The objective of this study was to facilitate inservice high school and university teachers' understanding of the difference between the terms "hypothesis" and "prediction." The context for understanding these terms was Columbus's discovery of America (as in the previous study). Control group teachers (N = 94) were evaluated before the discussion of these terms, whereas Experimental group teachers (N = 102) were evaluated after these terms had been fully discussed and elaborated in class. Results, based on written responses, showed that the Experimental group performed better than the Control group in elaborating both "hypothesis" and "prediction." The difference was, however, statistically significant only for "prediction". Despite improvement, almost 50% of the teachers still had difficulty in formulating a "hypothesis" and 40% in formulating a "prediction."