Abstract
In this article, we analyze a case study of an Italian secondary school mathematics teacher engaged in the European project STEAM-Connect. The teacher designed a STEAM activity with colleagues of different disciplines, involved in the project by researchers. The aim of this qualitative study is to elaborate on the evolution of the investigated collaborative design work from a multidisciplinary to an interdisciplinary and, in the end, towards a transdisciplinary approach. The collected data come from two interviews with the mathematics teacher and the activity described through a design template shared within the “STEAM-Connect” project. In the concluding discussion we outline the several levels of connection, horizontal and vertical, national and international, between the teachers and the researchers involved in the project. Such connections triggered and sustained the evolution of the design of the STEAM activity towards a transdisciplinary approach, that is based on a real-world problem that can be approached from the perspective of different disciplines.