How to reduce the amount of air in a football without letting any air out

Watts Up with That? ^ | January 28, 2015 | By Alec Rawls

[Brad from Tennessee]

Just fill the ball with warm humid indoor air, then when it temperature-equalizes with the 25°F cooler outdoor air on your AFC Championship playing field some of the water vapor in the ball will condense into water, leaving less air in the ball, solving the great mystery: how did the footballs used by the Championship winning New England Patriots show 12.5 psi of inflation pressure in the official pre-game check but only 10.5 psi when checked at halftime?

There is also a decrease in pressure due to the cooling of the molecules that remain gaseous. Those air molecules are not zipping around as fast as they were so they exert less outward pressure on the ball. But according to the ideal gas law, if there were no reduction in the number of gas molecules in the balls it would have taken a large drop in temperature, about 40°F, to cause the observed drop in air pressure. So says Boston College professor Martin Schmaltz:

"In order for a ball to register a 10.5 PSI in a 50 degree environment [the temperature on the field at halftime] but register a 12.5 PSI in the testing environment, the ball would have to have been inflated, stored, and/or tested in a 91 degree environment."

[Red Badger]

Yep! They would have to find another way to, uh, ‘bend the rules’...............

[Starwolf]

Dry nitrogen simple means the tires change more uniformly. The gas will still expand/contract with temperature. (basic physics)

[cdcdawg]

Probably so. I still can’t see how a deflated ball is easier to throw. Catch, maybe, but not throw. Nice username.

[Mad Dawgg]

"God, you’re a genius... only why only the Patriot balls were deflated...”Old shoe cleats breath?”"

Question One: Were the other balls checked?

Question Two: What pressure were the other teams Balls initially inflated to?

Question three: If the other teams balls were inflated to say the maximum did they lose pressure but still stay within the acceptable range?

[Tallguy]

“Doesn’t the pump heat up as you inflate the balls to begin with? So you could be dumping warmer than room temperature air into the balls before sending them out in the cold.”

True but a negligible effect since the volume of air being pumped into a football is small. It’s the difference between filling a bicycle tire and a car tire. The bike tire reaches rated pressure very quickly. The heat content of that volume of air is less even if the temperatures are the same.

[Blood of Tyrants]

The pressure at 40 deg will still be lower than at 75 degrees.

[TNoldman]

Football ping

[cripplecreek]

Seeking “an edge” is a time honored tradition in NASCAR.

Darrell Waltrip tells a story about going around Talladega and seeing someone passing and the rear spoiler was laying flat. He thought about pointing it out to the officials but decided to threaten that team’s crew chief to let him in on the secret instead.

Turned out that the team had machined some tiny shock absorbers to look like the struts that are supposed to stiffen the rear spoiler. The faster the car went, the flatter the rear spoiler would get.

[jyro]

the balls were wet also

[Fresh Wind]

Dry nitrogen and the NFL providing the balls would kill the issue dead.

Regardless of how this shakes out, it's a pretty safe bet that there will be some rule changes for next season. One thing you won't see again is the teams having control of the balls after they have been checked by the officials.

[jyro]

it also depends of the humidity of the air they were filled with, as someone mentioned, filled with nitrogen it has no humidity.

[E. Pluribus Unum]

If only there had been two more PSI in their footballs the Colts would have won!

</sarcasm>

[Steely Tom]

Thanks for the correction about gage pressure.

[smaug6]

I read the rule after this started. Have you? I am accustomed to reading technical specs and looking for unsaid or poorly stated specs. I am astounded at how poorly rule 2 reads in regards to pressure. First the units are incorrect. Second it only says the balls are to supplied at that pressure to be tested. That they be maintained at that pressure is left unsaid. Where is the game requirement for pressure. Nowhere in my mind. The process for out of spec balls was followed. I see no problem with the Pats actions if they simply deflated them. It isn’t specifically prohibited.

[SunkenCiv]

Any Big Bang Theory fans?

Sulfur Hexafluoride - Deep Voice Gas - YouTube
http://www.youtube.com/watch%3Fv%3Du19QfJWI1oQ

My voice after inhaling Sulfur Hexafluoride - YouTube
http://www.youtube.com/watch%3Fv%3DvcVMjGRzDz8

How to get a deeper voice with Sulphur Hexafluoride - YouTube
http://www.youtube.com/watch%3Fv%3DRaKDLWsWfSM

[The Cajun]

We would use sulfur hex as an insulating gas for our particle accelerator tools, also great for freaking the heck out of the secretaries when they would come in the electronic repair shop, LOL!

Their eyes would get as big as saucers before they caught on, we would sound like "Ironman".

[Osage Orange]

Teams have their own footballs for games...........

[woofie]

I knew it ....global warming

[Billthedrill]

That or the Tea Party. You can’t trust those guys from Boston.

[FewsOrange]

I believe the official marked them without ever testing them before the game. It actually seems to be the most logical solution.

Yep. Lifted them up, gave a quick visual inspection and said that's OK.