This paper investigates the process of teacher change in a group of 8 primary school teachers during their exposure to a science, technology and society (STS) approach to teaching Science in Swaziland. The research aimed to establish the effect of support given to teachers in using the approach through a series of workshops, followed by a 5-week supported implementation of the unit "matter and energy". An analysis of the way in which the STS approach impacted on the classroom practice of the teachers yielded 2 outcomes that were hierarchical. First, teacher understanding of the approach was observed to go through levels of unawareness, recognition of differences in approach, utilisation, personalisation and production. Second, the teachers' level of use of the STS approach was observed to have been affected by their levels of understanding, characterised by the following typologies: dropouts, strugglers, domesticators, succeeders and innovators. Some relationship between levels of understanding and typology of use was found, however, the level of understanding was not the exclusive determinant of typology of use. Only teachers reaching the utilisation level were able to use the innovation in a sustainable way, while those at the level of unawareness were able to become domesticators, adapting the innovation to their usual teaching approach.