The purpose of the research was to investigate the effectiveness of using multimedia as a means of teaching physical science to learners. The underlying theoretical assumption was that a multimedia presentation would help to reduce the cognitive load experienced by learners when they learn physical science content, compared to a traditional mode of presentation, and that this reduction may have a positive effect on the ease with which they master the content. Physical science learners in Grade 11 viewed a presentation consisting of multimedia screens and screens depicting the learning content in a traditional layout – in order to compare the level of knowledge gained as well as the cognitive load experienced for the multimedia and traditional instructions. Pre- and post-test questionnaires were used to determine the knowledge gained, while cognitive load was measured using a dual-task methodology. A multivariate analysis of variance was used to analyse the data. The results did not reveal a statistically significant increase in knowledge gained via the multimedia approach when compared to the traditional mode of instruction, but when focussing the analysis on learners with a lower-knowledge base in physical science though, statistically significant results were found. However, no significant results were found to support the hypothesis that multimedia would help to reduce learners’ cognitive load. It was concluded that the multimedia design principles are more effective in increasing knowledge for physical science learners of low-knowledge than traditional instructional designs. / M. Sc. (Psychology)