Jesus Diaz in Sploid:
Every four years there is a new World Cup ball and players have to adapt to its new behavior due to changes on its aerodynamic properties. Players hated the 2010 ball—Jabulani—for its unpredictable moves. Has the new 2014 ball—Brazuca—solved these problems? NASA has the answer.
In South Africa, players said that Jabulani sucked. I remember watching the interviews with the Spanish team—the cup winners—and they all bitched about it. “It behaves like a f*cking beach ball” was the most common complain. The problem was the knuckling.
The previous World Cup ball, the Jabulani, was described as sometimes demonstrating “supernatural” movements […] when kicked with little or no spin, the ball “knuckled,” […] Knuckling occurs when, at zero or near-zero spin, the seams of the ball channel airflow in an unusual and erratic manner making its trajectory unpredictable.
The lack of precision affected the entire game, so most players hated it. According to NASA, Adidas “worked with hundreds of players to develop the Brazuca football” to solve this “supernatural” behavior.
They introduced some changes: While a traditional football has 32 panels and Jabulani has eight, the Brazuca has only six. The Brazuca's panels also have a rougher surface.
More here.