J Does A Bunch Of Brady Math

Ok – so this isn’t a sports blog, but I think this crosses over sports/nerd, so here goes. Big news in NFL this week is the Patriots being accused of cheating for having balls inflated approximately 2 PSI below the league minimum requirement, which many people feel would be an advantage to the offense in poor weather conditions. A common response from Pats fans is that the temperature difference between the locker room and the field would explain the measured difference. But, since this is ‘merica, and no one can do the maths, nowhere have I seen any actual estimate of the size this effect. So, I busted out my old friend PV=nRT. OK, so here’s the setup:

P1 = 11.5 PSI (chosen as the minimum – most favorable Pats assumption)
T1 = 70 Deg F
T2 = 30 Deg F
P2 = This shit ain’t known. The whole purpose of this exercise is to find this. Get with the program.

That’s right, I’m using imperial units. Deal with it, bitches.

Locker room:

P1V=nRT1

Field:

P2V=nRT2

A little algebra gives us:

P2=P1(T2/T1) since everything else is constant.

But.. we have to work in metric, because all this imperial shit doesn’t make sense, and we need to use absolute temperature, so Deg K.

Which means:

P1 = .0793 MPa
T1 = 294.1 K
T2 = 272.04 K

So P2 = .0734 MPa = 10.65 PSI

So, I’ll give the Pats 1PSI difference, but 2? That would require a temperature swing of 92F. So unless these balls were stored in a 120 Deg sauna, I’m calling bullshit on this one.

4 thoughts on “J Does A Bunch Of Brady Math

  1. First off, this blog is about whatever the fuck we want, so there.

    Second, and more importantly, where did you learn to write numbers like that? Can you see the matrix? Heresy! Off with your head!!

    But, really, good point re: seeing the actual math on this. This is the first I’d seen it. It’s blatantly obvious they did this on purpose. That said, maybe all teams do. *That* said… Have you seen this Slate article? I think this is a damn good explanation for why they would want deflated balls:

    http://www.slate.com/articles/sports/sports_nut/2015/01/ballghazi_the_new_england_patriots_lose_an_insanely_low_number_of_fumbles.html

  2. Well, shit. I just realized I should be using absolute pressure instead of gauge pressure (gauge pressure will measure the difference to atmosphere.) Using absolute pressure, you come up with almost exactly a 2 PSI drop from temperature alone. So… if they started right at the low end of the scale, and the air in the balls was reasonable warm when filled this could explain the entire difference.

  3. I also read that the moisture on the field could have affected the pressure. Still, this is Belicheat, I don’t care about the math.

    1. Oh – He definitely did something. I imagine it was something that was technically within the rules (ie the balls would pass inspection) but would then deflate quickly. He could do that by pumping them up with wet air. The moisture would condense, and lower the pressure more than just the atmoshperic temp would do.

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