Children's role in the design of new technology has been widely investigated. Recently, the research focus has shifted, from the technology they help create, towards what children gain by participating in design workshops. This paper intercepts this line of research. It reports on a design workshop with 27 children, aged from 11 to 14 years old, ideating, programming and prototyping smart objects for their town park. Data were gathered in relation to children's beliefs, before and after the workshop, and in relation to their understanding of design, after the workshop. The analysis of the gathered data suggests that the workshop positively affected children's beliefs and understanding of design, giving indications for future work concerning...