Abstract. The goal of this work is to explore the relationship between pervasive software and user engagement towards environmental issues. We study this relationship in the context of an art installation that concerns the water cycle in nature. The research question is: How can we design and evaluate software that becomes a medium to engage and inform the user? We have gathered empirical data during a two days exhibition of two versions of a pervasive art installation by: observations, questionnaires, and input logs. Data analysis reveals that the art installation engaged users, with focus on young children, and communicated the intended message. The results are organized according to five important factors for developing and evaluating interacting art installations. These are: 1) data collection method; 2) user interaction; 3) social interaction; 4) issues about children; 5) message comprehension. We suggest that these factors can inform engineering practices for engaging software like video-games.