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Author Topic:   Deflation-gate
Percy
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Posts: 22391
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


Message 1 of 466 (748151)
01-23-2015 9:55 AM


The New England Patriots are the local NFL football team here, and they're currently in the middle of a controversy. It is charged that they cheated by reducing the pressure in footballs to make them easier to grip, throw and catch in the cool, rainy weather of Gillette Stadium this past Sunday night. The NFL reports that the footballs the Patriots used were 2 psi lower in pressure during the game than when they were checked a couple hours before kickoff.
Something you'll see occasionally mentioned in news articles about the controversy is the pressure drop that occurs with decreasing temperature, but I haven't seen any of the mainstream commentators acknowledge this fact. The Patriots, and especially Bill Belichick (coach) and Tom Brady (quarterback), are being castigated in the sports press without any mention of the possibility that no breaking of the rules took place.
If the footballs were inflated indoors, then they were inflated at a temperature of somewhere around 70 degrees to a pressure of 12.5 psi. The temperature on the football field was 45 degrees, so the pressure in the footballs should have dropped around a couple of psi once the game began, which is just what the NFL reported. In this case no one deflated the footballs, but it seems surprising that the refs aren't aware that such pressure drops happen in the cold.
Of course, if the footballs were inflated outdoors then the pressure drop has no natural explanation and some person or persons must be responsible.
--Percy
Edited by Percy, : Grammar.
Edited by Percy, : "pressure drop that occurs with decreasing pressure" => "pressure drop that occurs with decreasing temperature"

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 Message 2 by jar, posted 01-23-2015 10:00 AM Percy has replied

  
Percy
Member
Posts: 22391
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


Message 3 of 466 (748169)
01-23-2015 10:47 AM
Reply to: Message 2 by jar
01-23-2015 10:00 AM


jar writes:
Were the footballs used by the other team also checked?
No article I've read has mentioned whether the Colts' footballs were checked, but that doesn't mean they weren't. If they had been inflated indoors, then they would also been below the minimum of 12.5 psi specified in the rules.
Since beginning this thread I read a summary of the procedures for checking footballs before game time, and the referees check the pressure in the footballs indoors a couple hours before the game. The article didn't say whether the footballs are originally inflated indoors or outdoors.
--Percy

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 Message 2 by jar, posted 01-23-2015 10:00 AM jar has replied

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Percy
Member
Posts: 22391
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


Message 6 of 466 (748185)
01-23-2015 11:47 AM
Reply to: Message 5 by Tempe 12ft Chicken
01-23-2015 11:05 AM


Re: Colts' footballs were not under-inflated
Yeah, I read that article a couple days ago. That information doesn't come from the NFL, it's comes from a radio station in Kansas city, and it's from at least a couple days ago anyway. Here's the full paragraph:
ESPN Sports Radio 810 in Kansas City reported that the Patriots' footballs were tested at the half, reinflated at that time when they were found to be low, then put back in play for the second half, and then tested again after the game. The report did not reveal the results of the test following the game. All of the balls the Colts used met standards, according to the report.
This doesn't say the Colts balls were retested at the half, just that they met the standards. Did the article really mean to say that they met the standards at the half? Maybe. Who knows. But I do know that you can't defeat physics. If the Colts balls were inflated indoors to the maximum, 13.5 psi, then once on the field for more than a half hour they would have tested at less than the minimum 12.5 psi.
The article also contains contradictory information. The article reports Sports Radio 810 saying that the balls were reinflated and put back in the game for the second half, but the same article cites another radio station, WEEI out of Boston, saying the backup footballs were used:
Meanwhile, a source told WEEI.com that the Patriots used 12 backup balls for the second half against the Colts after issues were found with most of the originals. Patriots spokesman Stacey James confirmed that the team had 24 balls total available, WEEI reported.
I'm waiting for the NFL report, but they seem to be taking their time.
--Percy

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Percy
Member
Posts: 22391
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


Message 8 of 466 (748230)
01-23-2015 5:51 PM


Experimental Results
I took one football (no, it wasn't an official NFL football) and in my garage where it is 30 degrees I inflated it to 11 psi.
I then brought it inside where it is 74 degrees for 1/2 hour and checked the pressure again. It was 13 psi.
I then returned the football to the garage, left it there for 1/2 hour and checked the pressure again. It had returned to 11 psi.
No football inflated to 12.5 psi at a temperature of 70 degrees will conform to NFL rules when brought onto a field at 45 degrees.
--Percy
Edited by Percy, : Add last sentence.

