When a football is inflated in a room of 1 temp and then taken to a different temp the PSI of the ball will vary.
If the ball is wet the PSI and weight will change.
The following video explains how the ball reacted during the Colts Pats game. :
https://www.youtube.com/watch?v=CxsXFX3tDpg
My understanding is that balls are inflated to 13 psi, that 12.5 is the min and 13.5 is the max. At 13 psi the balls would have tested at approx. 12+ psi. by this test. Also that a temp alone would cause the balls to lose 1 psi with a drop in temp from 92 to 50 degrees. Also was not discussed was water saturation and time of temperature and moisture exposure. I assume the balls are kept under a cover during rainy weather and I have seen attendants towel drying balls on the sidelines. Why didn’t the balls the Colts used lose pressure or why weren’t that checked if they didn’t? Was this “scientific test” done by any chance at MIT in BOSTON. Of course we would still be having all this discussion if NE didn’t have a reputation as cheaters.