Abstract
In the light of the new curriculum, this study describes how grade 7 and 8 students in South Africa engaged with the notion of size and scale in the Solar System and beyond before, during and after a visit to an astronomy science centre. Using a combination of concept maps, observations and interviews, results indicate that, despite contrary suggestions in the literature, students aged 13- to 15-years are able to improve their conceptions from naïve and conflicting knowledge to a more scientific understanding of mass, size and distance after their visit. The paper argues that a combination of related, themed experiences related to size and scale can account for the improvement, and recommends that such activities should be explicitly promoted at science centres.