By Andrew Nusca
Posting in Science
Adidas says its 2010 World Cup soccer ball, Jabulani, is the most accurate it's ever produced. Here's how it's engineered.
Every four years, teams fielded by nations around the globe meet to battle it out on the soccer pitch.
And every four years, the fruits of sports innovation and engineering appear in the form of the official World Cup soccer ball.
Let's see how it's made, shall we?
Most folks know the soccer ball as a 32-panel, black and white affair. But with a little engineering, the ball can be altered in how it feels on the foot and how predictably it travels in the air.
Adidas' Teamgeist ball achieved accuracy with a reduction in the number of panels, from 32 to 12, and a process that thermally bonded them together to eliminate the inconsistencies of stitching and offer the ability for form the outer panels in three dimensions (versus bending flat panels into a spherical shape).
In the same vein, Jabulani uses just eight panels made of EVA and TPU. With fewer seams, Adidas says Jabulani provides a 70 percent larger striking surface.
Players said the 2006 Teamgeist ball was favorable for strikers -- the players at the front that often score goals -- but unfavorable for goalkeepers, because the ball's lack of rotation in the air made its trajectory difficult to judge.
To address this, Adidas gave the Jabulani ball "aero grooves," or indentations in a specific pattern that run along the panels to help give the ball consistent trajectory. Small, raised "microtexture" indentations also help give the player more control.
Adidas says that internal robotic kicking and wind tunnel testing at Loughborough University in England, as well as at its own lab in Germany, show that Jabulani is the company's most accurate ball. (I sure hope so -- Jabulani is priced at $150.)
For FIFA approval, the ball must meet the following metrics:
- Circumference: 68.5 to 69.5cm (Jabulani: 69.0 +/- 0.2)
- Roundness, or diameter: Maximum 1.5 percent deviation (Jabulani: max 1.0 percent difference)
- Water Absorption: After the ball is pressed and rotated in water 250 times, maximum 10 percent weight increase. (Jabulani: 0 percent weight increase)
- Weight: 420 to 445 grams (Jabulani: 440 +/- 0.2 grams)
- Uniform Rebound: The ball is dropped ten times onto a steel plate from a height of two meters. The difference from the lowest to the highest bounce can be no more than 10 cm. (Jabulani's range: 143 to 149 cm)
- Loss of Air Pressure, after three days of inflation : 20 percent loss, maximum (Jabulani: 10 percent maximum loss)
Here's a video of the Jabulani manufacturing process:
Dec 7, 2009