We describe an ambient awareness tool, named Lantern, designed for supporting the learning process in recitation sections, (i.e., when students work in small teams on the exercise sets with the help of tutors). Each team is provided with an interactive lamp that displays their work status: the exercise they are working on, if they have called for help, since when, and on which exercise. Lantern, by providing this information, is meant to facilitate the interaction between tutors and teams, and to encourage collaboration among students. We report on a user study that examines the impact of Lantern on individual and group behavior in recitation sections. The results show how Lantern can improve the efficiency of tutor-teams interaction, increase the intrateam collaboration, and improve the structure of interteam communications. On the other hand, having a minimalist design, and being embedded in the classroom environment, it avoids diverting the focus of students from their main task and fades quickly in the periphery when not used.