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26 January 2015

Embrace Chaos: science teaching and New England's deflated footballs

Which football is Belichickian?
In the runup to Super Bowl XVXIVXIVXIVXIVIXVIX, the NFL is investigating the New England Patriots for, perhaps, systematically underinflating the footballs they use on offense.  The sports media has gone crazy wearing out the "deflated ball" meme with puns and giggles well below the maturity level of the 9th grade boys I teach.  

In the true spirit of American anti-intellectualism, those who live outside New England condemn the popular and successful Patriots for cheating without waiting for any evidence better than "Cheater, Cheater, Pumpkin Eater."  Meanwhile, those who live *in* New England reflexively condemn the haters who dare to impugn the saintly Pats, even though not even his staunchest supporters would deny that head coach Bill Belichick would trip his own aged grandmother in a race if doing so raised the probability of victory.  

[For those of you who do not follow American football, the above paragraph must sound made up.  Trust me -- the students, faculty, and staff of my school have talked about little else for days.]

Our department has been asked to articulate "best practices of science teaching," things that we do that might be foreign to teachers in other disciplines.  Paul the chemistry teacher's response: 

Embrace chaos. What I mean by that is that, while organization and having a plan for where a lesson is going are important, it's equally important to leave room for serendipity. The "what would happen if we do this?" question that I'm not expecting is one that, as often as possible, I try to answer with "let's try it and see." Those questions are little clues as to what about the topic is going to be the hook of interest that keeps the student going through the difficult parts. Those are also authentic science experiences, in the sense that it's the way science really works---someone has a question and tries to find out the answer, and that investigation doesn't always go in the expected direction.

Paul embraced the chaos of the sports media's obsession with inflation pressure of footballs.  He asked the football team equipment manager to provide him with two new footballs, one inflated to 12 psi, one to 10 psi -- this was roughly the originally reported difference between legal footballs and Patriots footballs.*

*subsequently, it was found that reporters or someone had exaggerated -- the Patriots footballs were only 1 psi short of legal, not 2 psi.  That's going to be important to the next calculation.

First he had his students thrown the footballs around a bit.  While they all suspected that at least one was illegally deflated due to their overexposure to the sports media's "deflategate" meme, to the students both felt like normal footballs.

Next, Paul revealed that sure enough, one football was legally inflated, and one was underinflated.  He asked the class to handle the footballs and guess which was which.  The results showed that, even upon close examination, noticing the difference was pretty much a random proposition.  Paul is not entirely sure of his notes, but either his students today identified the correct ball by a 19-13 margin; or, they were dead split, 16-16.  I made my own guess, which happened to be right, but I was in no way sure of myself.

Finally, Paul introduced the ideal gas law to his students by way of a football inflation calculation.  We checked that a football was properly inflated to 12 psi in our 20 degree Celsius office.  Imagine now that we take the football outside on a 50 degree Fahrenheit day, like the day of the most recent Patriots game.  That would drop the Kelvin temperature by about 4 percent.  By the ideal gas equation, that would likewise drop the absolute pressure in the football by 4 percent.  Absolute pressure in the football would be the 12 psi gauge pressure plus the 14.7 psi atmospheric pressure.  Reduce that by 4% and then subtract the atmospheric pressure again and you find that the gauge pressure would drop to... 11 psi.  Down by 1 psi from the legal standard as measured by the officials before the game.  And exactly what recent reports indicate was measured by the NFL.  And that's a controversy, apparently.  

We haven't had the time yet to do the experiment -- we should leave the ball outside overnight to see if the pressure reading does in fact change by 1 psi or more.  That's next on the list.

Now, if Paul wanted to make this lesson truly interdisciplinary, he might discuss how the NFL conveniently leaked word of their investigation, knowing that the two-week media vacuum leading up to the Super Bowl would thus be dominated by ball inflation questions rather than pointed queries about the NFL's coverup of multiple instances of domestic abuse by their players this season.  Or Paul would discuss Mike Tanier's investigative report that found the Patriots footballs to be primarily filled with nitrogen.*  But Paul says he'll stick to chemistry.

* as well as the wonderful responses from the humor- and science- impaired.

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