RIO DE JANEIRO – It's gotta be the ball.
The number and quality of goals in this year's World Cup is remarkable bordering on incredible, and there have been plenty of theories as to why. The simplest may be the coolest: the mighty Brazuca.
The South Africa World Cup produced 77 goals in the first 36 matches. This tournament, with its "Brazuca" ball, has produced 108 in the same amount of games. That's more than a 40 percent increase. No offense to the greatest soccer players in the world, but they are not 40 percent better at their sport than they were four years ago.
"There's got to be something with the ball," said Rabindra Mehta, a soccer fan who just so happens to also be an aerospace engineer at NASA in California.
Here's what he means: World Cup soccer balls got progressively smoother over the course of several years in the early 2000s, which makes sense on one level. Smoother seems better. But it's actually worse.
A smoother ball can be more difficult to spin, for the same reason that a golf ball is easier to spin because it has dimples. There's also something called the Magnus effect, which causes a spinning ball to curve through the air (hence "Bend it like Beckham").
The Jabulani that was used in South Africa was smoother than this one, and it got complaints from players. This ball has longer and deeper seams, and it also has what Mehta calls "pimples" that make the surface rougher.
The combination of the seams and the pimples allows more hook to the arc in flight, and the results have been pretty to watch. Just look at the replay of Cristiano Ronaldo's cross on Sunday night against the Americans, or (if that footage gives you hives) Lionel Messi's last-minute left-footed strike against Iran on Saturday. The arc of the ball in flight is majestic. And quite effective.
"It's a lot easier to impart spin on this one than the 2010 and particularly the 2006," Mehta said. "Can that affect scoring? The answer is perhaps yes. It's hard to discount the ball when the aerodynamic factor has changed significantly over four years."
[Gallery: Evolution of the World Cup ball]
It's not just the spin, either.
Mehta didn't test the Brazuca, but he did have access to results from a wind tunnel experiment on the ball. The data was eye-catching.
"When you measure the drag on the ball," he said, "when it's flying through the air, the wind tunnel data shows that between about 30 mph and 50 mph, the drag on the Brazuca ball is lower. Significantly lower. So if a ball is kicked at 40 mph, it will fly faster."
So according to a NASA scientist – and who are we to argue with him? – the Brazuca flies faster at certain speeds and curls through the air more than its predecessors. It's not a long leap from there to higher scoring.
Mehta suggests there may be a psychological effect as well: Players who are more comfortable with this ball may be more eager to strike it. And goalies have an advantage as well: a ball with longer and deeper seams is easier to grab – like a baseball with its curved seams.
It's possible the scoring will drop once we get into the knockout stage, but it's unlikely the scoring will drop 40 percent. Mehta says "it would be foolish to discard the possibility" that the ball is not a factor in what we're seeing.
Even if it's not a factor, or less of a factor than it seems, the focus on the ball has a nice residual effect: more attention on STEM, or Science, Technology, Engineering and Math. There's a huge movement to get kids interested in STEM, and soccer is a perfect way to do it.
"Over the years, we've found, no kidding, that when it comes to aerodynamics, sports balls are something kids can relate to," Mehta said. "They're keen and watch intently when we show them how a curveball curves. You can see their eyes glow. This is exactly how to get kids involved in STEM."
So maybe the explosion of interest in the World Cup back in the States will help bequeath a generation of children who follow a certain pursuit more ardently than any other in American history.
More World Cup coverage:
- Sports & Recreation
- World Cup 2014