Thursday, August 11, 2022 Aug 11, 2022
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Weird Science

A new synthetic ball has debuted in the NBA. Scientists at UT Arlington used a vacuum cleaner to test it.
By Eric Celeste |
BOUNCE HOUSE: Drs. James Horwitz (right) and Kaushik De, two of the researchers at UTA, found that players might have valid complaints about the NBA’s new ball.
photography by Elizabeth Lavin

Terdema Ussery, team president of the Dallas Mavericks, needed help with a ball problem. After 60 years, the NBA this season heaved its traditional leather ball in favor of a synthetic microfiber composite model. The league made the change for consistency’s sake. NBA games had been played with slightly used, or “conditioned,” leather balls. This led to an annoyingly subjective pre-game ritual wherein referees and players would argue over which ball felt and bounced best. Also, because leather is absorbent, balls could gain nearly 12 percent of their weight in sweat during games. The new synthetic ball, which took Spalding eight years to develop, would remedy that.

But in early October, Ussery had been hearing complaints from around the league, as well as from his own players, about the new ball. Players such as Shaquille O’Neal and Steve Nash thought the new ball was dead, bounced erratically, and was, like the Bon Jovi album, slippery when wet.

So Ussery decided to collect some independent data. He rang the University of Texas at Arlington physics department. Dr. James Horwitz, the department’s chairman, says his assistant bolted into his office after taking the call. “She was pretty excited,” Horwitz says. “We all knew it would be fun. We knew it would be high-profile. We knew it would generate a lot of interest.” He smiles. “And we were right.”

Not long after Ussery’s call, Horwitz went to a Mavericks pre-season game to get a fuller understanding of the debate. There were those fans who said the players were whining, because professional athletes should be able to adjust easily. Even Dallas Mavericks coach Avery Johnson, perhaps trying to make sure his team didn’t use the new ball as an excuse for poor play, sided with the shut-up-and-play crowd. “I think it’s mental, also,” he said one week into the season. “Once they get used to it, they’re professionals. A lot of these guys, they’re so good, they can shoot a football.”

This ignored a paradox that Mavericks owner Mark Cuban (who declined further comment) alluded to on his blog in a series of posts about the ball and its testing at UTA: for professionals, the smallest deviation can affect play. To you, for instance, one golf ball is probably as good as the next. But Tiger Woods can detect seemingly imperceptible differences, even though he’s only “feeling” the ball through his club. Example: when Woods was testing Nike One balls, the company’s director of product development slipped in a rival-brand ball just to see what would happen. Before his chip shot hit the green, Woods stood up and asked, “What did you give me there?”

So who was right, Johnson or Cuban? Both, actually.

“Pro basketball players have spent huge amounts of time and concentrated effort honing their skills with the old NBA basketball,” says John Fontanella, a physics professor at the U.S. Naval Academy and author of the new book The Physics of Basketball. “Consequently, they will be more sensitive to differences in the new basketball than an amateur, and their skills are more highly developed so that they have more to change. On the other hand, the pros are gifted athletes. It is easier for them to adjust.”

Then why the complaints? Fontanella, who doesn’t like the new ball, says, “Unfortunately, there are factors involved that make it impossible for anyone to adjust.”

It was up to the scientists in white lab coats at UTA to determine just what those factors were. They began by measuring the balls’ coefficient of restitution, or bounciness. They dropped all three types of ball (leather ball conditioned by Mavericks players, new leather, and new synthetic) under an ultrasound sensor.

Two problems emerged. The first: it’s tough to drop a ball in a consistent manner. The solution: a vacuum cleaner with a hose attached, the sucking power of which held the ball until the machine was turned off, which allowed for a consistent, albeit loud, measurement. The scientists could then objectively see that the synthetic ball was “deader” than the conditioned leather ball and did not bounce as high.

The second problem: the scientists could only get a bounce or two of measurement on the synthetic ball, but four or more on the leather one. Why?

Because for this test, the ultrasound sensor was set to a narrow range of angular resolution. Think of a flashlight beam as opposed to that of a car headlight. The new synthetic ball was bouncing erratically, bounding out of the sensor’s narrow range.

So the UTA team set up two beams to test horizontal deviation, or how erratically the balls bounced. They found that the leather ball had a much truer bounce than the new synthetic ball.

Through the first few weeks of the season, the new ball’s deadness and erratic bounce have been confirmed anecdotally. The most high-profile example was Vince Carter’s 3-point shot to send the New Jersey Nets’ game against the Washington Wizards into overtime. The shot, flung from 26 feet away, hit the metal back of the rim that mores it to the backboard and flopped into the goal like “a waterlogged Nerf,” as one story put it. Would his shot have gone in with the leather ball? “If it would’ve hit like that?” Carter said after the game. “Heck no. No way.”

A dead ball actually helps scoring, because the shots are more likely to “die” on the rim and fall in. But as Cuban wrote after the Mavericks beat Nash’s Phoenix Suns for the team’s first win of the season, the new ball seemingly had Nash out of sorts. “Watching Nashie last night, I felt bad for him. … It just seemed last night that there were times he had to hesitate to make sure the ball was there before he could make the pass he wanted to make.”

The UTA team believed that this sort of dribbling problem, expressed by many players, could be due to the erratic horizontal deviation. “You can’t adjust to something that is imperfect,” says Dr. Kaushik De, who helped oversee the research at UTA. “You can only adjust to a difference that is consistent.”

Or is it because the ball is slippery? To test the new ball’s coefficient of friction (slipperiness), the UTA researchers attached small cut-out sections of the balls’ surface material to the bottom of a container holding the average weight of a basketball. Beneath the pieces of ball, they placed a sheet of silicon, the material that best approximates the characteristics of the human palm. Then they attached to the container a pulley-and-weight system that could measure how much force it took to cause the surface material to move or “slip.”

Spalding says the new ball’s coefficient of friction proved it wasn’t as slick as a leather ball. Which, the researchers found, is true only when the balls are dry. But in the NBA, playing with sweat-covered balls is a fact of life.

So the researchers added a drop of Visine or similar saline solution to test the balls’ characteristics when the surfaces were wet. The shift was dramatic. The synthetic ball became much slipperier.

This shouldn’t be a surprise. Spalding boasts that the synthetic ball doesn’t absorb water like the leather ball does (something the UTA team found true), so it won’t gain weight during a game. But that non-absorbency also means the sweat stays on the surface of the ball.

Spalding disagrees with Horwitz and the UTA team on this point. “Our coefficient of friction testing demonstrated that the new ball’s grip outperformed the leather ball’s grip in both wet and dry conditions, whether the balls were new or used,” says Ron LaLiberty, Spalding’s director of product development. He also says the company hasn’t heard complaints about bounce inconsistency.

Some of the data amassed during the first 100 games of the season support Spalding’s claim that the ball will not increase turnovers. As NBA statistical guru John Hollinger notes, the rate of players losing the ball or committing turnovers on passes is down or even from last season. However, scoring and shooting statistics do suggest the ball is considerably deader. That is one reason Cuban suggests more studies be done, even though he ultimately supports keeping the new ball. Not that the NBA seems to be entertaining a return to the old leather ball.

The irony is that the new synthetic ball is also leading to the same annoyingly subjective argument that the NBA sought to eliminate. In November, five minutes into a game between the New York Knicks and Cleveland Cavaliers, players stopped play and asked to have replaced what they thought was a dead ball. The refs shrugged, as if to say, “If that’s what you guys want, but they’re all the same.” Then they gave the players another new ball.