The situated nature of the scientific learning requires studies on the role of phenomena exploration in order to activate conceptual change for the scientific and formal thinking (Guile & Young 2003; Vosniadou, 2008; Michelini, 2005, 2010). Design Based Research and Empirical Research are integrated in the framework of Model of Educational Reconstruction (Duit 2006) to individuate a vertical path facing the wide spectra of difficulties evidenced by literature on electromagnetism at different age students (Galili 1995; Borges 1999; Maloney 2001, Guisasola 2003). Rather than general results or catalogues of difficulties, we look at the obstacles that must be overcome to reach a scientific level of understanding. Milestones of a vertical path on electromagnetism and two examples of research based intervention modules on magnetic field properties in primary and secondary school are presented.