  
Percy
Member
Posts: 22391
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


Message 13 of 466 (748358)
01-25-2015 9:19 AM


Science Begins Receiving Mainstream Attention
New England Patriots coach Bill Bellichick yesterday revealed that he had simulated the football inflation procedures that were followed before last Sunday's game and discovered what those of a more scientific bent already knew, that temperature can affect the measured pressure in footballs, so now the mainstream media is aware that it is possible (not proven) that no one deliberately reduced the pressure in the footballs.
Another factor Bellichick discovered is that the handling of the footballs when they are roughed up to make the surface easier to grip (something teams are permitted to do under the rules) also heats them up, increasing the pressure in them. A football at 12.5 psi would probably rise to 13.5-14.5 psi after having a big, beefy guy handle it roughly for five minutes, so air would have to be let out to return it to 12.5 psi. But a half hour later the football would have returned to room temperature and would now measure significantly below 12.5 psi. I should add, though, that the footballs are apparently inflated by the referees, not by the respective staffs of the football teams.
But I think there is one other factor that might affect measured pressure. Isn't the pressure measured by pressure gauges relative to prevailing atmospheric pressure? If atmospheric pressure increases then a lower pressure will be measured in the footballs, right? So if atmospheric pressure can range between 13 and 15 psi, then a fluctuation of a half pound per square inch in the time between inflating the balls and halftime (over four hours) is a reasonable possibility.
Another variable is the air pressure in the room where the footballs were inflated. Does Gillette Stadium have a forced air system for heating/cooling? If so, does that room have a heating vent, a return vent, or both?
Bellichick said the referees inflate the footballs to team-requested pressures in a "controlled environment". I'm not sure what he meant by a "controlled environment". He might have meant that it was done indoors as opposed to outdoors, or he might have meant a special room with tightly controlled temperature and pressure, though that seems unlikely given that the NFL seems completely unaware (until now) that temperature and pressure can affect the measured pressure in a football. Was the room where the Patriots footballs were inflated next to the boiler room or was it a normal temperature?
And where were the footballs stored before being delivered to the referees for checking and pressurizing? Is the equipment room some overly warm room maybe next to the room with all the washers and dryers? If you take footballs heated up to 80 or 90 degrees and take a minute to bring them to the referees who immediately pressurize them to 12.5 psi, then the air in the footballs will still be warm. When the footballs cool to room temperature they will already be underinflated, and when brought outside will cool further and become still further underinflated.
There's an additional mystery in that one of the twelve footballs was at a higher pressure than the rest. It was still below the range, but not as much. What might have caused that? I can imagine a scenario. The warm footballs were brought to the referees who immediately began inflating them, but after completing eleven of them were interrupted. After a ten minute conversation they inflated the last football, which was now cooler.
Reports say the pressure in the Colts footballs was also checked and that they measured within the normal range, but this must be considered as much a mystery as the Patriots underinflated footballs. A football inflated to the upper limit of the range, 13.5 psi, at 70 degrees would very likely drop below 12.5 psi when cooled to 45 degrees. If the Colts footballs did actually measure within the range then it must have been just barely at or above 12.5 psi.
The opposite problem of overinflation occurs when you play in the south, especially early in the season. A football inflated to 12.5 psi at 70 degrees will increase in pressure to around 14 psi when heated to 95 degrees, something that is not at all uncommon when the Patriots play in Miami in September. And of course the pressure in a football originally inflated to 13.5 psi at 70 degrees would increase to 15 psi during the game, which is way, way outside the range.
Poor Goodell. It hasn't been a good year for him what with controversies about concussions and Ray Rice and so forth. More egg on the face now seems possible as the NFL again shows itself clueness by tightly regulating the pressure in their footballs while apparently having no idea of the effects of temperature and pressure, conditions that are completely outside their control in an outdoor stadium.
Unlike Goodell Bill Bellichick cannot be pitied. He has a well deserved reputation within the league for being an evil genius who will ruthlessly seek out any advantage. He was actually caught stealing New York Jets signals back in 2007. It is completely expected that everyone would think the worst when inexplicably deflated footballs are discovered.
--Percy

