I am not usually much of a football guy and most of my sports related posts here will be either about baseball or running, but this week on social media has been all about football, and became a major topic on my personal Facebook wall. As I alluded to in previous posts, I am a chemistry professor at a mid-sized state university. As a result, I have some friends in the Physics department, one of whom happens to be a big time Patriots fan. I don't hate the Patriots, and on the occasion that I watch football at all, I am a Packers fan, so I really didn't have a horse in this race, but it became more and more fun for me to watch the drama unfold on Facebook, especially from a science perspective.
Because of my initial lack of interest, I stayed out of it for a while, but my Patriot-fan-Physics friend made a post that caught my eye. In his initial post, he corrected an initial media science faux pas wherein a particular media outlet had correctly done their algebra in calculating the pressure drop to be expected from the temperature drop that occurred in going from locker room to field, but had inserted the wrong pressure number into the equation. You see, when it is stated that the pressure to which the football is pumped is 12.5 pounds per square inch, that is not the total pressure inside the ball, that is the pressure difference between the inside of the ball and the outside. Normal atmospheric pressure is about 14.5 pounds per square inch, so to do the calculation correctly, one has to begin with a total pressure of 27 pounds per square inch. My friend worked the calculating this way and found that the total pressure after the temperature drop would be around 24 pounds per square inch, making the gauge reading on the ball 11.5 pounds per square inch, vindicating the New England Patriots.
So, not because I care so much about the football outcome, but because I loved the idea of gas laws being applied to popularly followed news events, I shared my friend's status on Facebook and added a few funny jabs of my own quoting Big Bang Theory and Bernie Mac to get the discussion going. One of my oldest and dearest friends, an ivy league educated engineer, called us out on our physics, claiming that the assumption we made of constant volume would not be true, that the drop in temperature would cause both a volume AND a pressure reduction, each offsetting the other a bit, thus calling into question the significant pressure drop seen in the Patriot footballs. I saw his point, but wasn't sure that the volume change in a ball the consistency of a football would be significant at that pressure, but geekiness took over and we began designing an experiment to conduct in the Physics lab at the university that I would have posted on here had we got it done, but alas, the physicists at Carnegie Melon beat us to it and have already posted their findings which are detailed in another person's blog:
News Cut's Blog on Carnegie Melon's Deflategate Study
Long story short, my Patriots-fan-Physicist friend was correct, the volume change was negligible and the pressure drop due to temperature change was more than 1 PSI. Additionally, the pressure drop due to getting the ball wet was also nearly 1 PSI, making the Patriots appear totally innocent of all charges related to deflategate. As an added bonus, one of Professor Alkahest's greatest foils, Bill Nye the Pseudoscience Guy, came out with his opinions on the matter right at about the same time, but without having verified his opinions with appropriate experiments (as he often does) and got it completely wrong. It is important to note here that Bill Nye was allowing his bias as a Seahawks fan to effect his scientific judgement (as shown by video evidence). If you would like to see Bill Nye embarrassing himself by ignoring the Combined Gas Law and claiming that the only way to change pressure is to change the number of gas molecules in a container please go to this address and prepare to giggle (notice that his experiments use giant orange party balloons instead of actual footballs... OH THE RIGOR ... heeheehee):
Bill Nye being silly on deadspin
Morals of today's stories:
1) Any news item that causes people to learn a little science is an awesome news item.
2) Science beats engineering, always and all ways.
3) We are only having this ridiculous conversation because the NFL is stupid enough to allow the game balls to be prepared and controlled by the participants in the game rather than by the officials. In intelligent sports, the officials have control of the game balls until they come into use. Therefore, baseball beats football, always and all ways.
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