Pre-Service Science Teachers' Understanding of Infinity Concept: The Case of Image on Convex Lens

Abstract

In this study, pre-service science teachers’ definitions of the concept of infinity were tried to be revealed and their understanding of the concept was tried to be examined through the image formation experiment in a convex lens. The study was conducted with 31 pre-service science teachers studying in the 3rd year of science teaching at a state university. Two separate scales were used as data collection tools in the research. The scales consist of open-ended questions designed to reveal pre-service teachers' definitions of the concept of infinity and to evaluate their knowledge about image formation and image properties in convex lenses in this context. One of the scales (Scale-1) was applied before the image formation demonstration experiment in the convex lens, and the other (Scale-2) was applied after the application. The data obtained from the scales were analyzed using the descriptive analysis technique. Pre-service science teachers’ definitions of infinity were grouped under three themes: general, mathematical and physical. Pre-service teachers mostly define and understand infinity with codes such as "unknown, undetectable, unmeasurable, undetectable, inexplicable, incomprehensible "under the "general" theme which includes the sub-themes of "unknown" and "having no end". This understanding of the prospective teachers leads them to the misunderstanding that the image of the object at infinity in the focal point of the convex lens is virtual and cannot be seen.