Why Are Tennis Balls Sealed? 7+ Interesting Reasons

why are tennis balls sealed?

Have you ever stopped to wonder why tennis balls are sealed? Have you ever bought a can of tennis balls? Do you ever think about why they are in air-tight containers? What is the reason for sealing them in cans?

It seems like a strange thing to do, especially when the average person doesn’t think about it too much. But if you take a closer look at the construction of a tennis ball, it actually makes sense! Keep reading to learn more about why tennis balls are sealed and how it affects their performance.

You’ve probably never given much thought to why tennis balls are sealed in those plastic containers, but it’s an interesting question. After all, there’s no real reason for them to be airtight. What’s the deal? Turns out, there’s a good reason for it – and it has to do with the way tennis balls are made.

Reasons Behind Sealing Of Tennis Balls

Reasons Behind Sealing Of Tennis Balls

This article typically includes the reasons behind the sealing of tennis balls in cans especially from the scientific point of view.  But before revealing the reasons let us have a look at how tennis balls are made.

Construction Of Tennis Balls

Tennis balls are constructed almost entirely of rubber, with two pieces of round felt sewn together to form the ball’s core. The felt is necessary because it provides bulk while limiting rotational inertia which can cause an erratic bounce.

Hermetic Sealing

Have you ever wondered after hearing the pop sound every time whenever you open the can of tennis balls? This is because a pack of three tennis balls is sealed in hermetically or air tight cans which is pressurized and explodes on opening producing a sound you usually hear on opening a beverage tin. This hermetic sealing is done to prevent the air from escaping and to keep the tennis balls maintained with the perfect bounce to play.

Loss of Air

An air tight container usually contains three tennis balls. Sealing them in cans is the main purpose for their better performance. A certain amount of pressure is what they need to maintain their function and performance. Opening the tennis balls result in the loss of pressure and air from the very next moment. ln order to prevent deflating of the balls, they are sealed with a pressure of about fifteen pounds. Sealing them with the mentioned pressure prevents the tennis balls from getting deflated or losing the air till they reach the customer’s hand who open the can to take out the tennis ball to play.

Keeping in Air Tight Container

Tennis balls are sealed in air tight containers in order to maintain the specific pressure inside the balls which is essential for their overall better performance. Every tennis ball loses a very little amount of air when it gets hit across the net. This microscopic amount of air becomes visible within a few hours of heavy playing as the amount of leakage reaches high. Therefore, it is recommended by the professionals to break the seal just when the match is about to start.

One Way Sealing

A tennis ball differs from basketball and volleyball in the way that the pressure in tennis ball once lost can not be pumped back. There is only one-way route for the tennis ball. Once the ball is deflated and became dead, you have no other choice rather than to replace it with the pressurized new tennis ball. You can not play much comfortably with the dead ball as compared to the new and sealed tennis ball. The bouncing of the ball is badly effected once the seal is lost and air starts escaping from it. The sealing tends to preserve the goodness and liveliness of the tennis balls.

Improper Sealing

If tennis balls are not properly sealed, the result is deflation of them right after they are taken out of the can. These type of tennis balls are going to help you in playing tennis as you are not able to play with deflated and dead tennis balls, but they are helpful other than tennis as your dog will love to play with it and you may use these deflated balls for interior decorations and DIY crafts.

Lack of Equilibrium

Tennis balls are hollow inside and are sold in air tight cans. This is done to maintain an adequate pressure which is necessary for the perfect bounce and overall better performance of tennis balls. After opening the lid of this air tight can, the air which is entrapped starts diffusing outside due to the difference in concentration of pressure inside and outside. The pressure inside the ball is quite higher as compared to surrounding environment therefore, the air starts to escape. A lack of equilibrium is being observed between inside and outside pressure of the ball which enables the inside air to move out. The basic purpose of sealing is to prevent this diffusion till the pack is not opened. And further this sealing is proved to slow down the rate of transfer of air from tennis balls after the can is opened.

Pressureless Tennis Balls

Both of the tennis balls, the normal ones used in matches and the pressureless tennis balls are sealed. Provided with a hard and thick rubber outside, the pressureless tennis balls are not used for matches, but for practice sessions as they are heavier than normal, but do not flatten so quickly. Although there is no need of such pressure in the later type for bouncing consistently, but they need the seal to perform well.

Opening The Air Tight Can of Tennis Balls

Always go for the lively, new and sealed tennis balls to enjoy your play. Think before opening any can of tennis balls as there is no way of getting back. As soon as you have opened the can, the air will start leaking slowly. Go for opening the air tight can right before the match or practice to avail the best sealing feature of your tennis ball and to get the most enjoyment out of it.

