Deflate-Gate Calculations & Bill Nye

[arkie87]

So, Bill Nye recently put up another video about deflate-gate where he attempts to tackle the issue of whether or not the plummeting temperature could have reduced the ball pressure. Here is the video:

http://www.funnyordie.com/videos/3d0c94936c/bill-nye-addresses-deflategate

Some background information:

Internal pressure of the ball must be between 12.5-13.5 psi

Balls were found to be 2 psi below requirements.

Inside temperature might have been up to 80F (300K) , and outside temperature was around 50F (283K) that night.

He claims a 6% pressure drop by calculating the ratio of temperatures i.e. 1- 50F/80F = 1 - 283 K/ 300K ~ 5.5%. This is correct.

He then claims that this is off by a factor of 2.5. I assume what he means is 6%*13 psi = 0.78 psi, and 0.78 psi * 2.5 = 1.95 psi, which is close to the 2 psi deflation the league officials found.

However, he should not be using 13 psi, since this is gauge pressure; he needs to use absolute, which requires adding 14.7 psi. Thus, 6%*(13+14.7) = 1.662 psi, which is close to the 2 psi deflation the league found (and not a factor of 2.5).

Thoughts? Did i do a miscalculation somewhere?

PS: please only comment about the calculations, not about the controversy, or whether or not you think the patriots did it etc...

Edited January 30, 2015 by arkie87

[NFUN]

You mean the Ballocaust?

//im sorry

[Kryten]

Thoughts?

My thought is this whole situation is the stupidest manufactured controversy I've ever seen.

[arkie87]

My thought is this whole situation is the stupidest manufactured controversy I've ever seen.

Who cares about the controversy!!! I care more about Bill Nye (supposedly) not being able to do basic physics calculations....

[Guest]

It very well could be a media manufactured controversy just for ratings and money. I haven't heard a report that lays out all the facts yet. Chris Carter raised a good point at the Pro Bowl when he asked why weren't Indianapolis's balls the same as New England's. If Indy's balls were below the regulation as well as New England's, there would have been no controversy. Chris Carter seemed to be saying that New England was cheating because of this line of reasoning : New England's balls were flat at halftime, Indy's weren't. But like I said, we don't know all the facts, or at least I don't. What were the starting pressures for each team and what were the halftime pressures for each team? It may turn out the the only idiot in this game is ESPN.

edit : or maybe Bill Nye.

Edited January 30, 2015 by Otis

[arkie87]

It very well could be a media manufactured controversy just for ratings and money. I haven't heard a report that lays out all the facts yet. Chris Carter raised a good point at the Pro Bowl when he asked why weren't Indianapolis's balls the same as New England's. If Indy's balls were below the regulation as well as New England's, there would have been no controversy. Chris Carter seemed to be saying that New England was cheating because of this line of reasoning : New England's balls were flat at halftime, Indy's weren't. But like I said, we don't know all the facts, or at least I don't. What were the starting pressures for each team and what were the halftime pressures for each team? It may turn out the the only idiot in this game is ESPN.

Could someone please comment about the calculations themselves. not the controversy...

[Guest]

Could someone please comment about the calculations themselves. not the controversy...

The title of your OP contains "Deflate-Gate". Sorry if I ruined your day bay discussing "Deflate-Gate". Maybe someone can help you with the math of Bill Nye. I really don't care whether or not Bill Nye can add and subtract.

[arkie87]

The title of your OP contains "Deflate-Gate". Sorry if I ruined your day bay discussing "Deflate-Gate". Maybe someone can help you with the math of Bill Nye. I really don't care whether or not Bill Nye can add and subtract.

Didnt mean to imply you ruined my day. Just want to discuss the calculations, not the controversy. I have revised OP title accordingly.

[EdFred]

Or just head over to headsmartlabs.com where they actually do the experiment rather than do the math.

[KerikBalm]

It would seem that you would want to take absolute pressure, and Bill Nye may have overlooked this.

Often when talking about PSI, we're talking about thing pressurized so high, that 1 atmosphere doesn't change things very much.

It does seem like an oversigt by Bill.

Also note that temperature could have been higher than 300k, air heats up when compressed, if the air was already in the high 70's (F, thats nearly 300 K), it could have been a bit over

[arkie87]

Often when talking about PSI, we're talking about thing pressurized so high, that 1 atmosphere doesn't change things very much.

It does seem like an oversigt by Bill.

I dont know about "often" (even 80 psi in a bicycle tire, ambient pressure of 14.7 psi is still significant), but it is always important to know whether ambient pressure is significant or not. In this case, it definitely is.

