The purpose of this study was to classify the types of scientific concepts by theoretical concepts and empirical concepts in physics, and to create cognitive conflict in students with logical statements and demonstrations, and to investigate conceptual changes. It seems that mechanics has much to do with the empirical concepts, and electromagnetics has much to do with the theoretical concepts. The condition of the instrument is intellegible, plausible, fruitful, and able to state and demonstrate. The instrument appropriate for these conditions was developed, which consisted of 6 items in mechanics and 6 items in electromagnetics, and conceptual changes were investigated. Structured interviews were conducted with 32 high school students to create cognitive conflict. We have elicited their ideas three times : pretest, posttest and delayed posttest. As the results of this study, demonstration method was more effective for conceptual change than logical argument method. In case of content areas, the misconceptions on mechanics concepts were changed more easily than those on electromagnetics concepts. In addition, the results of the study showed that the more cognitive conflict, the more the conceptual change was occurred.