Deflate-Gate and Physics

For all you adults out there... Charles' Law describes the relationship between the absolute temperature of a gas and the absolute pressure.

To find the absolute temperature you need to convert Fahrenheit to Rankine degrees. To do this, add 460 to F to get K. So in Bill Belichick's TV press conference he indicated the locker room temperature was 75 degrees F (75 + 460 = 535 K) and the field temperature was 50 degrees F (50 + 460 = 510 K).

Assume Tom Brady's footballs were all inflated to the maximum allowable, 13.5 psi gauge. We need to convert gauge pressure to absolute pressure. At sea level we add the atmospheric pressure (14.7 psia) to the gauge pressure (13.5 psi), we discover the initial absolute pressure was 13.5 + 14.7 = 28.2 psia).

Multiplying the initial absolute pressure at 75 F (28.2 pia) by the ratio of absolute temperatures (510/535 = 0.95327) we find the absolute pressure on the field is (28.2 x 0.95327 = 26.88 psia). Converting absolute pressure back to gauge pressure we need to subtract the atmospheric pressure of 14.7 psia. The field gauge pressure then becomes (26.88 -14.7 = 12.18 psig).

So, with no cheating, simply taking the ball outside into the 50 degree air and letting the ball reach ambient temperature will cause the internal pressure to drop below the minimum allowable pressure of 12.5 psig. So by that standard, everyone "cheats", especially the league referees. If the Patriots were "cheating' so were the Colts.

But this is all on the QT! Don't tell the hysterical media! And certainly don’t ask how low the pressure inside the ball got during the Ice Bowl Game!

For all you adults out there... Charles' Law describes the relationship between the absolute temperature of a gas and the absolute pressure.

To find the absolute temperature you need to convert Fahrenheit to Rankine degrees. To do this, add 460 to F to get K. So in Bill Belichick's TV press conference he indicated the locker room temperature was 75 degrees F (75 + 460 = 535 K) and the field temperature was 50 degrees F (50 + 460 = 510 K).

Assume Tom Brady's footballs were all inflated to the maximum allowable, 13.5 psi gauge. We need to convert gauge pressure to absolute pressure. At sea level we add the atmospheric pressure (14.7 psia) to the gauge pressure (13.5 psi), we discover the initial absolute pressure was 13.5 + 14.7 = 28.2 psia).

Multiplying the initial absolute pressure at 75 F (28.2 pia) by the ratio of absolute temperatures (510/535 = 0.95327) we find the absolute pressure on the field is (28.2 x 0.95327 = 26.88 psia). Converting absolute pressure back to gauge pressure we need to subtract the atmospheric pressure of 14.7 psia. The field gauge pressure then becomes (26.88 -14.7 = 12.18 psig).

So, with no cheating, simply taking the ball outside into the 50 degree air and letting the ball reach ambient temperature will cause the internal pressure to drop below the minimum allowable pressure of 12.5 psig. So by that standard, everyone "cheats", especially the league referees. If the Patriots were "cheating' so were the Colts.

But this is all on the QT! Don't tell the hysterical media! And certainly don’t ask how low the pressure inside the ball got during the Ice Bowl Game!