The given article discusses some descriptive analysis of such teacher actions that try to help students in classroom modeling processes in the way making the students to deal with difficulties as independently as possible. In doing so a classical principle of teaching is described which is also already mentioned by Maria Montessori, demanding "Help me to do it myself". To investigate this issue the intervention behaviour of four experienced teachers has been videotaped: once in an artificial situation (laboratory study) and once in a practical lesson (classroom study). For having been able to compare the teachers' special intervention behaviour of both, the laboratory study and the classroom study, the participating ninth-graders had to work on an identical modelling task in the laboratory study as well as in the classroom study. The results show that the four teachers do not only intervene because of student difficulties but do intervene nearly as often because of their own claims for the solution process. Furthermore it can be pointed out that small-step teaching aids often lead to students being able to solve problems and that the intervention behaviour between laboratory and classroom situations only differs slightly.