(Transcript from SBS World News Radio)
Last World Cup it was the "beach ball", this World Cup, it's set to be the "keeper's ball".
Every four years, FIFA goes to great lengths to produce a new design of ball for the world game - and with each fresh model , there's usually fresh controversy.
But as Karen Ashford reports, this year's ball has been put through its paces by Australian researchers and it's come up a winner.
(Click on the audio tab above to hear the full report)
It's called the Brazuca.
And according to the predictions of Australian experts, it's going to result in fewer goals at this year's World Cup.
The Brazuca comprises six heavily dimpled panels, joined by a deep seam.
Adelaide University physicist Professor Derek Leinweber says wind tunnel tests coupled with computer modelling, shows this long deep seam means a smooth, stable ride.
"The thing that is critical for the aerodynamics of the ball is actually the depth of the seam and the length of the seam. And they've been very clever in have a long path for the seam around the ball. And this ball has only 6 panels and I think the panel is of interest to the players, because the idea is you have more predictability, more uniformity, so that when their foot contacts with the ball it becomes more reliable. But aerodynamically it's about the deep grooves."
The combination of those deep seams and rough dimples create a cushion of turbulent air that hugs the ball and somewhat paradoxically delivers a smoother trajectory.
The turbulence acts like a virtual layer of cotton wool, delivering the smooth ride - unlike the last World Cup ball, the Jabulani, whose smoother surface meant it slipped and slid unpredictably.
"Because it's aerodynamically rough, the ball becomes predictable. It means that the boundary layer of the air around the ball is in a turbulent mode, it very nicely covers the ball. When the ball slows down you will have a transition from this turbulent airflow which is good, to a laminar or smooth airflow which is bad. And in the process of that happening, weird things can happen, and that's where the Jabulani got into trouble. That transition from turbulent airflow hugging the ball to smooth airflow coming away from the ball happened at very high speeds - and it became dependent on the details of the surface. You could have one side of the ball perhaps tripping turbulence which would pull the ball to one side and so what happened when the Jabulani was coming towards the keeper it would be erratically moving and they really had a rough time figuring out where it was going to go . Now that transition happens in this ball (Brazuca) but it happens at very low speeds so it's not a problem - it becomes predictable."
Predictability makes the defenders task easier - meaning fewer goals.
Adelaide University PhD candidate Adrian Kiratidis says the Brazuca not just likely to be the goalkeeper's friend ...but Australia's friend too.
The Socceroos are renowned for their aerial tactics and use of headers - manoeuvres requiring certainty in trajectory.
"I think Australia traditionally likes a lot of headers, Tim Cahill for example is great in the air, and for a player who is headering the ball they definitely want something that's more predictable, so Brazuca will be a better ball. So in terms of Australia's tactics I would say the brazuca is a better ball for them."
Mr Kiratidis says for all its technological advances, the Brazuca's behaviour actually harks back to the old black and white ball.
"The Brazuca is very similar to a 32 panel ball, and hence the goalkeepers will prefer the Brazuca over the Jabulani. So I think it depends on what situation you're in, but all in all the Brazuca is a more predictable ball, which I think will give both the players and the goalkeepers a chance to really showcase their skill at this World Cup instead of concentrating on getting used to an unpredictable ball."
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