The present work presents an experimental guide to evaluate temperature’s changes in a system when energy through heat is transferred and relate those temperature’s changes with the variables that take part before the phase transition. This proposal is part of several activities presented in a Research Project which proposes, taking energy as a guide, to elaborate, to implement and to evaluate didactic strategies at First and Second year of Polimodal at Instituto Maria Auxiliadora from Santa Rosa La Pampa, Argentina. In order to elaborate this laboratory guide we based on two relevant aspects: on the one hand, to give continuity to concepts like energy, system, internal energy, heat and mechanical work as a transference process that modify the system energy; and, on the other hand, to implement prediction, observation and contrasting stages, typical of Active Learning. We believe that this proposal will allow us to combine new concepts taught at Second year with the ones already taught at First year referring to energy, obtaining a wider and unified vision of the Science and, particularly, of Physics. The methodology utilized could be a valuable tool in order to favor the significant learning