Information and Communication Technology has allowed the use of several types of visualizations, especially multimedia environments in science teaching. The aim was to investigate how in-service teachers enrolled in a training course understand the nature and the role of visualizations in science teaching as well as the impact of this training on the change of their conceptions. A questionnaire to identify previous conceptions has been applied. It was analyzed the Teaching Learning Sequence made by them and the audiovisual record of their speeches and semi-structured interview with these teachers’ groups. As the main result, we highlight development of the knowledge about these tools, especially on the impact of the visual language on apprenticeship and on the notion of scientific model.