Adidas Jabulani

It was consequently developed into the Adidas Tango 12 series of footballs. The Jabulani had a mixed reception during the World Cup due to its unusual flight pattern. The NASA Ames Research Center studied its performance and compared it to the +Teamgeist Berlin (used in the 2006 World Cup) and found it had a noticeable "knuckleball" effect. Jabulani, meaning "be happy!" in Zulu, is the imperative plural form of the verb zu "to be happy". Its design was much maligned by players at the World Cup, and production ceased after two years.

• Title — Adidas Jabulani • Type — Association football • Inventor — Adidas • Manufacturer — Adidas

The ball was constructed consisting of eight (down from 14 in the 2006 World Cup) thermally bonded, three-dimensional panels. These then were spherically moulded from ethylene-vinyl acetate (EVA) and thermoplastic polyurethanes (TPU). The surface of the ball was textured with grooves, a technology developed by Adidas called "Grip 'n' Groove" that was intended to improve the ball's aerodynamics. The design had received considerable academic input, being developed in partnership with researchers from Loughborough University, United Kingdom.

• FIFA-approved standard — Jabulani measurements • Circumference — 68.5–69.5 cm — 69.0 ± 0.2 cm • Diameter — ≤ 1.5% difference — ≤ 1.0% difference • Water absorption — ≤ 10% weight increase — ~ 0% weight increase • Weight — 420–445 g — 440 ± 0.2 g • Uniform rebound test — ≤ 10 cm — ≤ 6 cm • Loss of pressure — ≤ 20% — ≤ 10%

The ball had four triangular design elements on a white background. The number 11 was prominent in the use of the ball, as 11 different colours were used; representing the 11 starting players in a football squad, the 11 official languages of South Africa, and the 11 South African communities. The Jabulani Angola, used at the 2010 African Cup of Nations in Angola, was coloured to represent the yellow, red and black of the host nation's flag. An orange version is available for winter games and a yellow version for indoor games. A gold colour version, called the Jo'bulani, was used for the 2010 FIFA World Cup Final. Its name is a portmanteau of "Jabulani" and "Jo'burg", a common nickname for Johannesburg, the match venue. The gold colouring of the ball mirrored the colour of the FIFA World Cup Trophy and also echoed another of Johannesburg's nicknames: "the City of Gold". The Jo'bulani ball was the second World Cup Final ball to be produced, the first time being the +Teamgeist Berlin for the 2006 FIFA World Cup.

The balls were made in China, using latex bladders from Enkay Rubber Group, India, thermoplastic polyurethane-elastomer from Taiwan, ethylene vinyl acetate, isotropic polyester/cotton fabric, glue and ink from China.

• Illustration — Carlos Alberto Parreira and Franz Beckenbauer presenting the 2010 FIFA World Cup semi-final match balls • Illustration — The Adidas SpeedCell for the 2011 FIFA Women's World Cup It was announced on 4 December 2009 that the Jabulani was to be the official match ball of the 2010 FIFA World Cup held in South Africa. The ball was also used as the match ball for the 2009 FIFA Club World Cup in the United Arab Emirates, and a special version of the ball, the Jabulani Angola, was the match ball of the 2010 African Cup of Nations. This ball was also used in the 2010 Clausura Tournament of Argentina as well as the 2010 MLS season and 2011 MLS season in the United States and Canada in the league's colours of blue and green. In Europe domestic leagues, it was used in the 2010–11 Bundesliga in the league signature colours of red and white, known as the Torfabrik ("Goal Factory"), and in the 2010–11 Primeira Liga, coloured in white. UEFA used the ball in the Super Cup and the Europa League with respective official match ball colours and design. A new version of the ball called the "SpeedCell" was manufactured for the 2010 FIFA Club World Cup and the 2011 FIFA Women's World Cup. It featured the same technology as the Jabulani, but in a blue color scheme. The ball was used in the J.League during the 2010 and 2011 seasons.

A number of Adidas-sponsored players responded favourably to the ball. Álvaro Arbeloa, commented that, "It's round, like always." Brazilian midfielder Kaká said, "For me, contact with the ball is all-important, and that's just great with this ball." English midfielder Frank Lampard called it "a very strong ball, true to hit". German midfielder Michael Ballack said it was "fantastic; the ball does exactly what I want it to". Uruguayan forward Diego Forlán, who tied for the Golden Ball, studied the ball in the months before the tournament, explaining he had "lot of practice, a lot of training and again a lot of practice. I got lucky and [the Jabulani] behaved very well back then. And we got along great." Adidas has said that the ball had been used since January 2010, and that most feedback from players had been positive. A spokesperson said the company was "surprised" by the negative reaction to the ball, and highlighted that the frequent pre-tournament criticism a new ball receives inevitably dies down as the tournament proceeds.

On 27 June 2010, FIFA acknowledged concerns about the ball, but also said that they would not act on the problem until after the tournament. According to secretary general Jérôme Valcke, FIFA will discuss the matter with coaches and teams after the World Cup, then meet with the manufacturer Adidas.

NASA scientists at the Fluid Mechanics Laboratory at NASA's Ames Research Center, Moffett Field, California tested the performance of the Jabulani design against the earlier 2006 design which had also received criticism of its behaviour in flight. In discussing the mechanics of the balls Rabi Mehta, an aerospace engineer at NASA Ames, described the unpredictable behaviour as "a knuckle-ball effect". He explained that when a seamed ball is struck with little spin it experiences asymmetrical air flow effects as a result of the air close to the surface being affected by those seams. This causes unpredictable movement akin to the knuckleball pitch in baseball. The speed of the ball is the main factor in its behaviour, but it is also affected by altitude and wind. Where older designs of footballs have a knuckling effect at speeds closer to 30 mph, Mehta predicted that the Jabulani would experience the knuckling effect at the higher speed of 45 - due to its smoother surface. Free-kicks in the goal area tend to be kicked at this speed, making the knuckling effect of the Jabulani relevant to the game.