La cámara oscura como recurso en la enseñanza de la ciencia por indagaciónanálisis de su efectividad didáctica

Resumo

The results of a qualitative study and focused on determining the effectiveness of the camera obscura as a didactic tool. The study aims to understand image formation (i.e., how it is possible to see objects and how their image is formed on the retina, and what the image formed on the retina is like compared to the object observed) in a context of a guided inquiry based learning (IBL) approach? The study involved 104 prospective primary teachers (PPTs), age range of 19-25 years old, grouped in 26 small working groups, who were being trained in science teaching on the second year of their 4-year-Bachelor Degree. The resource was used and assessed aiming the following inquiry questions: (1) What educational effectiveness does the camera obscura have for the PPT´s to improve their understanding of phenomena related to sight, in an IBL context?, (2) What do the PPT´s learn about teaching sight phenomena with the camera obscura, used with an IBL approach? Some qualitative techniques and instruments are used such as opened questionnaires (pre- and post-test), an inquiry notebook, teacher´s diary and semi-structured interviews. All the collected data led to draw relevant conclusions for the inquiry. The data were analyzed by combining methods of inter- and intra-rater analysis. The results showed that more than half of the PPTs advanced in their ideas towards the desirable level of knowledge in relation to the phenomena studied. The conclusion is that the camera obscura, used in a context of scientific inquiry, is a useful tool for PPTs to improve their knowledge about image formation, and first-person experience about an authentic scientific inquiry during their teacher training. This assertion is based on the fact that this resource, used in an IBL sequence, promotes the identification not only of the elements involved in sight, but also of the relationship between them, which latter is often more difficult. It also helps students to understand how an image comes to be formed on our retina, and what are its main characteristics in relation to the object observed. The PPT´s could observe by themselves, using only a simple device made of cardboard, how the images displayed on the screen of the camera obscura are inverted, with the up-down inversion being the most easily observed. In synthesis, we can say that the camera obscura used is indeed, an effective tool in PPTs' training from two perspectives: on the one hand, it favors their learning about the phenomenon dealt with (for a high percentage of the PPTs, it improved their conceptions about image formation). On the other hand, it lets them experience an educational resource to teach some optical phenomena in their future primary classes. Added to this, the contribution of the educational intervention with the camera obscura to their becoming familiar with the IBL approach, must be mentioned. This training promoted their identification of the IBL stages, starting with researchable questions concerning the initial posed problem. Finally, inquiry implications are drawn with a view to the training of PPT´s on the IBL approach. Limitations of the study, and perspectives on issues for future research are reported.