Panels, seams, power: Brazuca, ready for World Cup

WASHINGTON — With the 2014 World Cup 49 days away, Brazil is still scrambling to finalize stadiums and build hotels. But one key part of the game is complete and ready for kickoff: the ball.

The official ball of the 2014 FIFA World Cup is the Brazuca — a soccer ball Adidas spent two and a half years researching, creating and testing.

This may seem like a lot of time and effort for a ball, but after receiving criticism from players and coaches during the 2010 World Cup about that Cup’s official ball, the Jabulani, some say it was necessary.

“[Players] noticed it was almost like a beach ball. It just had these really weird knuckling effects; it would move side-to-side in crazy ways,” says John Eric Goff, professor of physics at Lynchburg College and author of “Gold Medal Physics: The Science of Sports.”

Goff says negative feedback from players is not uncommon when a new ball is introduced.

“I think any time a ball’s released, you’re going to hear goalkeepers complaining a little bit about it,” he says.

However, the Jabulani was called “dreadful,” “difficult” and “a disaster” by players on the field, as well as those in goal, during the 2010 games.

This year, Goff anticipates that players will find the re-modeled ball smoother than the Jabulani — and he explains why.

The Science Behind the Ball

The traditional soccer ball from childhood games is a classic 32-panel design that contains 20 hexagons and 12 pentagons. Goff says this design was mostly used through the 2002 World Cup in Japan and South Korea.

In 2006, Adidas, who has provided the official World Cup ball for 40 years, developed a design that deviated from the traditional soccer ball. The new design was a thermally-bonded 14-panel ball called the Teamgeist.

“The goal is always to get something that’s a perfect sphere. You’ve got to inflate it; you’ve got to put a bladder inside of it; you’ve got to do all of these technical things to make something that seems simple — you know, a ball,” says Goff, who has been studying the physics of sports for nearly 12 years at Lynchburg.

In 2010, the number of panels on the ball was reduced again — to eight. Goff explains that reducing the panels on the ball makes the ball smoother because there aren’t as many seams on the outside. But a smoother ball isn’t necessarily a faster one.

Adding roughness to the surface enables the ball to have a better “flight” — think of dimples on a golf ball.

“The rougher surface actually reduces the air drag,” Goff says. “When you say that to people, it often sounds counter-intuitive. You think if you were going to make something more aerodynamic you would polish it and make it really smooth.”

This year’s ball has two fewer panels than the Jabulani, but the seam length is 68 percent longer.

“Those longer seams make for a longer total seam length. It is that longer total seam length that helps make the Brazuca’s surface rougher than the Jabulani’s. The boomerang-shaped seams also help make the surface roughness more uniform on the Brazuca, leading to more stable flights compared to Jabulani,” Goff says.

Testing the Brazuca

Goff, who is not employed by Adidas, worked with colleague Takeshi Asai, at the University of Tsukuba in Japan, to analyze the aerodynamic data of the new Brazuca ball before it hits the pitch.

Asai placed the ball on a rod in a 5-foot by 5-foot wind tunnel at speeds ranging from 16 to 78 mph.

“We were looking at just about any speed that you would likely see in the game of soccer — from just general kicks that are used in passing to really hard free kicks and really hard kicks by the goalkeepers down the pitch,” Goff says.

From there, Goff and Asai examined the drag on the ball.

“You stick your hand out the window when you’re driving and you feel a resistive force from the air; that’s the force we’re measuring on the ball when we put it in the wind tunnel,” he says. “As the speed changes, certain changes in that force take place that have dramatic effects on the flight of the ball.”

The Jabulani, Goff says, experienced a “drag crisis” — a transition in the type of air flow over the ball — during powerful kicks such as corner kicks and goal kicks.

Goff says players will notice differences between the flights of the two balls more with intermediate-speed kicks than with high-speed kicks, since the Brazuca’s drag crisis occurs at lower speeds than the Jabulani.

“For example, consider a kick from 20 yards out. If kicked at 67 mph, the two balls will have very similar trajectories. If kicked at 45 mph, the Jabulani will experience more drag than the Brazuca. In fact, the Brazuca will cross the plane of the goal about a yard higher than the Jabulani. So, the intermediate-speed kicks will be more noticeably different this time around,” Goff says. “The flight is a lot more stable, and that’s a big plus for the new ball.”

MLS teams have been using a ball based on the Brazuca in their 2014 season. The only difference is the color.

D.C. United midfielder Perry Kitchen says he’s noticed a definite difference in this year’s World Cup ball, compared to the Jabulani.

“I think it’s got more of a realistic flight. It doesn’t necessarily knuckle like [the Jabulani did],” Perry says.

As technologies and materials evolve, it’s expected for sports equipment to change too. But Goff suspects there are additional motives for redesigning the soccer ball every four years.

“The cynic and realist would say it’s just money. It generates a great deal of attention — research attention, sports fan interest — and these things are not cheap.”

Those looking to get their hands on the Brazuca, which was released to the public for purchase on April 15, can expect to pay around $160.

But will the price and improved technology guarantee a win?

When it comes down to playing and performance, D.C. United’s Kitchen says he doesn’t notice a major difference.

“A ball’s a ball, so it’s not anything that we haven’t seen before.”

h/t NPR

Adidas sent a Brazuca, equipped with six embedded cameras, around the world to collect videos, photos and stories of soccer leading up to the game:

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