Background:
This paper reports on one part of a larger study which aimed at testing the effectiveness of an interactive optics teaching module in enhancing Grade 11 learners’ conceptual understanding of reflection. The focus of this paper is to evaluate the effectiveness of a part of the interactive optics teaching module in enhancing learners’ conceptual understanding about the characteristics of the image formed in a plane mirror.

Materials and methods:
The sample consisted of 70 learners, selected from one school in the Eastern Cape Province in South Africa. Within the quasi-experimental design, the data were collected from four relevant questions of the questionnaire (designed for the larger study).

Results:
Findings indicated that the designed teaching module was effective in enhancing learners’ understanding of image formation by a plane mirror.

Conclusions:
A teaching approach which included the ray diagram approach as in the present study could not be located in any of the previous studies. The sequentially-arranged questions designed to create cognitive conflict led the learners to create a stronger conceptual understanding of the characteristics of the image formed in a plane mirror.