Info needed to answer Pressure / Temperature questions.

I just started a list of the info that will be required to answer all the various technical questions related to temperature & pressure.
Hopefully, the Wells investigation will gather ALL of this info.

This list specifically excludes any politics, any who done what, who said what to whom.
I'm only interested in the tech questions.

I'm posting it to see if others can come up with some more variables that I missed.
After a couple of days, I'll send the list to Wells & to the Pats organization.
No idea what good it'll do. It might delay the report another 3 months..!
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Pats balls info needed

1. Location that the Pats balls were checked at half time? On field? In locker room? Both?
2. Approximate time between Pats balls taken into locker room & pressure checked.
3. Type of pressure gage used. Spring & plunger? Bourdon Tube? Electronic?
4. Last calibration of pressure gage.
5. Pressure of EACH Pats ball at start of half time, to best recollection.
6. Clarify “11 of 12 balls” comment. Where was 12th ball? On Colts’ sideline?
7. Pressure to which the referees re-inflated the Pats balls prior to 2nd half.
8. We presume that the Pats ball that the Colts intercepted was the trigger for the referees' investigation at half time. Is this true?
9. What is the best estimate of the number of times that ball was pressure checked by the Colts staff, prior to being shown to the referees?

Colts balls info needed:

1. Colts balls location & approximate temperature for 3 hours before referee’s pre-game inspection.
2. Pressure that Andrew Luck sets his footballs.
3. Did the referees measure the Colts’ balls on the field at half time? In the locker room?
4. Pressure, to the best recollection, of all of Colts balls on field.

Additions encouraged & welcome...

SlowGettingUp reminded me of this one:

An early report said that "11 of the 12 balls were 2 pounds (really psi) under". But it didn't say, "2 psi under WHAT". Can you claify? 2 psi under the nominal pressure of 13.0 psig? Or 2 psi under the minimum of 12.5 psig?

I want to post this here too.

VectorPrime said:

If the Patriots had 12 balls in use obviously all 12 would be affected by the weather but wouldn't the degree vary depending on how much they were used? Some of the balls probably just sat in the bag for the entire half. Wouldn't it make sense then that those balls would have then not lost as much internal pressure, supporting Florio's report about the varying PSI levels?

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It's UNKNOWN how much pressure a ball loses from use. My guess insignificant realitive to the issue under discussion. In other words it does not matter. Temperature over time does matter.

PatsWickedPissah said:

It's UNKNOWN how much pressure a ball loses from use. My guess insignificant realitive to the issue under discussion. In other words it does not matter. Temperature over time does matter.

Click to expand...

Agreed, with one caveat: as long as the ball doesn't spring a leak during the game.

One (out of 4) of the balls I tested sprung a leak, just from my moving it (repeatedly, over a period of 70 minutes) from a test bench to a cold water bath to a refrigerator. Nobody jumping on it, spiking it, etc.

I suspect that this was a manufacturing defect, that some percent of the balls (less than 25%, or Wilson would be out of business) do this with "normal" use.

But I also believe that the use & abuse the teams put them thru prior to selection as "one of the 12 chosen as game balls" will weed out the vast majority of these flawed balls.

But should a bad ball make it thru the selection process & pop a leak during a game, it will likely deflate pretty damn quickly. Air is pretty damn slippery.

The leak I saw gave a continuous stream of bubbles when immersed in water (which is the only reason that I noticed it). I suspect - but did not measure! - that it would have been down to 4 to 8 psi within 30 minutes or so.

So I'd not be surprised if one, perhaps even 2, of any group of balls were serious "outliers". But they wouldn't be just 0.5 to 1 psi lower than the others. They'd be down significantly more than this, depending on the length of time between popping the leak & being checked.

But, even as I write this, I realize that this has GOT to be just like car or bicycle tires, which show a whole spectrum (slow to fast) of leak rates.

IF (& this is a big "if", that I don't believe occurred in the Pats/Indy case, at the moment) one ball tested at a significantly lower pressure than all the rest, this strikes me as the highest probability for the cause.

I think another factor that effected heavily used balls vs balls left in the bag was water. Water on the surface of an object effects it's temperature and the rate of temperature change from say, the indoor temperature they filled and originally checked the balls to the temperature they attained when checked at halftime. Water may effect volume too, if the leather covering the ball changes when it's wet.

And of course temperature has a strong relationship to pressure.

It was pouring that night. Probably the hardest rain during a Pats game the whole year. And I would presume balls that were heavily used came in contact with more rain. Therefore were cooler. Probably even cooler than the ambient air once you factor in the effect of evaporation and the fact that rain comes from a higher altitude where it is colder than on the field. Balls that remained in the bag most of the night=less contact with rain.
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RE Question #6: I don't have a citation for this. But I think the "12th ball" was thrown into the stands in the first half by Blount. Therefore wasn't available to be part of the data set.

tom.kordis said:

I just started a list of the info that will be required to answer all the various technical questions related to temperature & pressure.
Hopefully, the Wells investigation will gather ALL of this info.

This list specifically excludes any politics, any who done what, who said what to whom.
I'm only interested in the tech questions.

I'm posting it to see if others can come up with some more variables that I missed.
After a couple of days, I'll send the list to Wells & to the Pats organization.
No idea what good it'll do. It might delay the report another 3 months..!
__

Pats balls info needed

1. Location that the Pats balls were checked at half time? On field? In locker room? Both?
2. Approximate time between Pats balls taken into locker room & pressure checked.
3. Type of pressure gage used. Spring & plunger? Bourdon Tube? Electronic?
4. Last calibration of pressure gage.
5. ...
   
   Additions encouraged & welcome...

Click to expand...

Whether the valve was cleaned prior to gauging. Dirt in the valve can let air out when you measure the pressure.

Why blame Tom when we all know Jack Frost did it!!

Gisele said:

Why blame Tom when we all know Jack Frost did it!!

Click to expand...

Since "Jack Frost" is just another of Mother Nature's pseudonyms, your (I'm guessing, snarky & sarcastic) statement happens to be correct.

"Even a blind pig ..."

One factor that none of the calculations I've seen seem to account for is the temperature rise that occurs when air is added to a football. Air compression would raise the temperature inside a football above ambient room temperature inside a locker room and increase the differential between initial conditions and the eventual outdoor equilibrium temperature. Of course, this assumes that officials added air to any footballs pre-game to bring them up to standards. But if they added air to some and left some alone, this would also account for some of the variability at halftime, assuming again that the refs maintained tight specs in the initial inflation pressure.

Letting air out to bring them to a set standard would similarly lower temps inside the ball and decrease the differential.

All in all, I see no evidence in the Wells report of unnatural decreases in pressure. In light of that, the text messages are meaningless.