The primary school science fair was an event held aboard the USS Enterprise-D. Students from the ship's primary school submitted projects which were judged, with three winners chosen.
In 2368, the winners were Jay Gordon Graas (for a study of the swarming moth of Gonal IV), Paterson Supra (for a study of radishes), and Marissa Flores (for an unspecified project). Captain Jean-Luc Picard was to give the three children a tour of several areas on the Enterprise-D including hydroponics and astrophysics laboratories, but the tour was interrupted when the Enterprise-D hit a series of quantum filaments. After the crisis was resolved, Captain Picard promised to resume the tour, this time starting with the battle bridge. (TNG: "Disaster")
As the three winners were of different ages, it is possible that they were each the winner in their particular grade or age group.