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 Message 15 by NoNukes, posted 01-25-2015 9:44 PM Percy has replied

  
Percy
Member
Posts: 22391
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


Message 14 of 466 (748422)
01-25-2015 8:51 PM


Science Takes the Stage
The national media seems to have become a bit more muted now that articles like these are coming out:
What still puzzles me is how the NFL couldn't know that temperature affects ball pressure. I know that for the most part these are sports guys, not science guys, but they do have some technical experts on staff. What should have happened is that when the Colts player complained to the ref the that ball felt underinflated, the ref, having been briefed about this issue by the home office, would have replied, "Of course it does, it's cold out. Now stop bothering me."
Other testing indicates it's really, really difficult to detect a 2 psi difference in ball pressure just by handling the ball, and that's with balls at the same temperature. Drop the temperature of the ball 30 degrees and the leather is going to be stiffer, making it even more difficult to tell the difference in pressure. Why the Colts player thought the ball was underinflated is yet another mystery.
And there's still the mystery of why the Colts balls tested out okay at halftime. Using the more accurate calculations that have recently become available, if the Colts balls were inflated to 13.5 psi at a temperature of 75 degrees before the game, then by halftime outdoors they should have measured 11.7 psi. The only way they could have measured 12.5 psi or above is if they had originally been overinflated.
Interesting fact: It's against NFL rules to inflate a football with helium. It must be inflated with air. This is known as the Ray Guy rule. It was instituted after someone complained that Ray Guy's punts had an unnaturally long hang time and that the football must be filled with helium. It wasn't (they apparently sent it to a lab and had the air in the football tested), but the rule was added nonetheless.
--Percy

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 Message 16 by NoNukes, posted 01-25-2015 10:09 PM Percy has replied

  
Percy
Member
Posts: 22391
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


Message 17 of 466 (748449)
01-26-2015 7:46 AM
Reply to: Message 15 by NoNukes
01-25-2015 9:44 PM


Re: Science Begins Receiving Mainstream Attention
Gee, thanks for reading that message. I started out just to give a short update on Bellichick's press conference and lost control.
In any event, an atmospheric (barometric) excursion of more than 1/4 psi or so would be extremely unlikely. So I think only the temperature explanations are worth considering.
That's what I thought, too, that atmospheric changes were unlikely to have played a role, but after I wrote that message I came across an article that not only mentioned this possibility (see the first article cited in my Message 14), but also reported how someone had actually checked the local barometric pressure 2 hours before game time and at halftime and discovered that it had dropped about .1 psi. This would have caused the footballs' pressure to measure greater than the original inflation pressure by .1 psi.
And say the room where the footballs were originally inflated had an air outlet and no return vent. This would increase the air pressure in the room and cause the football to measure at a higher pressure on the field. Or say the room had no air outlet and only a return vent (I know, doesn't make sense, but walls are moved easily, duct work not so much). This would decrease the air pressure in the room and cause the football to measure at a lower pressure on the field.
When would this letting air out have legally happened?
Early reports claimed teams inflated their own balls, but it turns out they turn the balls over to the refs and tell them what pressure they want. The refs then fill the balls to that pressure. All I was attempting to say was that if the footballs became warm either by handling or by being next to the boiler room or the laundry room, and if they were delivered in warm condition to the refs who immediately inflated them, then when they returned to room temperature they would be underinflated, and that's before they even reach the field.
If it is true that the Colts balls were up to par, and that the re-testing was conducted at room temperature,...
I've seen no explicit mention of where the testing took place, but I assume it was done on the field. To retest indoors would have required taking the balls indoors and waiting at least a half hour for them to warm up. Half-time is only 20 minutes at most.
--Percy

