Prospective elementary teachers' prior knowledge about light

This article reports on a study that was designed to describe prospective elementary teachers' prior verbal and diagrammatic knowledge about various aspects of light, seeing, shadows, and mirror images. Data were collected through individual interviews using simple apparatus (light bulb, objects, screen, and plane mirror). Included are some inferences about how students' ideas may have emerged from their interpretations of everyday experiences. The article concludes with a section that provides an example of a conceptual change instructional strategy that was based on the research results reported here.