The NFL found out about the deflated footballs because during the game, one of the Colts players intercepted a ball, and during half time, he asked his coach to weigh it, and they found that it was underweight. The referees weighed the Patriot's balls, and found 11 out of 12 balls were deflated. The ball pressure matters because deflated footballs make it easier to throw and catch, mainly during rainy or other bad weather conditions.

During half time when colt handled the balls they found it to be a lot lighter than its usual weight, which is 12.5-13.5. Also, the ball pressure does matter because it increases it's distance height and grip and most football plays would say a deflated ball has a lot better brio than a regular ball.

The bid debate going on between the football fans ,Is did the patriots Cheat against the colts by using deflated footballs ? According to NFL rules , each team is allowed to bring 12 which is required to be inflated between 12.5 pounds and 13.5 . 11 out of the 12 bod the patriots balls were inflated .

They found out because when the Colts handled the balls, they said that they felt lighter than usual, so the referees weighed the balls, and it turnes out that they weren't up to NFL standards.