The use of computer-based educational tools is increasing fast and it can be predicted to become extensive or even dominant for a number of functions. On the other hand, there are functions that can never be replaced by multimedia tools, and can only pertain to a teacher. In the case of science education, these functions relate to the building of the perception of what science is and how it proceeds, to the stimulation of fundamental curiosity attitudes, to the development of logical reasoning (including inherent language-of-science aspects). This implies a refining of the role of the science teacher to emphasize these functions and interface and balance them with the functions that are increasingly delegated to computer-based options. The paper includes reflections on the features of this “refining”, substantiated by the consideration/analysis of concrete examples from current classroom practices and from diagnosed students’ difficulties specifically concerning the functions that are inherently human-pertaining. It is expected to contribute to the educational investigation for the design of approaches aimed at maximising both the benefits of computer-based tools and the fundamental roles of the science teacher.