This dissertation is an empirical study of the scientific literacy of 28 young adults (aged 18-26 years) in the context of their decision making about the health risks of mobile phones. The issue of possible health effects is one of a number of socioscientific issues now confronting adults in the 'knowledge/risk' society where scientific knowledge plays an increasingly significant role in people's lives. The focus of interest is the young people's responses to the uncertain science of 'science in the making' (Latour, 1987) and their positioning of this scientific knowledge in their risk assessments. The study is based on an interactive model of the public understanding of science and applies a critical realist and moderate social constructionist methodology. Data construction included focus groups and semi-structured individual interviews. The stimulus for discussion in the focus groups was a recent television news report presenting contradictory scientific research findings about whether mobile phones pose significant health risks. In the individual interviews understanding of the nature of science and risk judgments were explored. Data analysis involved a coding of the discourse in terms of themes and issues and interpretation of these in terms of the theoretical framework of the thesis. A major finding was that these young people interpreted the uncertainty of the scientific knowledge mainly in social terms and with limited understanding of the role of theory in interpreting data. They talked spontaneously of risk but did not draw on scientific knowledge or risk estimates in their judgment about mobile phone safety. Findings have important implications for science education and suggest a broadened conception of scientific literacy which includes critical dimensions and risk literacy. It is argued that this functional scientific literacy is essential for effective citizenship in contemporary society.