Evolution of the Tennis Ball
Just as tennis is different from jeu de paume, tennis balls have also come a long way to become the familiar yellow fuzz things we are all so familiar with today. When it first started out, they were made of leather or animal intestines filled with earth, sawdust, sand, chalk, human hair, horsehair, or wool, and tied with rope. In 1480CE, however, the different varieties started to become regulated in France when King Louis XI only allowed the balls to be made of the best quality of wool and leather. The varieties kept on, however, in the Scotland where people were filling goat and sheep stomachs with wool, human hair, or putty stuffing, and tied it with a piece of rope to create the desired round shape. Later, these stuffed stomachs were wrapped in wool strips, tied by string, and then covered with a white fabric over the top to help with the game.
The tennis ball has become more like the modern ball when Charles Goodyear invented the vulcanization process of rubber in the1850s. At first, the rubber made the entirety of the ball, but later, people discovered that adding felt around the rubber made it better, and then even later, found out that hollowing the rubber while still adding the flannel was still better for more exciting game play. This is when the clover method was developed.
With the clover method, a sheet of rubber is stamped into the shape of a three-leaf clover, sewn into a circular shape, and then sewn over with felt. Now, we still use hollowed rubber, but we create two half-spheres and add pressurized gas (either nitrogen or just air) before putting them together. The ball is then buffed, covered with glue, which is then covered with a felt made of nylon or wool, and then heated to make everything stick and seal together.
This isn’t where the development of the tennis ball ended, however. It had a cosmetic touch-up and dyed its felt a bright yellow so that viewers could see it more easily on television. There are also still, different types of balls for various purposes.
Types of Tennis balls:
Pressure-less: solid cores and last longer than pressurized balls
Don’t lose bounce easily, but felt wears off faster
Come in nets or bags
Pressurized: hollow core filled with air/ nitrogen
Hermetically sealed and come in tin cans/ plastic tubes of three or four
Once can is open, balls start to lose their bounce
When brand new, bounce higher than pressureless balls
Used at all ATP and WTA events
Regular duty: for indoor and clay courts
Extra duty: for grass/ concrete courts
High altitude: used in high altitude regions where regular balls would have greater bounce
In order to create a fair playing ground for everybody, however, the ITF has enforced to standardize the type of tennis balls being put in play during tournaments; each ball is placed under various tests to ensure it can perform in any circumstance.
Diameter 2.5-2.7 inches/ 6.35-6.86 cm
Rebound height between 135-147cm
All balls are tested in the following environments:
Temperature: 20 degrees Celsius, 68 degrees Fahrenheit
Atmospheric pressure: 102 kPA
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