FROM CATHODE RAYS TO ALPHA-PARTICLES TO QUANTUM OF ACTION - A RATIONAL RECONSTRUCTION OF STRUCTURE OF THE ATOM AND ITS IMPLICATIONS FOR CHEMISTRY TEXTBOOKS

Research in science education has recognized the importance of the his tory and philosophy of science. Given this perspective, it is importan t to analyze chemistry textbooks, at the freshman college level, to de termine the degree to which they deal with recent developments in the history and philosophy of science. This study has the following object ives: (a) elaboration of a framework, based on a rational reconstructi on of developments that led to the formulation of atomic models by Tho mson, Rutherford, and Bohr; (b) formulation of eight criteria based on the framework that could be useful in the evaluation of chemistry tex tbooks; and (c) evaluation of the textbooks based on the criteria. Twe nty-three textbooks were evaluated on the eight criteria. Results obta ined show that most textbooks emphasize experimental details based on observations, leading to the presentation of scientific progress as a rhetoric of conclusions, based on irrevocable truths. Such an understa nding lacks the conceptualization of the heuristic principles that led the scientists to design and interpret their experiments. For example , in the Case of J. J. Thomson's work, besides the experimental detail s of cathode ray experiments (emphasized by most textbooks), the ''heu ristic principle'' involved the testing of rival hypotheses, namely a determination of the mass-to-charge ratio would have helped to identif y cathode ray particles as an ion or a universal charged particle. Mos t textbooks presented the experimental details, without the conceptual ization that progress in science is based on competing frameworks of u nderstanding that clash in the face of evidence. It is concluded that textbooks should emphasize not only the experimental details but also the ''heuristic principles'' required to ''structure inquiry.'' (C) 19 98 John Wiley & Sons, Inc.