Materials Mystery: NFL Footballs

Tomorrow night a new season of NFL football begins. With it comes 21 weeks of pizza, wings, beer and pretending you're on the team (that "we" pronoun gets used excessively). And rather than play real sports, we'll play fantasy sports, because real sports means getting off the couch on a Sunday. There is ten minutes of action in our three-hour-long game, which means it's perfect for our minuscule attention spans. I suppose it's easy to see why football has supplanted baseball as America's national pastime.

And yet this game wouldn't be possible without some oft-overlooked materials science, which includes some closely guarded secrets.

The first footballs of the 1870s were actually spherical, and resembled 'futbol' footballs more than anything else. When a club match between McGill and Harvard first used a rugby ball instead, the players found the ball easier to carry, with a moderate improvement of its throw-ability. The rugby ball remained the premier option for American football games until 1912, when college football implemented an oblong ball which resembled the footballs we know today-except they were almost twice as big.

While ball geometry (technically called a prolate spheroid) was figured out , too often footballs became deflated during the middle of a game. Originally, balls had a metal or rubber inflation stem protruding from its profile. Lace stitching was used to hold the stem flat against the ball, but also helped quarterbacks (who had recently been granted the forward pass) throw tight, spiraling passes. In 1924, Wilson Sporting Goods introduced a dual-lined football, and shortly after eliminated the valve stem. Next, the NFL reduced the ball's short axis diameter to 21.25 to 21.5 inches (a decrease of about 1.5 inches) and its long axis length to 11 to 11.25 inches (when it was previously 28 inches). These innovations significantly improved ball durability, and after buying out their closest competitor, Wilson became the sole supplier of footballs for the NFL.

Secret #1: tanning process

Several different material compositions were attempted for Wilson footballs, but they proved too slick or were ugly. In 1955, leather supplier Horween Leather Company implemented a proprietary process it calls Tanned in Tack that imparts stickiness to the cow hide (not pig hide) that other tanning companies have had difficulty mimicking. Another development, this one 26 years later, embossed a rough pebble-grain texture to the leather exterior. Horween's excellent leather conditioning has made them the exclusive supplier of NFL-grade leather since 1941.

Secret #2: mystery bladder

Since then, footballs have been assembled with a three layer bladder. Two of them are composed of polyurethane, while the last layer is a Wilson company secret. The four leather panels of the ball are cut, quality checked, and hand sewn before the bladder is inserted. While minor stamping or logo changes progress almost every year, football construction is easy to trace back to its nostalgic roots.

There you have it CR4ers: unless you can put together the secrets behind football assemblies, you're better off just watching the game and enjoying it.