The major purpose of the present study was to investigate how young students understand scientific inquiry when they are involved in activities performed in a real science research context, i.e. under a scientific research project, with scientists and in a marine research laboratory. The novelty of this study is the engagement of very young students (9 or 10 years old) in experiments, contributing to fill the gap of studies in real contexts in early school years. Additionally, we also aimed at making this inquiry-based activity accessible to a large amount of students, which is important to detect their most common difficulties.