The science behind Brazuca, the official ball of the 2014 World Cup

Brazil still needs to complete three stadiums, but their official soccer ball, the Brazuca, is perfect, scientists say.

Image:Adidas/Wikipedia

A conventional soccer ball has 12 black pentagons and 20 white hexagons, good enough for a friendly match with your mates. But that design is so last century when it comes to the innovation needed for the 2014 World Cup.
Researchers in Japan compared the stability of the Brazuca, the official ball of this year’s World Cup, with other soccer ball designs used over the past five years, including the 14-panel Teamgeist 2, which was introduced in the 2008 Euro Cup, and the Jabulani, which was used at the 2010 World Cup in South Africa.
They tested the balls in wind tunnels to see if the wind changed the trajectory mid-air or if it affected the side and lift forces. Over at the LA Times Karen Kaplan explains the results of three tests:
The wind tunnel experiments revealed that the Brazuca was tops when it came to the stability of the drag forces (or air resistance) acting on the ball. All of the balls were tested in two different orientations, and the results for the Jabulani and the Cafusa were quite different depending on which side of the ball was facing into the wind. But the plots for the Brazuca were nearly identical in both conditions.
Another set of wind tunnel tests measured the side and lift forces of the balls as their (simulated) velocity increased from 20 to 30 meters per second. (In reality, the balls remained stationary and the wind blew faster.) Once again, the Brazuca performed well (though the Teamgeist 2 was better) and the Jabulani performed poorly.
In the final set of tests, each soccer ball was struck 40 times (20 times in each of two orientations) by an “impact-type kick robot” that delivered the ball to a goal net 25 meters away. The Brazuca and the conventional ball were most likely to wind up in the same part of the net after each kick. The flights of the other balls changed quite a bit depending on which side was facing the kicking robot.
The 8-panelled Jabulani, designed by Adidas, got the worst scores when it came to drag and both players and coaches have criticised its design, claiming that its trajectory tends to change direction.
But soccer teams will be happy with the Brazuca, also designed by Adidas. It has a circumference of 27 centimetres, six X-shaped panels that guarantee constant weight and roundness.
Let the games begin!