Many students in physics courses fail to achieve a desired conceptual change because they assign an incorrect ontology to the to-be-learned concept. This situation has been detected in previous research for the case of field lines: many college students assign material properties to the lines and describe them, for example, as tubes that contain or transport charges. The historical evolution of this concept shows that early scientists like Faraday assigned material properties to these lines in some occasions. In the present work a history-based instructional material was designed to foster the analysis of the ontology of field lines to help students at an Argentinean university achieve conceptual change. The predicates used by the students to describe physical situations were used as evidence of the assigned ontological status. Conceptual change was measured by the change in the proportion of geometrical predicates that students used when referring to the lines in a written questionnaire. This change was significantly higher for the students learning with the history-based material compared to those that learned in the regular class. Some characteristics of the material and geometrical ideas that students hold about the field lines were determined through an oral interview. © 2006 Wiley Periodicals, Inc. J Res Sci Teach