For some years, there have been in‐service efforts to help teachers become familiar with constructivist ideas about learning, and to apply them in their science teaching. This study is a vignette of one teacher’s science teaching some time after such an in‐service activity. It explores the ways in which the teacher implemented his perceptions of constructivist ideas about learning in his teaching of a topic. The extent to which the teacher used teaching principles based on constructivism was influenced by his views of science and of learning, how he usually planned his teaching, and his confidence in his own understanding of the topic. Features of the teaching which reflect a constructivist view of learning are discussed and some problems are identified. We conclude with some reflections about in‐service programs within a constructivist framework.

The view that knowledge cannot be transmitted but must be constructed by the mental activity of learners underpins contemporary perspectives on science education. This article, which presents a theoretical perspective on teaching and learning science in the social setting of classrooms, is informed by a view of scientific knowledge as socially constructed and by a perspective on the learning of science as knowledge construction involving both individual and social processes. First, we present an overview of the nature of scientific knowledge. We then describe two major traditions in explaining the process of learning science: personal and social constructivism. Finally, we illustrate how both personal and social perspectives on learning, as well as perspectives on the nature of the scientific knowledge to be learned, are necessary in interpreting science learning in formal settings.