Why Is There Fuzz on a Tennis Ball?

The fuzz on tennis balls is actually felt, a cloth made from matted fibers. The felt is bonded to the rubber compound of the ball, and is prepared to create the uniquely fuzzy surface.

Early tennis balls

Early tennis balls were made from leather stuffed with wool, or even hair-reinforced putty. The rising popularity of lawn tennis in Britain during the Victorian era led players to search for ways to improve the game. John Moyer Heathcote, an English tennis player, is credited with inventing the first cloth covering for the tennis ball. Although it is debatable as to whether Moyer knew why a cloth covering improved the performance of the ball, Moyer's influence over the emerging game of lawn tennis probably contributed to this new covering becoming standard.

What does the fuzz do?

The fuzz on a tennis ball is designed to reduce drag. Contrary to expectations, fuzzy or dimpled sports balls travel much further than smooth balls when hit. Another example of this is found in the dimpled surface of a golf ball. However, the fuzz on a tennis ball creates much more drag than a golf ball's surface.

Wind tunnel research

In a 2000 study at NASA's Ames Research Center, Dr. Rabi Mehta proved that the fuzz on tennis balls affects their flight much more than previously thought. Using NASA's wind tunnel, Dr. Mehta was able to demonstrate that the fuzz fibers were surprisingly effective at reducing wake. Smaller wakes mean lower drag, and less drag means further travel.

New balls please

The aerodynamic properties of tennis balls subtly alters over time, as the fuzz naturally wears down through the passage of play. This one of the main reasons why several new sets of balls are used during a competition match.

Early tennis balls were made from a variety of materials, but none of them would have had particularly good flight properties. Moyer's chance discovery resulted in a ball covering which has significantly improved the game of tennis.