Sequência didática sobre um caso limite do empuxo de Arquimedes: o paradoxo hidrostático de Galileu

Abstract

Science is dynamic; at every moment, well-established paradigms are challenged. Furthermore, the models developed to explain physical phenomena are generally limited. However, it is not uncommon to encounter textbooks that present theories and statements as if they were definitive, without the need for updates, and that do not address the edge ases of these theories. An example of this is the buoyancy of bodies, where many textbooks present Archimedes' principle in a way that generates contradictions, such as in the case where a container holds a volume of liquid that weighs less than a specific object, and yet the object is able to float. This exemplifies Galileo's hydrostatic paradox. Therefore, to awaken in both teachers and students the need for a reflective-critical stance when presenting a physical theory, we developed this work, which consists of a didactic sequence about Galileo's hydrostatic paradox, in which we propose a low-cost experiment to illustrate this intriguing physical situation. The methodology of this work was based on the Three Pedagogical Moments (3PM) proposed by Delizoicov, Angotti, and Pernambuco. The developed educational product was applied in a class of a fully integrated high school at a Federal Institute of Education, Science, and Technology. As a result, we observed a reduction in the percentage of students' mistakes in questions about the problem of floating bodies after applying the didactic sequence. Additionally, students reported that they were unaware of Galileo's hydrostatic paradox and expressed great interest in the demonstration conducted. They stated that the experimental practice developed contributed to a better understanding of the content and increased their motivation to participate in classes. Thus, we believe that the didactic sequence developed here can be an important tool for teachers who wish to teach both Archimedean and Galileo's buoyancy.