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 Message 25 by NoNukes, posted 01-27-2015 12:43 PM Percy has replied

  
Percy
Member
Posts: 22391
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


Message 18 of 466 (748450)
01-26-2015 7:53 AM
Reply to: Message 16 by NoNukes
01-25-2015 10:09 PM


Re: Science Takes the Stage
NoNukes writes:
And, the ball almost certainly was under inflated. I think the amount of deflation in question would be detectable. I have not much experience with footballs, but I can tell you that when I played a lot of basketball, I could easily detect small amounts (much less than 1 pound) of under inflation simply by handling the ball for a few moments.
By "handling the ball", do you mean the same kind of handling as for a football? Or do you mean by bouncing it, which you can't do with a football?
When I ran my own inflation experiment I couldn't tell the difference in pressure by handling the football, and Bellichick said the trials they ran picking out underinflated footballs revealed that it wasn't possible until the difference rose to 2 psi, and even then detecting it was pretty spotty.
I meant to comment on this one earlier. The Colt linebacker who intercepted a Brady pass in the first half says he did not detect anything wrong with the ball. Apparently someone he gave the ball to on the sidelines did notice.
Maybe someone with a gauge in his pocket?
--Percy

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Percy
Member
Posts: 22391
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


Message 21 of 466 (748534)
01-26-2015 3:39 PM


Bill Nye Gets it Wrong
In response to Bellichick's press conference Bill Nye said:
Rubbing the football, I don't think you can change the pressure. To really change the pressure you need one of these - the inflation needle.
He's wrong, of course. First, there's friction. Working up the football to rough up the surface to make it easier to grip will warm it up.
And Nye is wrong for another reason. The body is warmer than the football, and heat always flows from hot to cold. It never flows in the reverse direction, and in the presence of a heat gradient it doesn't stay put.
I recently replaced my old thermostats, and the new ones are much more sensitive. If you stand in front of them for a half minute or so, the temperature reading will increase. Body heat does have an impact. So if someone holds a football close to the body for for five minutes while rubbing it up then it will warm up the football.
These two effects, friction and increasing temperature, are enough to have a measurable effect. All Nye did was make an armchair declaration that Bellichick was wrong, but Bellichick's the one who performed some experimentation, and he *did* measure a pressure increase resulting from handling the footballs.
Nye does say, "To really change the pressure...", which is perhaps how he's saying that rubbing the football will only have some small effect, which is correct, but if that's what he meant then that's the only correct thing he said. I read a couple more mainstream press articles about deflation-gate today, and they definitely interpreted Bill Nye's statement as saying that Belichick has his science wrong.
But Bellichick does not have his science wrong. Despite what Bil Nye said, heat does flow from hot to cold, friction does cause heat, and pressure does drop with temperature. Even more impressive, Bellichick apparently didn't know or at least wasn't sure of these little facts of science beforehand but just discovered or verified them as he went along. All in all, it was a very nifty job of science experimentation. Bill Nye could learn something.
--Percy

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 Message 26 by NoNukes, posted 01-27-2015 12:51 PM Percy has replied

