Functional thinking is an important concept in mathematics education. Numerous researchers examined problems and (mis)conceptions of students working with and learning about functions. In addition, the development of new technologies assisting the learning of functions resulted in the emergence of new aspects related to functional thinking. Dynamic mathematics software and resources based on this technology offer new opportunities for multiple, dynamically linked representations of functions. Therefore, it is important to examine how such dynamic representations influence students learning and conceptions related to functions. The study reported in this thesis particularly pays attention to the following research interests: the intuitive conceptions of students; the design of dynamic materials; and whether and in what ways dynamic materials may influence students conceptions. In this research project, I developed several dynamic worksheets applying the dynamic mathematics software GeoGebra. These materials were designed based on typical students problems and misconceptions outlined in literature concerning functional thinking. They address students conceptions and focus on the representational transfer between iconic situational model and graphical representation. In order to answer the research questions, I selected a qualitative approach. The overarching methodology is case study research but with integrated elements of Grounded Theory. The study was conducted in a 7th grade of an Austrian secondary school class. The developed dynamic materials were utilized during an intervention with 28 students aged 12 to 13. Several types of data were collected in this study including diagnostic tests, diagnostic interviews, students worksheets on paper, and observations during the intervention. These methods were arranged to a research design including five data collection stages: (1) diagnostic test 1, (2) diagnostic interviews, (3) intervention, (4) diagnostic test 2, and (5) diagnostic interviews. During the three-lesson-intervention, students worked in pairs with the designed dynamic worksheets without teacher guidance. Ten students were audio- and videotaped and the screens of their laptops were recorded. Afterwards, data was divided by source and analyzed applying methods acquired from Grounded Theory. Different levels of students conceptual understanding emerged during analysis of the first diagnostic test and interview data. These levels represent the translation process from situational model to function graph and include a comprehension gap for students between both representations. For each task of the first diagnostic test, several intuitive and incorrect conceptions appeared. In sum, participating students cover a wide range of different conceptions. ^Results seem to reveal that the extent of influence of these materials on students conceptions depends on the intuitive conceptions of students and their achievement level. During data analysis, the category perception emerged as a central issue of the students learning processes. The interpretation as well as the perception of the dynamic worksheets is further influenced by the prior knowledge of the students. Considering that students worked without teacher instructions, dynamic worksheets seem to be more appropriate for higher achieving students, whereas lower achieving students would probably profit of a teachers help to reflect their perceptions and interpretations.