Also note that temperature could have been higher than 300k, air heats up when compressed, if the air was already in the high 70's (F, thats nearly 300 K), it could have been a bit over

Yes, i thought about this too. If a hand pump/bicycle pump/compressor was used, then pressure would decrease as air inside cools. This effect can be significant. If a storage tank filled with compressed air was used, which already had a long time to cool down, then i dont think this effect should be included. I cant say if they used a compressor or a tank, though.

[How2FoldSoup]

I have no comment other than using the ideal gas law is pointless for real world conditions...

Edit: Here's what I wanted to post

ideal gas law != real life in the slightest. Go stick the ball in your fridge and get real data.

Edited January 30, 2015 by How2FoldSoup

[Skyler4856]

Oh, yeah, because we don't have anything more important to deal with as a nation, or as a culture for that matter. No, the pressure of the balls of one meaningless game definitely deserves this much attention...

[xcorps]

Oh, yeah, because we don't have anything more important to deal with as a nation, or as a culture for that matter. No, the pressure of the balls of one meaningless game definitely deserves this much attention...

Uhm, the AFC championship determines who goes to the Superbowl. The last 5 superbowls are the most watched television events in the United States. Networks sell airtime at 9 million dollars a minute for advertising. The Superbowl in New Orleans was estimated to draw almost 500 million in tourism revenue for that single event.

Not meaningless.

You don't think the most attended and most watched sport in the world is an important part of American culture? What exactly is your definition of culture?

Edited January 31, 2015 by xcorps

[*Aqua*]

most attended and most watched sport in the world

The most wached sport is football. While probably a lot of the 340 million US Americans watch American football, 540 million Europeans are crazy about football (soccer). FIFA estimates that 265 million players are kicking balls worldwide. (pun intended )

[Kerbart]

You don't think the most attended and most watched sport in the world is an important part of American culture? What exactly is your definition of culture?

I don't think it does, although it's slowly getting there. But what does "association football" ("soccer") have to do with this?

[PakledHostage]

But what does "association football" ("soccer") have to do with this?

I think he's talking about hand egg... It's an obscure sport, peculiar to North America but largely unknown in the rest of the world.

[Hasegawa]

I have no comment other than using the ideal gas law is pointless for real world conditions...

Edit: Here's what I wanted to post

https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcRMNbt5h7MEBj2H2YyUdEzefuC0Oy3NJDr2zbM5GKxSXlpTt-LScA

ideal gas law != real life in the slightest. Go stick the ball in your fridge and get real data.

Compressibility factor (a correction factor for the ideal gas law for when it actually matters) for air at 300 K and 1 atmosphere of pressure is 0.9999. At 5 atmospheres and 300 K is 0.9987. That means the error for using the idea gas law is on the order of 0.13%. Which is quite probably smaller than the uncertainties in the instruments used to measure the data.

So no, ideal gas law is perfectly fine for these conditions.

[Nuke]

and this is why i will be watching the kitten bowl instead.

[Zuqq]

All I have to say about this video is.... Bill Nye said the F word. My childhood was just changed.

[EdFred]

I think he's talking about hand egg... It's an obscure sport, peculiar to North America but largely unknown in the rest of the world.

Considering there are only 300,000,000 people in the US and over 2,000,000,000 watch it world wide, I would hardly say it's unknown.

[epoca]

Considering there are only 300,000,000 people in the US and over 2,000,000,000 watch it world wide, I would hardly say it's unknown.

It's definitely not unknown, but it's also definitely not the most popular sport worlwide. But I guess we are veering off topic, so let's get back on track.

[EdFred]

It's definitely not unknown, but it's also definitely not the most popular sport worlwide. But I guess we are veering off topic, so let's get back on track.

It may however be the most single watched sporting event.

I don't consider the World Cup with all of its matches a single event. Nor Wimbleton, etc...

[lincourtl]

Oh, yeah, because we don't have anything more important to deal with as a nation, or as a culture for that matter. No, the pressure of the balls of one meaningless game definitely deserves this much attention...

http://imgs.xkcd.com/comics/super_bowl.png

[PakledHostage]

[RANT]

The assumption that you and Randal appear to be making is that the conversation DOES go both ways. Trouble is that we tend to overinflate the importance of sports while ridiculing or downplaying interests in STEM fields. More often than not, the "jocks" won't take the time to reciprocate after you've taken the time to "share their excitement". I am certain almost everyone on this forum has experienced it.

You can try to "fit in" by being someone you're not and feigning an interest in something you find tediously boring, or you can try to find people who accept you for who you are. Sometimes it is "politically expedient" to feign interest, but political expediency does not equal friendship.

[/RANT]