Education for sustainable development plays an important role in the cognitive and social development of pupils. A wealth of studies demonstrate the correlation between environmental education (EE) projects and the future potential development of informed and active citizens with pro-environmental behaviours. All EE project have common characteristics, but usually the pupils involved in them hold the position of little explorers. It would be interesting if students could have the role of the researcher and be actively involved in all stages of a research project. The current study aims to describe a research on the accessibility of public space and to contribute to the discussion if primary school pupils could become researchers. The main conclusion of this paper, after the evaluation of the research project, is that pupils from the upper primary school classes can play an active role in a scientific research project.