Caroline Hasler’s high-school project on the luminescence of Ba7F12CL2:Eu2+ is as impressive as it is promising: she took a kaleidoscopic jumble of measurements and hypotheses and turned them into a meaningful piece of work on a par with the experimental section of a Master’s thesis, with a view to its later expansion and publication. She was fascinated by the physical reasons for luminescence and its technological applications, and so she began to explore them in a laboratory of the Department of Physical Chemistry at the University of Geneva. At the same time, she investigated how fluorescent materials are tested for their commercial potential. “It was a highly exciting time, and produced results that were just as exciting”, says Hasler. Her experiments did not just comprise collecting information on the future optimization of the florescent material she was analyzing. She also happened upon an interesting discrepancy. “According to my measurements, the luminescence of Ba7F12CL2:Eu2+ could involve another mechanism, one different from what the theoretical model has presupposed up to now”. To be continued…