In this paper we report on teachers' and students' participation in authentic science research in out of school time science clubs at elementary schools. In the program four to five teachers worked alongside practicing scientists as part of their research groups. Each teacher facilitated a club with 10-15 students who, by extension, were members of the scientists' research groups. Over the 3 years of the project nearly 30 teachers and over 500 children participated in the clubs. In this paper we present a case study of teachers and children who worked with an analytic chemist at a major university whose field of research is environmental arsenic. We illustrate how the professor mentored the teachers and how they in turn mentored the children. We show how the elementary school teachers who had very little formal science education gained the expertise needed to mentor the children. We found that in less than one academic year the teachers were able to gain the knowledge and skills to facilitate the children's legitimate participation in authentic scientific research; and that the children gained the methodological and intellectual proficiency needed to contribute useful data and findings to the scientist's research program.