The low-level cold I’ve been nursing for a month now finally exploded into the full unpleasantness of my usual winter illness Saturday, or else I would’ve been more active following up on my Deflategate article and my ideal gas law post. As it was, for most of the day, I could barely keep on top of clearing comments from moderation.
Anyway, a few things deserve more prominent responses than a comment at the end of a long post, so:
— I was in bed during the great Bill Belichick press conference, though I saw some mockery of it come across Twitter. While it may not have played well with the sports media, I do applaud the Patriots for doing a bit of science, here. Good for them, and the sports media can pound sand.
— Their story seems to be that right before they fill the balls, they do… something to the outside that tends to raise the pressure. It’s described as “scuffing up,” but for all I know involves a belt sander. Anyway, the balls are filled to the low end of the legal limit right after this mystery procedure, then the pressure drops as they settle down, ending up below the legal limit some time later. And cold weather will tend to enhance that.
And, you know, it might be the cold pills, but I kind of buy that. It’s mostly consistent with what we know, and would fit their organizational profile of walking right up to the edge of what’s allowed by the rules. It would suggest that they’ve been preparing balls that were technically illegal for a long time, and it’s just that this time somebody in power noticed.
— I do mostly agree with several people who have said that this would be a non-story if it didn’t involve the Patriots. That’s not quite true– if it involved the Cowboys, say, I think it would also be a huge story. But, yeah, the Patriots and their image are a big issue, here. But then, you get what you pay for. They’ve worked really hard, often right at the edge of the rules, to lift themselves up from an afterthought to one of the most prominent franchises in the sport, which is great. This sort of overdone scrutiny is the down side of that transformation, and an inescapable part of success.
It really is a pretty silly story, though, and without the physics angle, I probably would’ve just rolled my eyes and moved along.
— A couple of other tidbits from that article about the press conference are interesting, chiefly this paragraph:
In a statement Friday, the NFL confirmed reports that multiple footballs used in the first half by the Patriots fell below the range of 12.5 to 13.5 pounds per square inch. The Patriots led at halftime, 17-7. Playing the second half with footballs that were measured — both before and after the half — as conforming, the Patriots outscored the Colts, 28-0.
The “both before and after” speaks to one of the more common alternate explanations, namely that the balls getting knocked around in the course of the game would lead to some sort of pressure change. If they checked the balls at the end of the game and found pressures in the same range as after the halftime re-inflation, that would tend to indicate that there’s no significant usage effect. Which doesn’t surprise me– football is largely a game of standing around waiting for the next play to start, and they rotate balls fairly often– but it’s nice to have a bit of second-hand confirmation.
— Regarding the questions about my experiment, it looks like the pressure sensor I was using measures absolute pressure, not gauge pressure, which is why the results fit the ideal gas law so nicely. I’m not sure exactly how it does that (internal barometer? adding 14 psi to everything?); I just grabbed it off the shelf and plugged it into the computer.
There have been a lot of claims made about this being due to non-ideal-gas behavior of one sort or another, none of which I buy. The ideal gas law was originally developed in experiments in just this sort of range of pressures and temperatures– if there were significant deviations from it for pressures not all that much above atmospheric pressure and temperatures where water is a liquid, thermodynamics would be very different.
There have also been repeated calls-slash-demands for me to re-do the tests, which I won’t be doing because I have a day job (and the aforementioned nasty cold). I’ve already put off a bunch of paper grading longer than I should’ve on account of this whole business (admittedly, it isn’t hard to get me to put off grading…). I’m satisfied that I understand what’s going on, over a range of temperatures that spans those relevant to the game (data points at 20C and 1C), so I’m moving on to the next thing.
— Finally, as to rooting interests: The Conversation has a “disclosures” section, and I thought of adding a humorous note about my football fandom. I decided not to, as I didn’t know how that would be received by that audience. For the record, though, I’m a Giants fan married to a Patriots fan (yes, that’s led to some awkward moments, none worse than watching the Giants beat the Pats from the delivery room at the hospital when The Pip was born…). Some gentle snark aside, I’ve always liked Bill Belichick, back to his days helping my Giants win a couple of Super Bowls under Bill Parcells.
A week from now, if I managed to watch the game at all (not a sure thing, given two cartoon-mad kids in the house), I’ll be rooting for New England (it helps that I find the Seahawks hard to like…). That doesn’t stop me from rolling my eyes a little at their approach to NFL rules, though…
And that is probably just about enough on this whole weird story.