This work presents an interactive system built to help teachers and students during a museum visit. We also present the interaction design process used to define the user interface. The system's main purpose is to help elementary and high school teachers to plan their students visit to a Museum. Using a portable device (Tablet-PC), the teachers can define a visiting guide with a set of questions that their students need to answer during the visit. The interaction was designed with participation of the PUCRS Science and Technology Museum staff and through many usability tests developed with the elementary and high school teachers.