Purpose: Scientific inquiry is a leading methodology that promotes science process skills to acquire scientific knowledge. There is evidence that primary school teachers have difficulties introducing inquiry-based activities in their classrooms. Hence, adequate teacher instruction in inquiry methodology is important to apply inquiry-based activities in school science lessons. This work aims to analyse if pre-service teachers succeeded in developing scientific knowledge and scientific skills through the application of an inquiry laboratory activity. Design/methodology/approach: This article is presented as a case study developed in a group of 82 pre-service teachers. This research methodology involved qualitative and quantitative data. Findings: The results demonstrate that pre-service teachers could improve their scientific skills and knowledge through inquiry-based laboratory activity. Originality/value: The present study assesses not only the scientific knowledge but also if students can acquire scientific skills by doing the inquiry laboratory activity and if these skills are related to low-order cognitive skills or high-order cognitive skills.