Secondary students' mental models about the soil

This paper presents a case study whose purpose was to investigate the alternative conceptions and the students' mental models about the soil. The participants were 48 students of 10th grade. Data were collected by an open-ended questionnaire focused on the soil origin, age, constituents and changes which it could undergo. From an inductive analysis of the participants' explanations, the conceptions and the mental models were identified. The results indicate that this group of students presents three types of models about the soil: primeval soil, geological soil and ecologic soil related with the cycle of matter.