Abstract
The purpose of this study is to explain the in-class and out-of-class application process of a modeling activity and to reveal the similarities, differences and limitations between these applications. In the qualitative multi-case study, two different situations, namely in-class and out-of-class application of modeling activity, were discussed. The data of the study were obtained from the solution papers of the students in the in-class activity application, the reflective diaries written after the activity application, the solution papers of the students participating in the out-of-class activity, the voice recordings during the solution process and the post-application interview. The field notes were kept in both applications by the researcher. The solution papers were analyzed in the context of the modeling process. While the reflective diaries of the students were coded with content analysis, the interview conducted in the out-of-class application was analyzed with the descriptive analysis. The in-class application, the students tended to solve the problem without creating a model and could not fully verify. In the out-of-class application, the students made more realistic assumptions and established more complex models. It is recommended to integrate the in-class and out-of-class applications of modeling activities.