This study aimed to teach 9th grade students the meanings of scientific theory and scientific law, and the differences between them. The related literature informs that students at different grade levels have misconceptions about the definition of both scientific theory and scientific law and the relationship between them. In this study, the teaching activity emphasized that the characteristics of scientific theory and scientific law are different. The activity was carried out in five groups, each with 5 students forming a sample of 25 students. The first part of the activity emphasized that scientific laws are in fact the simplest form of relations and generalizations. The second part focused on scientific theories emerging from inferential explanations. This activity is important in terms of supporting conceptual understanding of the students and teaching that scientific theories and scientific laws are different kinds of information and that scientific knowledge are open to change.