The Dull Sound from Tennis Ball

The dull thud sound arising from the dead ball when a contact is made between the ball and the racquet is a symbol that the sealing of your tennis ball is effected badly and it needs to be changed as soon as possible. Proper sealing of the tennis balls ensures a typical bounce voice when the ball comes in contact with the racquet. For an effective functioning and a proper voice, they need to be sealed with great efficiency. Sealing plays a vital role in maintaining an overall perfect performance of the tennis balls.

Bounce of the Tennis Ball

If your tennis ball is not bouncing as effectively as it does, perhaps it is one of symbol that the sealing of your tennis ball is somewhat effected from the manufacturer. You need to replace it going to the shop where you have purchased it. Almost every tennis ball is sealed hermetically in order to keep it functional by keeping the air inside the shell of ball and prevent it from escaping. This makes the tennis ball lighter in weight and perfect to bounce.

Role of Tennis Balls

In every sport, there is not only the need of the player to be expert, but also the sport equipment to be perfectly designed and made. Whether you are a pro at tennis or you are a beginner, if the tennis ball is not perfectly sealed, you will never be able to play some mighty shots. The sealing of tennis balls is one the basic requirement of the game as it preserves the original bounce and liveliness of tennis balls. So, there is a great need for sealing the tennis balls in air tight cans.

Tennis Express

According to Tennis Express, a new tennis ball for average club players has the ability to maintain its bounce up to two weeks. But in professional games, there is need for changing the ball after every nine games to provide uniform bounce during the match. The whole story of tennis revolves around the ball bounce and the bounce is dependent upon the sealing. Consequently, the sealing in a tennis ball is done to maintain the proper bounce and better performance of the tennis ball.

Why are tennis balls vacuum sealed?

Pressurized balls are designed to maintain their pressure by keeping the air inside a tightly sealed container. As with all things, nature tries its best to get back into equilibrium and over time leaks will start seeping out of these containers because they’re not as efficient at maintaining balance like manufacturers initially hoped for 14-16 lbs in weight requirement per ball needed before doing any damage or killing bacteria (of course if harmful microbes were present).

Once opened there may be less than 15lbs left within; this lower external pressure around makes more room where gas can escape.

How long do tennis balls last in a sealed can?

You might be surprised to know that a sealed or unopened can of pressurized tennis balls won’t last forever. In fact, an unopened one will usually last around 2 years if left untouched in nice conditions- the pressure in these things slowly leaks out over time through micro leaks in packaging 

and even then they only have so much life before their rubber starts depleting.

How do they get air in tennis balls?

  1. Wilson’s first step is to make the rubber shell of the tennis ball. The rubber in Wilson balls comes from Thailand’s rubber trees. Thinned, heated, and sliced into pieces is the rubber compound.
  2. The rubber compound is molded into half-shells after being sliced. The molds are exposed to extreme heat and pressure in order to solidify the shells.
  3. The half-shells’ seams are polished and covered with adhesive.
  4. The shells are pressed in a hydraulic press, which is pressurized at 18 psi. The pressurized air is trapped inside as the shells are molded into a tennis ball core.
  5. After the shells have cured, they’re cooled to at least 127 degrees Fahrenheit to keep the core from exploding. Internal pressure reaches 15 psi when the core is cool enough.
  6. The interior felt is then applied to the core, which I won’t go into since this isn’t what we’re concerned about.
  7. By the conclusion of the procedure, the internal pressure is 12 to 14 psi. The cans get pressurized by 2 psi more than the balls since they contain extra air.

How do you make tennis balls last longer?

Tennis Ball Savers is a great way to keep your balls bouncing. I’ve used them for years and they work well at preserving the bounce of three tennis balls, or even just one ball in an emergency situation! Place it upright on any flat surface with some space underneath so that air can escape while pressurizing within – this will help minimize damage if there is pressure buildup as seen before when playing all day long (which I wouldn’t recommend).

A great tip to keeping your balls fresh is to leave them in the shade or indoors, out of direct sunlight – this will help prevent sun damage.

Why are there three tennis balls in a can?

The three balls that are in a can of pressurized tennis balls is merely for convenience and to make things easier. It allows the same cans to be used for all manner of different sized balls, whether it be beginner tennis ball sets or junior sets with their smaller ball circumference, the same air pressure cans can be used.

3 is a compact number and is sufficient for playing a set with a friend, having more than one ball to serve with, etc.

Final Thoughts

Tennis ball manufacturers seal the balls because it helps keep the tennis balls’ bounce consistent.  It also helps to increase friction with other objects.

This reduces slippage and improves performance of the ball in general, which means players will have an easier time using them during a game without worrying about any negative effects on their gameplay. If you’re wondering if there’s another reason for sealing these balls, then don’t worry; this is all you need to know.

If you want to use a sealed or unsealed tennis ball for your game, make sure you know what kind of surface and playing conditions are best suited for that type of ball.

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