A review of the papers published in science education shows that the teaching centred in modelling is seemed as one of the most effective strategies for the improvement of the understanding of scientific concepts. However, a more carefully analyse also shows that what is being called as model or modelling process is very wide, and does not consider the differences in the specificities of the sciences. In this paper we try to discuss the differences and similitude in physics and chemistry modelling, having as reference the different explicative traditions in both sciences in the XVIII and XIX centuries. Finally, we discuss the didactic consequences of having in mind, or not, these differences.