung, Christoph von Rhöneck, editors / Kiel : Institut für die Pädagogik der Naturwissenschaften an der Universität Kiel , 1985