Why Are Tennis Balls Yellow

Tennis balls are the quintessential modern dog toy. My dog can sniff them out of roadside ditches, and nothing gives her as much joy as chasing after them in a wide open field. However, tennis balls are a special toy in our household, reserved for supervised playtime. This is because, while they are undeniably one of the most beloved dog toys out there, tennis balls can pose health risks for dogs. Choking Hazard My dog loves chomping on tennis balls until they pop. Dogs with powerful jaws like hers can easily break tennis balls in their mouths. This can lead to serious choking hazards. Sometimes, one-half of the tennis ball can get lodged in the back of their throats, blocking the airway. If this seems far-fetched, you may have heard that Oprah Winfrey’s Golden Retriever, Gracie, choked to death on a plastic ball. The ball itself is not the only choking risk. Some dogs enjoy shredding the yellow-green fuzz that surrounds the tennis ball. Eating this fuzz can lead to choking hazards and intestinal blockages that could require surgery. Dental Wear and Tear Choking hazards aside, tennis balls pose another risk: dental wear and tear. That green fuzz might seem soft, but tennis balls are designed to withstand tennis courts and rackets.

Dr. Thomas Chamberlain, a board-certified veterinary dental specialist, warns that the fuzz is actually quite abrasive, and accumulated dirt and sand increases the abrasive quality of the ball. As your dog chomps on a tennis ball, the fuzz acts like sandpaper, gradually wearing down her teeth in a process called “blunting.” This can eventually lead to dental problems such as exposed tooth pulp and difficulty chewing. How to Play With Tennis Balls Safely These risks are serious, but you don’t have to throw out all of your dog’s tennis balls. Instead, make sure that your dog only has access to his tennis balls during supervised play sessions. This is especially important for dogs that like to chew on tennis balls, as they are the most at risk for choking and dental wear. There are a few other things you can do to ensure that your dog plays with tennis balls as safely as possible.

Work with your dog to make sure that tennis balls never become part of a game of “keep away.” You need to know that you can get the tennis ball away from your dog quickly if it becomes dangerous, and the “drop it” command is also a useful command to have in your arsenal in case your dog puts something else in his mouth, for example a bone or piece of dangerous trash. Dr. Marty Becker, a veterinarian writing for VetStreet.com, advises keeping more than one tennis ball on hand for a continuous game of fetch, which can help keep your dog in shape, but cautions against allowing dogs access to more than one tennis ball at at a time. Dogs that pick up multiple tennis balls could get the ball at the back of their throats lodged dangerously. If your dog can’t handle tennis balls without chomping obsessively, you may want to consider an alternative toy. A rubber ball, especially one designed for powerful chewers, makes an excellent tennis ball substitute, without some of the risks. All in all, tennis balls can be a fun part of your daily routine, as long as you are aware of the potential risks and take the necessary steps to prevent accidents.

Tennis Balls - Walmart.comIt’s common to see her racing out the door at lunch time to head to a tennis practice with her team affectionately known as the “Smash Girls.” Watching our CEO maintain health—physical and mental—by slamming fuzzy, fluorescent balls across the tennis court made us wonder about the science of tennis balls. First of all, why are tennis balls fuzzy? The simple answer has to do with the aerodynamics of the ball. When the bright yellow felt that covers a tennis ball is fluffed up, even slightly, it has an effect on the ball’s speed as it flies through the air and over the net. Not that there are many folks out there who would be able to tell much of a difference when watching the next US Open. After all, when Serena Williams serves a ball at 122 miles per hour, it can be difficult to imagine any amount of fuzz capable of slowing the ball down. The fuzz on the ball can also impact the path of the ball as it soars toward your opponent. You could hit the ball with just the right kind of spin and think getting your point is inevitable. But, what if some stray fuzz catches the wind? That slight change may just cause the ball to veer off course, giving the other player the opening he or she needs to send the ball right back to you. Have you ever noticed how the pros will sometimes examine several tennis balls before settling on the one they ultimately serve across the court? They are looking for the perfect ball. The one ball whose fuzz is lying as flat and as close to the surface of the ball as possible. The tennis ball has come quite far in its long history. Modern tennis balls have always been made of rubber but, historically, the balls were made from leather, moss, human hair, or even sheep guts. Picture yourself arriving at the tennis court with a freshly opened can of sheep gut tennis balls. Makes you thankful for advances in modern sport science, doesn’t it? Understanding why tennis balls are fuzzy is one thing but understanding why they bounce is another.

One aspect is entropy and another is the chemical composition of the ball. The chemical composition of a ball establishes the elasticity, which determines the ball’s ability to retain energy when deformed and subsequently influences the bounce. With increased elasticity more energy is retained in the rubber and recovered in the bounce. Different rubber materials retain different amounts of energy–all rubber is not created equal. Therefore, the bounce-ability of a tennis ball is largely controlled by the molecular structure of the rubber. And even though our modern tennis balls have always been made of rubber, the bright yellow fuzz was not always a commonplace look. Early on, tennis players would stitch flannel around the outside of the rubber core. And, depending on the look of the court on which the players played, the balls were typically either black or white in color.

This leads us to another question: why are tennis balls a bright, fluorescent yellow? Again, we have another simple answer. Because of television. In 1972, the International Tennis Federation introduced yellow tennis balls because studies showed the yellow balls were easier to see during televised tennis tournaments. Not everyone was on board with this change, however. Wimbledon continued to utilize the traditional white tennis ball until 1986. So, the next time you play a game of tennis, or even watch a couple of pros go at it on TV, see if you can notice if there is a difference between a brand new ball being used versus one that has seen its share of match points. And remember to be grateful for that little yellow ball flying across your screen. If it was still white, there may not be much to watch.