Cold Weather Shrinks Footballs but not Egos

Somebody mentioned Bill Nye in a comment, and that set me off! In a discussion of Israel, Bill Nye has said places like France and Germany (bad choice) were “home” for Jews. He also calls himself the Science Guy, but for some reason, he has never made a point of letting people know he is not a trained scientist. He has a BS (not a Ph.D) in mechanical engineering, which is science-aided but not science. Finally, he has a reputation for rude diva behavior. These factors, combined with his bowtie, resulted in him being added to my list.

Bill Nye weighed in during the Deflategate scandal. The New England Sport-Ruining Cheaters…I mean “Patriots”…were accused of using partially deflated balls to make the game easier for them. Defenders (the kind of people who beat other people up in stadiums for wearing the wrong color socks) chimed in and said the pressure problem was caused by the temperature difference between the field and wherever the balls were inflated. Gases contract when cooled.

Bill Belichick, the Snoke of the NFL, came up with a truly weird theory. He said something about players rubbing the balls a lot, causing them to heat up and expand. I haven’t played football since phys. ed. class in high school, but I think I know enough to state, with confidence, that rubbing the footballs vigorously is not a normal part of the game.

Nye gave a ridiculous interview, and he brought a prop, which was an air pump with a needle. He said that in order to change the inflation pressure of a football, one would need “one of these.”

Let’s talk about the ideal gas law. In fairness to Nye, for all I know, this may not be a topic covered in a basic ME program. It is, however, a topic covered in HIGH SCHOOL CHEMISTRY.

Bill defends his science credentials by saying he took 6 semesters of calculus (physicists take 8 or more, but never mind). The ideal gas law doesn’t involve calculus. You should be able to master it when you’re in the fifth grade.

Here’s what it looks like: pV=nRT, or as I called it when I was trying to memorize it, “PIVNERT.” The small P is pressure. The V is volume. The n is the number of moles (kilomoles, whatever) of gas. R is the ideal gas constant, which is something that works with plain old air, even though it may not smell ideal to you. T is temperature, measured from absolute zero.

The pressure inside a football varies with temperature, Bill. That’s science, by the way.

I sat down today, and in a few minutes, I came up with a figure. I am not totally sure about the units, so I may be wrong, but it looks like the pressure inside a football ought to change by about half a pound per square inch per ten degrees Fahrenheit.

I think I’m right, because I see people who claim to know what they’re doing, citing pretty similar figures. If I were wrong, I would probably be off by one or more decimal places, because the dimensional errors would come in multiples of 10. I don’t think a ball’s pressure will change by 0.2 or a whopping 20 pounds over 40 degrees.

I guessed that a ball contains about 2 liters of air, and I figured that’s about a tenth of a mole of air, because of the Gay-Lussac law. Air doesn’t really have moles, but you can pretend it does, and it works.

Hmm. Turns out it’s Avogadro’s law. Whatever. Some foreigner or other.

Some of the figures don’t matter when you’re figuring pressure changes, because they cancel. It’s not a hard problem.

I’m too lazy to make absolutely sure I’m right, but I’m working harder than Bill Nye.

Football is a cold weather sport, which is one of the many good reasons for not watching it. Baseball players go home at the first sign of a cloud. Football players stay on the field when it’s zero degrees. Earthquakes, tsunamis, hail, locusts…you play, and if you die, you walk it off.

Let’s say a ball is pumped up in a 70-degree locker room or Chamber of Referee Mysticism or whatever. Then you put it on a field where the temperature is 30 degrees. That’s about two pounds of pressure lost, once the ball gets cold. Don’t know how long that takes, but air doesn’t hold a lot of heat, so it shouldn’t take long to cool a football.

NFL balls are supposed to be pumped up to 13 psi, but because no one wants to be a royal pain, it’s actually 13 +/- 0.5. The NFL found that Patriot cheater balls were something like 1.5-2 pounds low. That seems to fit in pretty well with science, but I still think they cheated because they’re the Patriots.

Anyway, I don’t get Bill Nye’s claim. If you’re going to call yourself the Science Guy and probably apply for a trademark, and you have time to dig up a football pump before an interview, you have time to look up the science. Takes maybe three minutes, if you’re slow. Maybe Nye had no idea what the ideal gas law was. Maybe he managed to get a degree without learning it, or maybe he forgot because he’s old.

I would certainly expect an ME to learn about ideal gases.

There is a Youtube video of an MIT professor giving what is presumably an authoritative lecture on Deflategate. Unlike Bill Nye, he is a Ph.D. mechanical engineer, and since he teaches at MIT, he may very well be a true Science Guy. Whatever he is, he should be able to handle pV=nRT. I didn’t watch the video however, because it was like 15 minutes long.

My guess: Bill Nye didn’t “like” the MIT video and send links to all his friends.

Okay, I’ll cheat (like the Patriots). I looked at the money parts of the MIT video. The prof’s findings match mine to within something like 10%, and unlike the prof, I didn’t even measure anything. I just winged it. Hello, it’s not hard. A football is about the size of a two-liter soda, so I said two liters of air. That’s about 10% of 22.4 liters (volume of a mole of ideal gas at STP, which is not all that far off from 70 degrees F), so 10% of a mole. It worked.

Real scientists don’t measure unless they have to. A good scientist can guess at a lot of things and be within 10% of the truth. I’m a bad scientist, and I can do it. A good scientist knows when a guess is good enough. Look up, “How many piano tuners are there in Chicago”?

People who get overly excited about precise figures and taking advantage of all 14 digits displayed on their calculators don’t know anything about science (or significant figures). Sometimes you need great precision, and sometimes it just gets in the way, and a real scientist knows the difference.

Anyone can be wrong about science, but the ideal gas law is 10th-grade stuff. Very obvious. If Nye can’t figure football pressure out, how can he be taken seriously when he claims he knows about the climate?

The Patriots still cheated. That much is obvious.