Abstract
This paper looks in detail at the understanding of school students in the UK of fundamental ideas about radioactivity and ionizing radiation. An adequate grasp of basic ideas in this area of science would be widely seen as an essential element of functional `scientific literacy'. A written diagnostic test was developed and administered to a representative sample of 16 year old students (n = 144). Analysis of their responses corroborates the results of previous research in indicating the widespread use of an undifferentiated conception of radioactive material/radiation and suggests that many students may hold a conception of the process of absorption of radiation (including ionizing radiation) which is significantly different from the accepted science view. This may have important consequences for their reception and interpretation of media reports and other public information about phenomena involving radioactivity and radiation.