  
Percy
Member
Posts: 22391
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


Message 22 of 466 (748600)
01-27-2015 9:38 AM


It Just Doesn't Stop
There's been yet another leak from the NFL. According to Fox Sports, surveillance cameras captured the locker room attendant who carried the balls from the referees room to the field stopping off in a bathroom for 90 seconds. This is apparently enough to convict the Patriots in some peoples' minds. As one late night sports talk show host put it (paraphrasing), "90 seconds may not seem like much time, but you can be sure this isn't the first time they've done this, he has his act down pat, and 90 seconds was plenty of time." (I can hear Tom Brady thinking, "He stopped off in a bathroom? Hey, I have to throw these things!")
Robert Kraft, owner of the Patriots, gave an impassioned four minute speech upon arrival in Phoenix yesterday. He gave his coach and his quarterback solid votes of confidence, and he expressed strong disappointment with the way the NFL was steadily leaking partial information and inuendo in a way causing the issue to remain under media scrutiny and be tried in the court of public opinion with an absence of hard evidence and an abundance of misinformation.
Bellichick's public manner invites suspicion, but Brady doesn't deserve this. Troy Aikman and Mark Brunnell (former NFL quarterbooks) have both gone on record as not believing Brady. Even if they understand but reject the possibility that temperature could have significantly affected pressure and sincerely believe it could only have occurred through tampering, how can they ignore that anyone with access could have tampered with the footballs? I guess they can ignore what evidence eventually comes to light and just say, "Hey, Brady must have known." It's possible this will follow Brady around forever, regardless of the evidence. Nice work, NFL.
Kraft is possibly livid at Goodell. Kraft is the most powerful NFL owner, and if in the end it turns out the Patriots did nothing wrong then Goodell will likely be gone within a year or two.
--Percy

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 Message 24 by NoNukes, posted 01-27-2015 12:33 PM Percy has replied

  
Percy
Member
Posts: 22391
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


Message 32 of 466 (748631)
01-27-2015 2:10 PM
Reply to: Message 23 by NoNukes
01-27-2015 12:26 PM


Re: Science Takes the Stage
NoNukes writes:
Squeezing it between my hands, and attempting to 'palm' a basketball with each of my left and right hand would be enough to detect under inflation and over inflation of a standard size and weight men's basketball.
Impressive.
And yes you can bounce a football in a way that would help reveal under pressure.
And you can bounce a football in such a way? Again, impressive.
I would be complete surprised if a professional football player who handles the ball frequently was not even better at detecting inflation with a football that I am with a basketball.
Have you considered the possibility that your skill at detecting inflation pressure is just special? This video of Bellichick's 2nd press conference begins just as he's addressing the issue of inflation pressure. He addresses it in more detail later on, but at this point he only says detecting inflation pressure is difficult:
Bellichick said the trials they ran picking out underinflated footballs
He also does not play quarterback. Please describe those trials.
I'll do better than that. This video from later on in Bellichick's 2nd press conference begins just as he's describing those trials. He says that detecting a 1 psi drop wasn't possible, while detecting a 2 psi drop was hit or miss:
If you watch the entire video you'll see that Bellichick describes how the balls are delivered to the referees immediately after being prepped. Bellichick says being prepped can increase the pressure by as much as 1 psi, which is completely consistent with a ball increasing in temperature due to friction and proximity to a warm body. If the referees then inflate the balls right after being prepped (keep in mind that the referees are not inflating the balls from scratch, they're just adjusting the pressure to what the team requests) then there will be as much as a 1 psi drop when they return to room temperature, and another 1 to 2 psi drop when they are sent out onto the field where the temperature was around 40 degrees by halftime.
And why was one of the twelve footballs at a higher pressure than the rest? I proposed a possible scenario in an earlier message. The refs had inflated eleven footballs when they were interrupted. They had a 15 minute conversation, then inflated the last football, which had by then cooled to room temperature.
Or another scenario: They were interrupted just as the last football was about to be inflated, then misremembered that it hadn't been inflated and mistakenly marked it inflated. If the footballs had all originally been inflated around 13.5 then this last football would have had higher pressure than the rest.
Maybe someone with a gauge in his pocket?
Possibly. But perhaps that person had some reason to suspect under-inflation.
I'll bet he did have a reason. But that reason was likely that he didn't trust Bellichick and already had suspicions of underinflation, not that he could tell the ball was underinflated.
What most of the press coverage ignores is that there's no direct evidence of Patriot wrongdoing. The balls measured underinflated, but many factors affect inflation pressure.
Playing in the northeast in an outdoor stadium, it's not unheard of for the Patriots to have night games (around an 8:30 start time) where the temperature drops more than 20 degrees during the game. Keeping the balls within the legal range during these games would be a significant headache, but if everyone's so sure that inflation pressure can have so significant an impact on game outcome that purposefully tampering with it is cheating of the highest degree justifying calls for things like banning from the Superbowl, million dollar fines, loss of 1st round draft picks for years, etc., then the NFL better get right on this and put procedures in place that will guarantee that ball pressure remains in range for the entire game.
But if ball pressure is largely inconsequential, which it probably is, then this is far too much ado about nothing. But reputations are being trashed with no evidence (so far), and that's not right.
--Percy

