“By the ideal gas law, a football inflated to 12.5 at 72 degrees and cooled to 51 degrees [the temperature on the field during the first half] will have a final pressure of 11.43 psi, thus a loss of 1.16 psi … A second factor, the expansion of a football as it gets wet, also leads to a drop in psi. This factor contributes another 0.7 psi in pressure drop … Plain English ultimate conclusion: It would be reasonable to expect, based on both experimental results and ideal gas law calculations, for a pressure drop in excess of 1.5 psi to have occurred within the Patriots footballs in the first half, based on the known game-time conditions and the observation that the footballs were inflated to 12.5 relative psi at room temperature.
“[But] what about the Colts footballs? We don’t know their initial pressure, but if we assume that they were the maximum legal pressure of 13.5 psi relative pressure, we can calculate the expected pressure drop. Thus the Colts footballs should have been a final pressure of 12.3 psi. The legal lower limit is 12.5 psi. The Colts footballs should have been illegal by 0.2 psi. Question: Would a referee call a reading of 12.3 rather than 12.5 to be clearly out of specifications and illegal? Maybe yes, maybe no. It certainly depends on both the accuracy and precision of the pressure gauge.
“Final conclusion: It is not unreasonable at all to assume that the Patriots balls would fail the inspection and the Colts balls would (barely) pass, based upon logical assumptions of inflation levels, inflation temperatures in concert with the issues of temperature-related gas expansion, the expansion properties of a leather football as it becomes water-soaked, and the human-element.”
So I called Bannister Monday, and we discussed it. I said the assumption is the Colts footballs were at the higher pressure level, and that’s perhaps why they didn’t flunk the halftime pressure test; but there’s no proof of that. But if the Colts did deliver footballs to the officials at 13.5 PSI, then clearly there’s a chance the pressure level would have hovered around 12.5 PSI, and it’s possible the differing results have to do with where each football that was tested was set before the game.
In other words, there’s much we don’t know.
“There’s a lot of missing pieces in this story,” Bannister said.
In this case, truer words have never been spoken. Wells has much to discover. I just hope he gets to discover everything that’s important here.
