The activities presented in this paper, which are addressed to elementary school, are focused on the pioneering work of the Portuguese King Carlos I in oceanography and involve the exploration of the exhibits belonging to two different science museums, the Aquarium Vasco da Gama and the Maritime Museum. Students were asked to study fish adaptations to deep sea, through the exploration of a fictional story, based on historical data and based on the work of the King that served as a guiding script for all the subsequent tasks. In both museums, students had access to: historical collections of organisms, oceanographic biological sampling instruments, fish gears and ships. They could also observe the characteristics and adaptations of diverse fish species characteristic of deep sea. The present study aimed to analyse the impact of these activities on students' scientific knowledge, on their understanding of the nature of science and on the development of transversal skills. All students considered the project very popular. The results obtained suggest that the activity promoted not only the understanding of scientific concepts, but also stimulated the development of knowledge about science itself and the construction of scientific knowledge, stressing the relevance of creating activities informed by the history of science. As a final remark we suggest that the partnership between elementary schools and museums should be seen as an educational project, in which the teacher has to assume a key mediating role between the school and the museums.