MISQUAH — The annual Prairie View Middle School science fair concluded Wednesday with first prize going, for the forty-fifth consecutive year, to a baking-soda volcano — a result so reliable it has acquired the force of natural law and the resignation of a weather pattern.

This year’s winning entry, built by seventh-grader Jaxon Lindholm, stood nearly three feet tall and erupted twice on schedule and once unscheduled, during judging, onto the table skirt. “He committed to it,” said fair coordinator Lois Hagen, who teaches eighth-grade math and has run the fair since 2007. “It’s a good volcano. It is a better volcano than last year’s volcano. I have judged a great many volcanoes and I know one when I see one.”

Second place went to a project titled “Why Loons Are Heavier Than Other Birds,” a genuine study of bone density by sixth-grader Greta Solberg, who weighed, measured, and compared bird bones she had cataloged herself and presented her findings on a tri-fold board several parents described, in the parking lot afterward and not quietly, as “the one that was actually science.” Solberg, for her part, said she had “expected the volcano to win, because the volcano always wins,” and had entered anyway “because the bones were interesting and somebody should know about them.”

The outcome revived a complaint nearly as old as the fair itself — that the judging “rewards spectacle over substance” — a grievance that, by the Pilot-Independent’s reading of its own back issues, has followed all but one of the fair’s forty-five volcano victories. Mrs. Hagen said she was aware of the criticism and unmoved by it. “Every year somebody’s mother tells me the volcano shouldn’t have won,” she said. “And every year the volcano is the thing the kids are still talking about at lunch in October. You weigh that how you want. I’ve weighed it.” The winning volcano erupted a final, valedictory time at the close of judging; the gymnasium, staff reported, smelled faintly of vinegar through Friday.