of truth methodology as justification inductivism robabilistic inductivism methodology as convention conventionalism ypothetico-deductivism methodology as decision "anything goes" modelling intervention & methodologies: method(s) contexts & values: community consensus demarcation & structure: science is methodical normativity & recursion: science should be methodical Figure 1. The matrix of stages and strands permits tracing the evolution of meta-theoretical ideas and their relationship with big conceptual axes. The example of scientific method is shown here. The theoretical apparatus that I have briefly described here has allowed me to identify central NOS ideas for science teacher education (Adriz-Bravo, 2001c, 2005a, 2005b, 2006). I will show in the next section how I have designed specific didactical units to teach those key-ideas to science teachers. My units follow earlier research-based suggestions that NOS contents can be successfully taught using memorable episodes from the history of science in the format of case studies (Duschl, 1990; Irwin, 2000; Matthews, 2000; Seroglou and Koumaras, 2001). Didactical proposals to teach NOS to science teachers This section exemplifies three self-contained sets of teaching activities (i.e. didactical units) that I have constructed to acquaint prospective teachers with relevant aspects of NOS. The first unit revolves around the construct of image of a scientist . It aims at discussing the ways in which lay people see scientists ranging from scientific heroes to unknown science workers. Issues of social importance such as scientism , elitism and sexism are discussed. The second activity uses introductory logic in order to characterise decisional aspects within the scientific method,