The main idea of this unit is that of “open inquiry”, which means the pupils autonomously research on the guideline question “which energy source is the best?” Directing them in this process is done with the help of “bounded inquiry”, i.e. through given questions and criteria, which also adjusts focus on the experimental material at hand. Because the pupils develop their own criteria to assess renewable energies and use them to guide their research and studies, this unit satisfies every aspect of IBSE in the definition used by ESTABLISH. The teaching and learning aids present possible ideas that could be researched.