I dunno. It all seems pretty reasonable to me. She did something that was potentially dangerous. I mean, by high school you should know, or at least suspect, that making a bomb for your science project isn't a good idea, even if it isn't meant to do much more than smoke and fizzle. At least consult with a teacher before doing that! But it seems she didn't intend any harm and no one was hurt, so letting her back in school is proper, though she maybe ought to have some kind of extra punishment like detention on top of the suspension.