For the past few weeks, journalists and pundits have espoused various theories as
to why so many goals have been scored in the 2014 World Cup. Is the
overall quality of the finishers better? Are teams not playing defense
like they used to? Is Brazil’s warm climate somehow helping matters?
All of these are possible, but the theorizers may have all been overlooking the obvious — the soccer ball.
In an interview with Nautilus
magazine, NASA aerodynamics engineer Rabindra Mehta claims that the
Adidas ball being used in the tournament — the Brazuca — is far more
predictable in its movements, benefiting the strikers.
In other words, the Brazuca is the exact opposite of the
balls Adidas used in the 2006 and 2010 tournaments. Those balls, the
Teamgeist and the Jabulani, were criticized at the time by numerous
players, who claimed the ball moved too erratically in the air.
According to Mehta, the science backed the complaints up.
"Every object has a boundary layer, which is basically a
thin layer of air very close to the surface of the object," Mehta said.
"On a soccer ball, it's just a millimeter or two thick. The boundary
layer eventually becomes turbulent at a critical speed.
"So, when a ball hits that critical speed, the boundary
layer gets energetic and gains momentum. The drag [behind the ball]
drops, causing the ball to 'knuckle'" — the ball's flight pattern
suddenly takes on a mind of its own."
The previous two balls, though scientifically very
advanced, were too smooth. They had so little drag that when hit at
speeds around 45-55 miles per hour (the exact range that strikers tend
to hit the balls), they would fly unpredictably.
With the Brazuca, Adidas wisely decided to bring back some
drag. These balls, like so many of the World Cup balls used in previous
decades, "knuckle" at the critical speed of 35 mph. When struck harder
than that, however, the Brazuca regains its ability to fly in a
predictable path.
The difference? In 2010, 145 goals, an average of 2.27 per
match, were scored in South Africa. With two games still to play in
Brazil, 167 goals have been scored, an average of 2.69 goals per match.
That's only four fewer goals than in the record-breaking 1998 tournament
in France, where the event was expanded to 64 games.
Unfortunately, within a few days from now, we'll never see
the Brazuca make another official appearance on the field. Adidas might
do well in four years' time to save money by adding some new colors to
the Brazuca and giving it a new, Russian-sounding name. They probably
won't get many complaints from the players — or the goal-hungry fans.
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