University student understanding and reasoning on work-energy relations

An understanding the general principle of work and energy (GPWE) is essential to apply work and energy relations in general physics courses. In this paper, students' reasoning about the GPWE is analysed in a social-constructivist theoretical framework of conceptual understanding and reasoning. We designed a questionnaire with open-ended questions to detect students' difficulties with the concepts involved. The responses were analysed by defining explicative categories for student understanding. We have identified 'intermediate frames' for understanding GPWE. The 'intermediate frames' that students construct halfway between their prior knowledge and scientific understanding include reasoning, such as (a) considering superficial features and incorrectly analysing particular cases (b) not considering that the application of the GPWE is only valid in a previously chosen system.