In the 1980s, Chevallard investigated the transformations of the scientific knowledge to become teachable, and called this process "Didactic Transposition". In science textbooks, this process generally involves the logic organization of contents, which removes the concepts from their historical and philosophical origins. This out-of-context didactics, besides giving rise to mistaken images of the nature of science and the scientific inquiry, fails as well when it inadvertently uses some concepts foreign to the original conceptual background, taking the history of science as merely introductory content. In this paper, the didactic transposition of radioactivity, which is present in a textbook widely used in disciplines such as the structure of matter, for future teachers and scientists, is analyzed.
didactic transposition; history of science; radioactivity; textbook