Lately these days I have been reminiscing about what science fairs were like when I was in school. It worked like this: Each project was associated with up to three class subjects, and the participants received extra marks on their grades in those. So kids gathered around and surveyed what subjects they most desperately needed extra marks on. "Ok, so we need a project about Mathematics, Biology ... and Grammar." Or, say, "Chemistry, Geography, and English". Or, I don't know, "Physics, Informatics, and the Arts."
Needless to say, this process also yielded a list of the three classes the group collectively liked the least and cared the least about. But oh, not everybody was desperately looking for grades. Groups often managed to recruit a geek or two, who did the science fair thing for the pleasure of it, and who usually wanted to do something very scientific and mathy. And sometimes nerds would gather together in groups that really didn't care about grades, and make projects about, oh, the Vampire: the Masquerade role playing game.
(No, I never participated in any of this. I was (?) lazy, didn't work well in groups, and had a keen sense of pointless.)
Most of the projects proposed an unfeasible challenge: they had to coordinate topics that were very difficult to associate in themselves, and which, except for the occasional nerd who knew the science part, they didn't really like or know about. So most projects covered one or two of the classes on the list moderately well, and the remainder had to be weaseled through: "Ok, this is an interesting project, but what the Mercosur trade agreement has to do with Chemistry exactly?" "Ok, I see the Physics and the Informatics, but where is the Art?" The half-arsed, absurd explanations were the best part of the whole event, and it was a good idea to follow some of the teachers around just to hear them.
But then again, teachers were very liberal and condescending with the explanations. They didn't take these projects seriously - who did? - and wouldn't deny the kids their one or two extra marks for the effort. And the students of course caught on to this real quick, and the weaseling became de rigueur. And that's what a "Science Fair" scenario means to me: a place you don't even fake it that you are faking it that your project has anything to do with Geography, Chemistry, or Art.