chrischris
G.O.A.T.
My GF asked me a question last night that i was a bit at odds with .. 'whats inside the tennis balls'? i said i dunno.
What gas is in tennis balls??
- Thread starter chrischris
- Start date
coachrick
Hall of Fame
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.
chrischris
G.O.A.T.
WTF, noone knows ??? we all use them , yet no clues as to whats inside them .. no wonder we are losing out to the Chinese
LOL
LOL
The Meat
Hall of Fame
^This, the main compositions of air in the atmosphere
What I can definitely exclude out of the possible gases are: Neon, Hydrogen, and Helium. These three gases would leak out of the rubber walls faster.
My best guess if it were practical is methane gas, doesn't leak out as fast due to it being a molecule and not just an element so its larger. CH4 for those who want to know it's formula.
coachrick
Hall of Fame
WTF, noone knows ??? we all use them , yet no clues as to whats inside them .. no wonder we are losing out to the Chinese
The first clue was in post #3. As mentioned later, the composition is virtually nitrogen and oxygen...like the air we breathe. A 'pure' nitrogen use would slow pressure loss slightly and the balls could 'run' a little cooler like race car tires.
chrischris
G.O.A.T.
robbo1970
Hall of Fame
Actually its methane....don't ever cut one, people with think you farted.
Double bazinga.........I don't even care.
SystemicAnomaly
Bionic Poster
Yes, I believe that this is the correct answer. Nitrogen/Oxygen or regular air for most balls. The pressure (for pressurized balls) of a new ball can vary from one manufacturer (or model) to the next. I've seen pressures listed in the range from 1.6 to 1.8 atm (but I have seen some sources indicating only 1.2 atm for a pressurized ball). I believe that Gamma still uses Nitrogen only for many of their products.
http://www.gammasports.com/gamma.cfm?product=922
The Meat
Hall of Fame
PV=nRT
The ideal gas law. Temperature always affects pressure and volume negatively or positively, got to hate the laws of nature.
rafazx10
Rookie
PV=nRT
The ideal gas law. Temperature always affects pressure and volume negatively or positively, got to hate the laws of nature.
Yes but some gases expand (increase the ball pressure) more than the other with the same temperature change.
Would be nice to have a more consistent pressure, ball gain a lot of heat when you are hitting, while the others cool down on the court.
The Meat
Hall of Fame
I need to one day create pressureless balls that feel and imitate a natural pressured ball's bounce, would make a lot of money off of that.
SystemicAnomaly
Bionic Poster
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SystemicAnomaly
Bionic Poster
P=nRT/V
What, in this equation, would account for that? Since the Volume of the ball does not change appreciably, everything on the right side of the equation above is essentially a constant except for Temp.
Is it possible that some gasses act more like an ideal gas than others?
ricki
Hall of Fame
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
The Meat
Hall of Fame
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.
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.
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coachrick
Hall of Fame
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
Bionic Poster
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.
Ronaldo
Bionic Poster
So that is why some balls rattle when shaken
The Meat
Hall of Fame
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
Bionic Poster
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.
Nostradamus
Bionic Poster
i thin you are right. it is liquid nitrogen
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.
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.
Ronaldo
Bionic Poster
Ty, never could recharge dead balls even after two weeks in my tank at 25-30 psi. Awesome sound though, unleashing the pressure.
