The Oil Drop Experiment: Do Physical Chemistry Textbooks Refer to its Controversial Nature?

Abstract

Most general chemistry textbooks consider the oil drop experiment as a classic experiment, characterized by its simplicity and precise results. A review of the history and philosophy of science literature shows that the experiment is difficult to perform (even today!) and generated a considerable amount of controversy. Acceptance of the quantization of the elementary electrical charge was preceded by a bitter dispute between R.A. Millikan and F. Ehrenhaft, that lasted for many years (1910–1925). The objective of this study was to investigate whether physical chemistry textbooks refer to the controversial nature of the experiment. Based on six criteria developed previously, 28 physical chemistry textbooks were evaluated. Analysis of the texts using six identified criteria demonstrated that the textbooks neither referred to the controversial nature of the experiment nor recognized the difficulty of the experimental procedure. Only a few texts even attempted to include any discussion of the history or philosophy of the experiment. The instructor of a physical chemistry course could include aspects of the Millikan–Ehrenhaft controversy to motivate classroom discussion and help facilitate an understanding of the role that controversy has in scientific progress.