Storing tennis balls in freezer

diggler

Professional
In theory this should slow the loss of pressure. Has anybody actually done this? How much difference does it make?
 

donnygg

Rookie
Don't think it'll make much difference, unless you have cryogenic freezers. Room temperature is about 300K, fridge about 277K and freezer about 253K. So considering absolute temperature, I don't expect the temperature in household freezer to slow down pressure loss much.

However, if the balls are flat (i.e atmospheric pressure), by storing them at 150K (-123C), the pressure in the ball will half. After the internal pressure has equilibrated to atmospheric pressure at the cryogenic temperature, theoretically, the ball will be revived at room temperature as the pressure doubles! (provided the balls are treated with care at cryogenic temperature, since they are a brittle as glass then)
 

diggler

Professional
I put some balls in the freezer at my tennis club but this is a very unscientific approach as I don't have a control sample. Ideally I should have but some new balls in the freezer and some new ones in the cupboard and tested them later.

In the freezer, the pressure inside the balls should fall. However, the pressure in the freezer is also lower than outside. The two effects may cancel each other out.

After taking the balls out of the freezer, I assume they need a few minutes to warm up.


Note that in 2014 the balls at Wimbledon

  • Must be kept at 68° Fahrenheit (in a fridge) courtside to keep them in perfect condition.

http://scn.sap.com/community/business-trends/blog/2014/06/18/new-balls-please-it-s-time-for-wimbledon

I think the players complained and they are now kept in the can until required.
 

Nostradamus

Bionic Poster
In theory this should slow the loss of pressure. Has anybody actually done this? How much difference does it make?
this would kill the ball and make it lose all pressure. I would normally store the balls in the furnace. that works much better. and hotter air would keep the pressure high much longer.
 

Muppet

Legend
PV = nRT

pressure
volume
n and R are constants
temperature

Assuming that the balls will hold the same volume, we see that pressure and temperature are on opposing sides of the equation. As one goes down, the other must go down. A decrease in T will cause a decrease in P, until the balls are returned to the original T. In a perfect system, the balls will return to the original P. But in actuality, the balls will be worse for wear and will lose some pressure.
 

esgee48

Legend
Diggler: If the outside the freezer air pressure was lower than inside the freezer, you would have large volume air moving into the freezer every time you open the door. The external and internal air pressure should be the same. Fans inside a walk-in freezer are there to circulate the chilled air so that the entire volume is uniformly cooled. That cold air will spill out of a freezer because cold air is denser than warm air.
 

mxvb

Rookie
You kill the rubber inside the tennisballs so you would make them unplayable!
As @Nostradamus said, balls for tournaments are stored in a heated container (I saw this at the Koksijde Ladies Open (Belgium), €25.000 a few years ago).
 

Nostradamus

Bionic Poster
You kill the rubber inside the tennisballs so you would make them unplayable!
As @Nostradamus said, balls for tournaments are stored in a heated container (I saw this at the Koksijde Ladies Open (Belgium), €25.000 a few years ago).
Agree, like I said,,, Furnace or Oven is the BEST.
 

diggler

Professional
Interesting thoughts. Thanks. The pressure in the ball will decrease due to the lower temperature. If the ball shrinks, the pressure drop will be lower. The freezer has a low temperature, however, it does not seem to have a low air pressure. There seems to be some pressure equalisation mechanism.

The difference in air pressure between the ball and freezer would be lower than between ball and outside air. I would expect the balls in the freezer to maintain pressure longer.

On a side note, if the balls at Wimbledon are kept in a fridge at 68 degrees F, but the temperature that day is hotter, then the balls would increase in bounce as they warm up.
 

diggler

Professional
I put some balls in the freezer a few days ago. I took them out of the freezer yesterday. Straight out of the freezer, they bounce like rocks. After 10 minutes they have warmed up and bounce like normal. The rubber seems to be undamaged and the felt doesn't have any extra moisture. Freezing doesn't seem to make balls any worse.
 
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