I know the title of this article is pretty childish. But frankly, did you ever asked that question yourself? The answer is clear in the case of pressurized tennis balls, but what is inside of pressureless tennis balls? I decided to find it out.
What is inside pressurized tennis ball?
Pressurized tennis balls are the most common tennis balls used. They have hollow rubber core filled with air (pressurized air). So I need just a normal knife to cut it. See the video below:
The cut was quick and easy. And I found out what we all already know. There is nothing inside the pressurized tennis balls. Just the pressurized air.
What is inside pressureless tennis ball?
To find out what is inside pressureless tennis ball was a much tougher task. Pressureless tennis balls are solid inside and the rubber around is much stronger. It was impossible to make a cut just with a knife when holding the ball with a hand as I did with the pressurized tennis ball. I needed clamps and hand saw to cut into the pressureless tennis ball. See the video below:
There was a white smooth powder inside. The white powder is essentially micro cells holding the pressurized air. There should be around 700 million micro cells in every Tretorn X tennis balls (according to manufacturer), but I did not count them.
Now you all know what is the secret behind pressureless tennis balls. Why they do not lose the bounce, do not flatten at all and tennis ball machines like them. More about pressureless tennis balls can be found here.