Maddie and I went up to the wall yesterday afternoon for 30 mins of wall drills. Funny thing, though. Her soccer balls were in our nice warm house. We pumped 'em up to the correct inflation pressure and headed out. It was kinda cold at the elementary school where we do wall drills. After about 30 minutes playing, Maddie says "Dad, this ball doesn't bounce very good."What's up with that? Well, we were experiencing a real world example of a basic law of gas physics called Charles' Law. Charle's Law says that at a constant volume, the pressure of a gas is directly correlated to temperature. Meaning that as a gas gets colder, the speed of the gas molecules slows down, reducing the impact of the molecules against the interior skin of the ball - the pressure drops and thus the ball goes a little flat.
Here's a practical tip - if you store your balls inside the house where it's warm, you might want to overinflate by a bit so that as the ball cools down outside, it drops into optimal inflation pressure.
We originally inflated Maddie's soccer balls to 7 psi. When we were done, they had cooled down to 6 psi. It works in reverse on a hot day.
A low pressure inflation gauge works well to keep your balls at optimal playing pressure. Why is that important? Because at the optimal inflation pressure, feel and flight of the ball are just right - which is what your kicking stroke needs to be calibrated to. Plus, your soccer ball will last longer. We bought ours online from Eurosport here. This gauge has a nice rubber housing to keep it from breaking. It's best feature, however, is a built-in pressure release button. You can overinflate just a tad and use the button to drop your pressure right smack dab where you like it.
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