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 Message 33 by Tempe 12ft Chicken, posted 01-27-2015 2:14 PM Percy has seen this message but not replied
 Message 34 by NoNukes, posted 01-27-2015 2:26 PM Percy has replied
 Message 36 by NoNukes, posted 01-27-2015 2:37 PM Percy has replied

  
Percy
Member
Posts: 22391
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


Message 37 of 466 (748636)
01-27-2015 2:49 PM
Reply to: Message 24 by NoNukes
01-27-2015 12:33 PM


Re: It Just Doesn't Stop
NoNukes writes:
That said, why are Aikman and Brunnel not credible to you?
They are plenty credible to me when they talking about what they know, but in this case they're talking through their hats. As quoted in Ex-players react: Brady‘s cluelessness ‘unbelievable’ Troy Aikman said:
Troy Aikman writes:
It’s obvious that Tom Brady had something to do with this. For the balls to be deflated, that doesn't happen unless the quarterback wants that to happen, I can assure you of that. Now the question becomes: Did Bill Belichick know about it?
I don't think Aikman is privy to any special knowledge. He doesn't know the balls were deflated, and if they were, he doesn't know Brady was involved.
Here's Mark Brunell:
Mark Brunell writes:
I did not believe what Tom had to say. Those balls were deflated. Someone had to do it and I don’t believe there’s an equipment manager in the NFL that would on his own initiative deflate a ball without the starting quarterback’s approval. I just didn’t believe what Tom Brady had to say.
Same for Brunell. He doesn't know the balls were deflated, and if they were, he doesn't know Brady was involved.
Some of the stories about the testing would seem to rule out changes in temperature being an issue, but who knows if those stories are accurate?
Given PV=nRT, how could temperature fail to be a factor? There is a lot being written out there that is self-evidently very ignorant of the ideal gas law.
--Percy

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 Message 24 by NoNukes, posted 01-27-2015 12:33 PM NoNukes has replied

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 Message 47 by NoNukes, posted 01-27-2015 4:36 PM Percy has replied

  
Percy
Member
Posts: 22391
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


Message 38 of 466 (748637)
01-27-2015 2:57 PM
Reply to: Message 25 by NoNukes
01-27-2015 12:43 PM


Re: Science Begins Receiving Mainstream Attention
NoNukes writes:
The temperature of the air in the ball is what determines the pressure/volume and not the skin temperature of the ball, which might be something different at least during filling. Your explanation should be about how hot air got put into the ball.
The increased temperature of the skin and bladder would be transmitted to the air inside. The footballs are already inflated when they're prepped, and they're still inflated when they're delivered to the referees. All the refs have to do is slightly adjust the pressure of each ball to the requested pressure. This only requires a slight pump or release - very little air would be added or released.
Seriously, Percy? You sound like someone who wants this pressure idea to work.
This is a strange take. It isn't a matter of wanting "this pressure idea to work." This is simple physics involving one of the most famous and honored relationships of all time, PV=nRT. It isn't a matter of wanting it to work but of carefully working out how much it was responsible.
So what happened to the 12 balls that were not under inflated?
There's a lot of misinformation out there. At this point I don't think we have much reliable information about the Colts' balls or the backup balls.
--Percy
Edited by Percy, : Grammar.

