Cheating liars or lying cheaters?

[glhs837]

Well, there's ideal, then there's real. Goodyears experts say this

"Goodyear experts explain that air pressure in a tire typically goes down 1-2 pounds for every 10 degrees of temperature change."

http://www.goodyear.com/cfmx/web/corporate/media/news/story.cfm?a_id=371

and this gent did some real world stuff

http://www.arden.org/misc/pressure.html

I could go on, and I'm not saying those others folks calculations are not accurate, what I'm saying that real world experience in air filled containers in the real world is what leads to that 1-2 psi per 10 degrees rule of thumb. And I watch my own tire pressure closely enough that I'm convinced of it's applicability. Is that what happened? Cant say, might be the Pats filled them in a room with a higher temp, knowing when the measurement would be taken so that the pressure drop would cross inside the legal boundaries at the right time...... can't say. But I can say that I think, based on real world experience, that .5 is a really low number for that pressure drop.

 

[Tilted]

Well, there's ideal, then there's real. Goodyears experts say this

"Goodyear experts explain that air pressure in a tire typically goes down 1-2 pounds for every 10 degrees of temperature change."

http://www.goodyear.com/cfmx/web/corporate/media/news/story.cfm?a_id=371

and this gent did some real world stuff

http://www.arden.org/misc/pressure.html

I could go on, and I'm not saying those others folks calculations are not accurate, what I'm saying that real world experience in air filled containers in the real world is what leads to that 1-2 psi per 10 degrees rule of thumb. And I watch my own tire pressure closely enough that I'm convinced of it's applicability. Is that what happened? Cant say, might be the Pats filled them in a room with a higher temp, knowing when the measurement would be taken so that the pressure drop would cross inside the legal boundaries at the right time...... can't say. But I can say that I think, based on real world experience, that .5 is a really low number for that pressure drop.

It may be a rule of thumb for certain kinds of things - e.g., tires. But, even to the extent it's ballpark accurate for them (and that's all it is - ballpark), it doesn't apply at all when it comes to other kinds of things - i.e., things that start at different pressures. Again, it's proportional based on the beginning pressure. At 1000 psi, the pressure will change 100 times as much for a given temperature change as the pressure will at 10 psi.

 

[Ken King]

Well, there's ideal, then there's real. Goodyears experts say this

"Goodyear experts explain that air pressure in a tire typically goes down 1-2 pounds for every 10 degrees of temperature change."

http://www.goodyear.com/cfmx/web/corporate/media/news/story.cfm?a_id=371

and this gent did some real world stuff

http://www.arden.org/misc/pressure.html

I could go on, and I'm not saying those others folks calculations are not accurate, what I'm saying that real world experience in air filled containers in the real world is what leads to that 1-2 psi per 10 degrees rule of thumb. And I watch my own tire pressure closely enough that I'm convinced of it's applicability. Is that what happened? Cant say, might be the Pats filled them in a room with a higher temp, knowing when the measurement would be taken so that the pressure drop would cross inside the legal boundaries at the right time...... can't say. But I can say that I think, based on real world experience, that .5 is a really low number for that pressure drop.

Do you run your tires at 12.5 to 13.5 PSI? I suspect your tires are X3 the pressure or more so wouldn't your change be X3 over the lower starting pressure.

Now, more importantly, did the same person, prior to the game, verify all 24 balls were in specs? Did they use the same gauge or a team supplied gauge? Was the gauge digital or mechanical?
If mechanical, was the gauge viewed at the same viewing angle? Come on, this is some serious sh!t?

 

[glhs837]

I'll note that 30 psi is much closer to 12 than to 1000 Not apply at all? I wouldn't say that. and of course, as Ken notes, there are so many other factors, the whole thing is sort of angels on the head of a pin.

 

[Ken King]

Sure. I think it's fair to say that the pressure of the balls did not, in this game, end up making the difference.

I was answering the question of why it mattered (or could have mattered), responding to the notion that both teams use the same balls - they typically don't, not in the regular offense-defense game anyway.

And I'd say, it shouldn't much matter whether the cheating (if there indeed was some) ended up being needed. That's something we (and the cheater) doesn't know until after the fact. It should be punished - whatever punishment is appropriate, if punishment is appropriate at all - the same regardless. Speaking of cheating generically, it could have made a difference (and perhaps it did in other cases when it wasn't caught), thus it needs to be punished in order to discourage it to some extent.

Oh, I know what you were answering to, I just wanted to shift the point a bit.

 

[Grumpy]

Come on, this is some serious sh!t?

exactly

 

[Tilted]

I'll note that 30 psi is much closer to 12 than to 1000 Not apply at all? I wouldn't say that. and of course, as Ken notes, there are so many other factors, the whole thing is sort of angels on the head of a pin.

The notion of a rule of thumb would still apply at lower pressures, sure. But the number - the rule of thumb amount we'd expect the pressure to change - would be quite different. At 10 psi, the rule of thumb would be more like a quarter pound per 10 degrees F. At 40 psi, it would be more like 1 psi per 10 degrees F (it still depends on the starting temperature to some degree, and that rule of thumb slightly overestimates the pressure change). So, you can have a rule of thumb for tires - it isn't particularly precise, but it's probably close enough to be helpful - but that's because most tires are in the ballpark of the same pressure. For those that aren't - e.g. for tires that might be at 10 psi or 100 psi - that rule of thumb wouldn't be any good. And, yes, we're talking about the ideal gas law, but that law is quite accurate even in the real world - so long as we're talking about reasonable pressures and temperatures, e.g. we aren't standing on the sun or inside a black hole. There are of course other issues in the real world, e.g. leakage, but I was responding specifically to the temperature change affect. There isn't much doubt on that front how much a given temperature change can affect a given pressure.

I just looked at that second piece you linked - it confirms what I'm saying, it doesn't dispute it. He's talking about tires at a significantly higher pressure than we're dealing with with the footballs. And his charts confirm that at lower pressures the temperature changes have less (absolute value) effect on pressure. It's a percentage of whatever pressure we're starting with, not a set amount regardless of the starting pressure.