This work presents the results of a teaching strategy based on Projects Based Learning which was applied in a course of Electricity and Magnetism for engineering students of the Colombian School of Engineering in the first semester of 2015.The students were required to construct low cost prototypes that let them to use concepts of physical modeling and error theory.The methodology employed stimulates and increases the learning of electrostatics and of other abilities such as graphical, oral and written expression.This paper describes the method used and the instruments that were used for the data collection process.Analyses show a gain of (0.78 ± 0.03) and (0.65 ± 0.04) for the evaluation of the projects and (0.47 ± 0.04) for an electrostatic conceptual test.The paper presents and discusses the strengths and difficulties of the strategy employed.