What gas is in tennis balls??

[Ronaldo]

Gamma ProTour Balls use Nitrogen.

[The Meat]

Just to put it out there.

P= Pressure
V= Volume
n= number of Moles in system
R= Gas constant (0.8026 or something)
T= Temperature

n= m/M
moles= mass/ Molar Mass(mass of all elements, e.g. N2=28 amu)

Also, adding to ricki's explanation of oxygen and nitrogen diffusion. Oxygen gas(O2) should diffuse slower than Nitrogen gas(N2) because the molecular weight of oxygen gas is more than Nitrogen gas. However Oxygen only makes a single bond with another oxygen, while Nitrogen makes a triple bond to another Nitrogen(to complete the octet rule(8 electrons surrounding one element)). So Oxygen is smaller than Nitrogen, making it diffuse slower.

[Ronaldo]

Can anyone explain the effect of storing tennis balls in a pressurized container with more than 14 psi? Like 30 psi

[coachrick]

Originally Posted by Ronaldo

Can anyone explain the effect of storing tennis balls in a pressurized container with more than 14 psi? Like 30 psi

In theory, over a long period of time, the pressures would seek balance--thus increasing the pressure inside the ball to match that of the container. Might take a heck of a long time ...and you'd have one LIVELY, non-conforming tennis ball!

[SystemicAnomaly]

Originally Posted by ricki

gas type and temp are variables, pure nitrogen should be theoretically most consistent.

O2 "permeates" approximately 3-4 times faster than does N2 through a typical rubber, as is used in tires, primarily
because O2 has a slightly smaller effective molecular size than does N2.

source: www.getnitrogen.org/pdf/graham.pdf

But the claim by rafazx10 really had nothing to do with how quickly a given gas permeates. The claim was that some gases expand faster than others with an increase in Temp. I'm pretty sure he was talking about a short term effect. I don't see anything in the ideal gas law equation that says the Pressure of one gas will be affected more by Temp than another. The bounce of a pressurized ball is due, in large part, to the internal pressure relative to the external pressure.

[ramos77]

Apparently Babolat balls are filled with Nadals farts, straight after he has a Paella...

[rafazx10]

It is because of the moisture in the air, which is not found on nitrogen.

[diggler]

I think it depends on how the balls are made.

I read somewhere that when some balls are made, a pellet is put inside when they join the 2 halves together. The pellet sublimates from solid to gas and hence creates gas pressure.

Other balls are just air filled.

[Ronaldo]

Originally Posted by diggler

I think it depends on how the balls are made.

I read somewhere that when some balls are made, a pellet is put inside when they join the 2 halves together. The pellet sublimates from solid to gas and hence creates gas pressure.

Other balls are just air filled.

So that is why some balls rattle when shaken

[The Meat]

Originally Posted by Ronaldo

So that is why some balls rattle when shaken

Sublimation is the phase shift from a solid form to a gaseous form due to a change of temperature or pressure above a certain point. So the solid isn't there anymore, a ball that rattle might be a dog toy

[Ronaldo]

Originally Posted by The Meat

Sublimation is the phase shift from a solid form to a gaseous form due to a change of temperature or pressure above a certain point. So the solid isn't there anymore, a ball that rattle might be a dog toy

Usually those balls are dogs.

[diggler]

I haven't had a rattler in years. Maybe they don't make them like that anymore.

[Nostradamus]

Originally Posted by coachrick

Ba-ZING-a!

Unless things have changed, it's ambient air in most balls. Gamma used to put nitrogen to slow the pressure loss, but I don't know if that's what they do currently.

i thin you are right. it is liquid nitrogen

[zorcy3]

I saw on Discovery or Learning channel, I think, that it is CO2 in most balls. The rubber is porous enough for O2 to pass easily. Regular air will pass back and forth as you pressurize it in a tank. Eventually, the harder to pass molecules, N2 and CO2, will not bother to go into the ball. This will take a faster charge, but die out before you are finished with practice. When you recharge, consider other gases. N2 is the best, CO2 is second and regular air is the fall back. Never use O2, it just bleeds back out too fast.

As far as what happens on the balls in a tank? At 14 PSI of CO2, they will stay at their normal hardness. If they stay long enough, some CO2 will get inside. At 30 PSI of CO2, It will charge faster. Maybe as fast as 3 days. It will push CO2 into the ball, not letting O2 out. If you let it sit for a week or 2, the O2 will come out on its own and it will have more CO2 in the ball.

If you don't have a tank, get one. They are great, unless you are some major player that kills the felt every time you open a new sleeve.

[mikeler]

Oh no, the OP finally got the answer he wanted in post #34. Wait for it...wait for it...

[Ronaldo]

Originally Posted by zorcy3

I saw on Discovery or Learning channel, I think, that it is CO2 in most balls. The rubber is porous enough for O2 to pass easily. Regular air will pass back and forth as you pressurize it in a tank. Eventually, the harder to pass molecules, N2 and CO2, will not bother to go into the ball. This will take a faster charge, but die out before you are finished with practice. When you recharge, consider other gases. N2 is the best, CO2 is second and regular air is the fall back. Never use O2, it just bleeds back out too fast.

As far as what happens on the balls in a tank? At 14 PSI of CO2, they will stay at their normal hardness. If they stay long enough, some CO2 will get inside. At 30 PSI of CO2, It will charge faster. Maybe as fast as 3 days. It will push CO2 into the ball, not letting O2 out. If you let it sit for a week or 2, the O2 will come out on its own and it will have more CO2 in the ball.

If you don't have a tank, get one. They are great, unless you are some major player that kills the felt every time you open a new sleeve.

Ty, never could recharge dead balls even after two weeks in my tank at 25-30 psi. Awesome sound though, unleashing the pressure.