Background: The introduction of a new National Curriculum in post-apartheid South Africa heralded a different approach in education. This curriculum not only advocated the development of knowledge and skills, but also emphasised education for democracy and citizenship. It seeks to balance central control (and a single curriculum) with local design, by requiring educators to design curricula according to central guidelines and set outcomes. A science curriculum informed by principles of social, as well as critical constructivism, is more likely to meet the criteria as set out by policy makers. Purpose: The article reports on research conducted to probe learners' responses to a science curriculum informed by social and critical constructivist principles, and discusses the possible implications of such curricula for science education. Sample: A grade 6 class of 45 isiXhosa-speaking learners from a former black township in the Western Cape of South Africa were purposely selected for the case study. Participants were aged from 11 to 12. Most of them came from disadvantaged backgrounds. Design and methods: The article reports on a case study of one class of learners who were taught a science lesson series. The researcher taught the lesson series while the class teacher acted as observer in the classroom. The lesson series was based on the principles of social and critical constructivism. The lesson series was taught over four days for three hours every day. Data were collected as the series was taught. The entire lesson series was video-taped and focus group interviews were conducted with five different learners at the end of each day. Results: In this small scale, qualitative study, pupils' responses suggested that this approach allowed for greater participation by learners, as they had considerable input with regard to the chosen theme. Activities were learner-centred and drew on learners' everyday experiences. Although this was a series of science lessons, it was clear that the social issues also needed to be addressed in the lessons The strategy allowed learners to take ownership of their learning, as they could make choices regarding the curriculum. The response of the learners to this type of science curriculum raises questions about curriculum design, the nature of science and purpose of science education. Conclusion: A science curriculum informed by social and critical constructivist principles has the potential to facilitate the achievement of outcomes other than science outcomes. It allows for the personal and social needs of learners to be met and this may enable them to function more effectively in broader society.