Wednesday, July 14th, 2010...5:47 pm

Jabulani math

Jump to Comments

Given the last blog entry detailed my input on the Sports Science piece on home runs, it seems only appropriate to give the details of how my connections with Sports Science started.  The week before the World Cup began, I was in NYC with my family. The trip combined work and fun activities in the city.  Suddenly, the media’s emails began.  Each email inquired about the mathematics of predicting the trajectory of soccer balls.  Why? The new Jabulani ball, designed by adidas for the 2010 World Cup, was the target of some players’ complaints about the ball’s unpredictability. This is the same ball that was touted as being the closest to being perfectly spherical to within one hundredth of an inch — that’s pretty round! The ball was also very smooth — so much so that grooves were added by the designers. With all this, how could such a ball be seen as more unpredictable than others? Such a question led to the emails sitting in my Inbox.

It was fun to field the calls. The reporters knew information that I didn’t. I got to think about the trajectory of soccer balls, which was a topic about which I wrote several expository articles including an article for the Mathematical Association of America’s Math Awareness Month.

Part of the humor of my help on this was related to where I was at the time. The show works on a short timeline to keep topics relevant. So, we agreed I would call on that day but I would call rather than receiving a call. My family was at Coney Island in New York. There was a bit of time where sandcastles were under construction and my wife turned to me and said, “Now. This is a good time to make the call. Enjoy. We’ll enjoy hearing how it went.” So, I walked up to the boardwalk and found a quiet spot. And there, I talked math, physics and soccer balls. I shared as much as I could…connecting the need for roughness to golf balls, discussing how hard it is to model such things, and mentioning different types of flow and their impact on a ball.

In the end, it appears that some of my comments were helpful. The producer often said, “This is very helpful. Just keep going.” I was pleased when the show aired to see some of the concepts make their way into the video–in very cool Sports Science fashion.

For students and professors of math who are reading, you can learn more details of modeling the path of a soccer ball using math with my Math Awareness Month article, Bending a Soccer Ball with Math. This would be material suitable for a math class and could motivate discussions on modeling trajectory and how difficult it can be to include assumptions of air resistance and the shape of the object.

How did this materialize into a Sports Science video? Check it out…

Leave a Reply