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 Message 25 by NoNukes, posted 01-27-2015 12:43 PM NoNukes has not replied

  
Percy
Member
Posts: 22391
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


Message 39 of 466 (748638)
01-27-2015 3:08 PM
Reply to: Message 26 by NoNukes
01-27-2015 12:51 PM


Re: Bill Nye Gets it Wrong
NoNukes writes:
A football is made of insulating material of unknown heat capacity. How long after you tucked the ball under your jacket would it take to see a significant pressure change. If you kept the ball against your skin for five minutes and then put it back on the table, how high would the pressure get?
While Bellichick didn't carry out these precise experiments, he *did* perform experiments, and he found that prepping the balls increased their pressure by around 1 psi.
Bellichick said he went through a normal game-day preparation of the footballs, so I assume that means he measured the pressure of twelve footballs, then had the quarterbacks (most likely with assistance, probably running backs and some staff) go through their normal prep, then measured the pressure again. He found the pressure increased by around 1 psi.
My pressure gauge isn't convenient, but if you have one that is you could give the experiment you proposed a try. Take an inflated football at room temperature, stick in a pressure gauge, put the football under your shirt with the gauge sticking out between buttons, then write down the pressure every minute and draw a graph.
--Percy

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Percy
Member
Posts: 22391
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


Message 41 of 466 (748641)
01-27-2015 4:02 PM
Reply to: Message 27 by Tempe 12ft Chicken
01-27-2015 12:54 PM


Re: Wilson, The Football company disagrees
Tempe 12ft Chicken writes:
According to representatives from Wilson, the company responsible for all of the footballs used in the NFL, Belichick's explanation is BS and doesn't factor in the bladders that each football contains, which do not let air escape them unless there is a defect in the bladder.
Source: Belichick full of hot air
A better link is one from within the article you linked to: 'That's BS': Football Manufacturer Doesn't Seem To Buy Belichick's Explanation. It includes the part you quote here:
Jim Jenkins, Wilson Representative writes:
different environments might cause the PSI inside the ball to change,but "maybe in a year or two." To cause the pressure to change more quickly, Jenkins suggested a ball would have to be placed in a freezer, then thawed.
So, who do you think would have run more experiments on the air contained within footballs, Belichick with his experiments he only ran recently, or the company that has made the footballs for the NFL for the past 70 years?
I think AZPaul3's speculation that the Wilson representative is talking about loss of pressure due to leakage is probably correct. The Wilson rep completely missed that Bellichick was talking about changes in pressure due to temperature fluctuations. That's easy to understand though. Bellichick was obviously unaware of what it was in the different "climatic conditions" (the term he kept using) between inside and outside, but anyone with a little science knowledge knows the overriding factor would be temperature. I think Bellichick's use of the term "climatic conditions" confused the Wilson rep.
Another scientist has come out stating that Belichick's experiments are not correct also, a man named Neil DeGrasse Tyson.
NdGT writes:
For the Patriots to blame a change in temperature for 15% lower-pressures, requires balls to be inflated with 125-degree air.
Source
...I'd like to see one of them actually run the calculations,...
I went through the calculations and Tyson is correct. If you plug the figures into the natural gas law, then in order for the gas at a temperature of 45 degrees to be 15% below it's original pressure of 13 psi, given constant volume the original temperature would have to been 125 degrees (all values approximate), 80 degrees higher.
But in my Message 8 I describe the experiment I conducted where I measured a 2 psi difference when changing a football's temperature between 30 and 74 degrees, a difference of a mere 44 degrees instead of 80 in Tyson's calculation. Obviously something else is going on since the pressure dropped by about twice as much as the ideal gas law predicts. My gauge is digital and reads in .5 psi increments, so that's a source of inaccuracy and could account for half the difference. But even using the smaller difference I can't imagine what might have caused it. It can't be decreasing volume, because that would increase pressure.
One possibility is that air is not an ideal gas. The ideal gas law postulates a monatomic gas, but air is made up of molecules of different gases like O2, N2 and CO2. Also, last Sunday night was very rainy, so humidity must have been at or near 100%, but figuring out how to adjust the ideal gas law for air with all its different molecules and humidity is above my pay grade. I did attempt to look it up but it was turning into a time sink.
--Percy

This message is a reply to:
 Message 27 by Tempe 12ft Chicken, posted 01-27-2015 12:54 PM Tempe 12ft Chicken has not replied

Replies to this message:
 Message 57 by NoNukes, posted 01-27-2015 7:48 PM Percy has replied

  
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