Physicist Wanted: On Monday a law firm helping the National Football League investigate the New England Patriots for possible cheating brought out the big scientific guns, calling for Columbia University physicists’ help. They needed to determine the extent that the weather conditions at the American Football Conference Championship game on January 18 could have impacted a football’s internal pressure and whether it could be to blame for 11 of 12 Patriots footballs being suspiciously underinflated during their trouncing of the Indiana Colts. Apparently, nobody’s stepped up yet in an official capacity, but plenty of professional and Monday-morning scientists have taken to the Web to offer their own analyses.
The basic facts, of which I’ve been blissfully and willfully unaware until now: During the AFC championship game between the Patriots and the Colts—that determined which team would go on to the Super Bowl, and which the Pats won by a large margin, 45–7—officials found that almost all of the Patriots’ footballs were around two pounds per square inch below the regulation pressure range of 12.5 to 13.5 psi, giving them an unfair advantage. (Side Note: Each team’s quarterback gets to select his own footballs before the game, and different players have different preferences. The pregame inspection process is shown here.)
The balls somehow dropped in pressure between being checked by the referees and halftime—was it foul play? A who’s who of the hands footballs pass through before and during a game creates an intriguing list of suspects (see this time line of events), but as those avenues of speculation have tired, the curious public has begun to grapple with the science.
First of all, the terminology. People have been fumbling over understanding “pounds” taken off the balls versus “pounds per inch of pressure”—the actual weight difference would have been more like the weight of a dollar bill, according to ESPN’s Sport Science video. Many, including science popularizer Neil deGrasse Tyson, misunderstood the pressure measurement as one of absolute pressure (as if the ball was in a vacuum) rather than gauge pressure, which takes atmospheric pressure into account.
But once that was sorted out, the experiments began. According to chemistry’s ideal gas law, reducing the temperature of a gaseous system in a confined space also reduces the pressure of the system—Could nature itself then be the culprit? The basic physics is covered very well in this video by Ainissa Ramirez, materials scientist and co-author of Newton’s Football, for Time magazine—plus, she discusses whether a deflated ball would have offered an advantage to start with.

Ramirez notes that a deflated ball benefits many players: it’s easier for a quarterback to grip, a receiver to catch, a runner to carry as well as easier to kick. (This Houston Chronicle article describes the lengths players would go—kickers especially—to tamper their way to the perfect ball, along with the efforts the NFL takes to curb them.) On the other hand, a deflated ball also doesn’t fly as far. (ESPN’s video suggests, however, that there’d be very little difference in game play—the rainy field would have had far more of an effect.)
Chad Orzel at The Conversation, a physicist at Union College, stuffed footballs in his freezer and found that after a cold night the footballs’ pressure had dropped by two pounds per square inch, just like the Patriots’ balls. Of course, that was from a temperature drop of 78 degrees Fahrenheit. A blogger named Hondo calculated that the temperature on the playing field would have had to make it down to 31 degrees F to cause the change—much colder than it actually was during the game. Even Bill Nye the Science Guy deduced on video that the temperature alone wouldn’t have been enough, although his contribution was mostly dedicated to ranting about climate change while waiting for footballs to chill.
There’s always a chance more variables—wear and tear, rain, friction—could have kept the pressure high in the first measurement or lowered it by the second. And even the most basic details could be overturned—What if the other balls weren’t as deflated as the first one?—rendering empirical analysis useless. For now the physics has spoken—and we’re not much better off. But a national fixation on possible cheating in sports morphing into one on pounds per square inch, gauge pressure and the ideal gas law? That I can get behind.