The role of context in learning has taken on a new significance in recent research in that it might account for the "lost learning" that should result from the school experience, but which does not appear on normative assessments intended to measure learning in areas explicitly valued by society. A naturally occurring microworld, or pocket, in the social fabric is examined to look at the phenomenon of learning within a domain where bracketing is naturally afforded by the practices involved. Like traditional schooling, recreational scuba diving has its own formal curriculum and schooling, as well as an informal participation structure and communities of practice. Using a mix of research methods, largely ethnographic, the effectiveness of the formal diving curriculum and the Legitimate Peripheral Participation learning theory of J. Lave and E. Wenger (1992) are assessed to account for the participation patterns observed in recreational diving. Results are examined for implications in larger educational settings. Ten figures illustrate the discussion. (SLD)