This paper presents the development of an experimental methodology for empirical and participatory ethics of science and technology. It is designed to detect, understand and mediate public concerns. Science and technology evolve rapidly as a result of their internal dynamics as well as the optimization of subsidy for research and innovation in recent times. Ethical frameworks for governing these developments are confronted with considerable tensions in mediating the velocity of new innovations while securing more robust institutional guarantees in order to manage and regulate in time. We argue that existing frameworks need to evolve to become more sensitive to the diversity of technological and societal challenges, of envisioning futures, and of what counts as legitimate concerns. For this reason, we give socio-technical imaginaries a key role in developing an ethical framework. Our experimental approach is seeking to establish criteria for mediating a wide range of public opinion in ways that can become embedded in legitimate, institutional procedures. Our methodological approach is also seeking to mediate between lay ethics and the discourse of professional ethicists, recognizing the fragmented character of both. We draw on theoretical constructs in current STS research, notably, those dealing with complex relations between communities, real or imagined, and the rise of new publics whose voices can be distilled and heard through mediating channels. This experimental methodology forms the central component of an ongoing European Union FP7-funded project, TECHNOLIFE.