The Making of a Tennis Ball continues with the object that keeps everything else in this series intact until the moment you need it: the can.
Every chapter so far has described something happening inside the ball — the core, the felt, the pressurisation, the bounce, the colour. The can is different. It’s not part of the ball at all, and yet without it, almost none of the rest would matter. A ball built exactly to specification, sealed at peak pressure, would start losing that pressure the moment it left the factory floor — unless something stopped the clock.
Stopping Time, Briefly
The can does exactly one job: it holds the balls inside it at the same pressure they were sealed at, so the gradual pressure loss described earlier in this series simply doesn’t happen — not until the seal is broken. That’s why an unopened can, sitting on a shelf for months, still produces balls that feel and bounce like new, while the same balls, once opened, begin fading within days of ordinary play.
This wasn’t always how balls were sold. Pressurised canning became standard only once manufacturers understood exactly how much of a ball’s performance depended on internal pressure — before that, balls were often sold loose, and simply played in whatever state they arrived.
What’s Actually Inside the Can
The can itself is pressurised to match the internal pressure of the balls it holds, which is precisely why that distinctive hiss on opening isn’t just theatre — it’s the moment the can’s atmosphere and the room’s atmosphere equalise, and the slow pressure loss inside each ball formally begins. From that point on, the countdown described across this entire series — core, felt, pressurisation, bounce — starts running in earnest.
Next in the series: The Test.
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