Physics shows the relationship between air pressure and temperature. NFL footballs “The Digest of Rules of the NFL explains the official size requirements for the football,..
The length should measure about 11 inches from tip to tip, and the in circumference at the center of the football should measure about 22 inches.

Air pressure is specific in the NFL, too. The ball is inflated to about 12.5 to 13.5 lbs. per square inch. A 2 psi tolerance is acceptable meaning a football inflated to 10.5 psi meets the inflation requirements. Note that’s three psi lower than 13.5 psi.

An air compressor increases the temperature of the air during compression. If the temperature of the air being put in the football is 150 degrees Fahrenheit and the pressure of the ball is measured as 10.5 psi the ball would meet the inflation requirements.

If the ball is used when the temperature is 25 degrees as it often is in January the air in the ball would shrink and the pressure would drop significantly below the 10.5 psi. The “Gas Laws” show pressure drops when the temperature drops. When the temperature of the air changes from 150 degrees at inflation to 25 degrees on a winter day, a 125 degree difference the pressure would make the correctly inflated ball change from 10.5 psi to 8.2 psi. As a reference the pressure in the tires on your car would change 21% from inflation in the summer to being checked in winter when it’s 20 degrees. From a correctly inflated tire at 30 psi in summer the pressure would drop to 23.6 psi in winter.

If the pressure in an NFL football is checked before the game by the referee in the heated locker room at 70 degrees and checked again at the end of the game when the outside air temperature is 25 degrees the pressure would drop about nine plus percent from 10.5 psi to 9.5 psi. That’s physics.

Note that 9.5 psi would be 4 psi lower than the highest pressure of 13.5 psi; the ball would be softer; it would feel softer and Coach Belichick, the Patriots and Tom Brady would be and most likely are innocent.

Here’s the take-away for all you high school students who are studying physics. You can do the calculations with a simple bit of arithmetic. To all those who don’t want to study physics, maybe you should consider doing it. You could be on a jury. You could get to the truth with physics and find a bunch of falsely accused people innocent.

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