To unravel how science museums can prepare citizens for reflection on research and innovation, this study evaluates a playful exhibit prototype, Opinion Lab (OL). The OL made children and parents reflect on synthetic biology (SB), supported by conversation exercises, citizen-narratives, and futuristic scenarios. We analysed 26 OL test sessions performed in NEMO science museum Amsterdam. The prototype appeared to support participants in opinion forming, counter-argument incorporation and extrapolation. Also, reflection on deeper questions such as `what is nature?' evoked understanding for alternative viewpoints. These findings show that playful exhibits, like the OL, potentially facilitate dialogue in science museums very well.