There has been increasing evidence of the positive effects in informal science programs to promote the youths' positive development. However, relatively a small number of informal science programs target specific student populations such as youth in poverty with little research done about the important program factors. This case study presents an exemplary informal science education program (focusing on Earth Science Education or more specifically, water in urban environments) for youth in poverty in a midwest city of the United States. This study explored the most important characteristics of the program that could lead to positive development for the youth. Through a number of observations of the program and interviews with the participants, this study employs inductive and interpretive research methods. Findings show that the program managers' beliefs about the youths' knowledge and experiences, their relationship building skills, and their cooperative work are very important. A concrete mission for the program and structured institutional support to hire the youth as paid museum staff are also important in assuming their responsibility and building identity as an active social member.