This article analyzes the activity "Daytime School Guided Visits" at an astronomical observatory in Brazil with pupils from primary school. The adopted research methodology relied on questionnaire applications and semistructured interviews. The objectives were to identify the influences of the visits on learning of astronomical concepts and on pupils' motivation toward science. This study showed that it is difficult for children to understand scale distances in the Solar System and beyond. In order to cope with this problem, this article highlights the relevance of science centers' partnership with schools to achieve the goal of improving scientific education by relying on two main participants for a successful visit to a science museum: Guides and teachers. (Contains 3 figures and 1 note.)