<![CDATA[The ability to measure quantities is a fundamental component of primary mathematics education due to its relevance in both real-world applications and mathematical horizontality. However, the concept of time measurement remains one of the most challenging topics for students to grasp due to its abstract nature. Despite the recognized difficulties, there is a lack of effective instructional strategies that integrate constructivist approaches to enhance students' conceptual understanding of time. Addressing this gap, this study presents the design and implementation of a constructivist didactic sequence based on active learning within an Inquiry-Based Learning (IBL) framework. The study involved 31 pre-service teachers in their final year of training, aiming to enhance their pedagogical competence in teaching time measurement through the use of sundials. The research explores how these future educators conceptualize time and how they interpret sundials as a means to represent its passage. To evaluate their assimilation and comprehension of the topic, a phenomenographic analysis was conducted, comparing their depth of knowledge before and after the intervention. The findings indicate a significant improvement in both conceptual understanding and didactic application. The results underscore the effectiveness of sundials as instructional tools, not only for illustrating the passage of time and calendar cycles but also for highlighting the social and historical contexts associated with timekeeping. This study contributes to the field of mathematics education by providing empirical evidence supporting the integration of inquiry-based, constructivist methods in the teaching of time measurement, ultimately enhancing pre-service teachers’ instructional competencies and students’ conceptual grasp of temporal concepts.]]>
