Did you know that the fuzz on the tennis balls makes the ball slow down and the game easier to watch?
Or did you know that the players choose the balls based on the fuzz?
This is a comprehensive guide to how the structure and fuzziness of a ball impact the game of tennis.
- How Tennis Balls Have Changed?
- But What Is the Fuzz?
- Too Much Fuzz Is Bad
- Players Check the Fuzz Before a Serve
- How Much Does the Ball Slow Down?
- Read More
How Tennis Balls Have Changed?
In the past, tennis balls were made by wrapping wool into a ball and covering it with leather or cloth to dampen its bounce. Without the outer wrapping, the ball would bounce around uncontrollably.
Nowadays, tennis balls are made from rubber. They are created by sticking two rubber half-shells together and filling them with compressed air to bounce.
But What Is the Fuzz?
Tennis balls are covered with fuzzy wool, nylon, and cotton material. This material is cut in a dumbbell shape and glued onto the ball, giving it those curvy seams.
This fuzzy layer called the nap, is crucial for how the ball plays in the game and is the most expensive part to make. In addition, the fuzzy layer is there to increase friction between the ball and the air. This will slow the ball down, making the game easier to play and spectate.
Too Much Fuzz Is Bad
When a tennis ball is in heavy use, the fuzz spreads radially. This increases the surface area, which in turn slows down the ball too much. This is one reason why in tournaments the players change the balls every 7-9th game (the other one being the depressurization of the balls).
Players Check the Fuzz Before a Serve
Have you noticed that before every serve, the player has 3-4 balls in their hands out of which they choose two? Here’s how they make the decision:
Smoother Ball for the 1st Serve
The first serve is supposed to be the hardest one for the returning player. Thus, the player wants to choose a ball with as little fuzz as possible. This is to reduce the air resistance and to be able to serve the ball as fast as possible.
More Fuzz for the 2nd Serve
For the second serve, one needs to maximize the spin to hit the service box with the highest probability. This is why the player chooses the fuzziest ball of the bunch for the second serve.
The more fuzz, the more air resistance, and the more impact it has on the spin. If the ball is less fuzzy, it won’t spin that much and will hit the target with less accuracy.
Here’s a good video that explains the physics of spin and curve balls. I watched this 12 years ago as a high-school student and absolutely loved it as a geek I was (and still am).
How Much Does the Ball Slow Down?
When a tennis ball is hit, it slows down because of these three things:
- Bounce
- The ball itself
- Fuzz
When a tennis ball is hit, it slows down to about one-third of its starting speed because of these three. So, a ball served at 150 mph would slow to around 50 mph. This is what actually makes it possible to return a serve. If it didn’t slow down this much, it would be impossible to return!
