# Re: Altitude pressures in bagged fish

```If a train leaves Denver going 600 miles per hour ... and a second train
leaves Chicago traveling at 300 miles an  hour - how long will it take
Santa Claus to ....

Errrr never mind - just had a really bad flashback to high school math
class ...

<smiles>

Tom

At 08:10 AM 8/24/01 -0700, you wrote:

>>From: Christopher.W.Vasold at jci_com
>>To: KillieTalk at aka_org
>>Subject: Altitude pressures in bagged fish
>>Date: Fri, 24 Aug 2001 07:20:30 -0700
>>
>>
>>All,
>>
>>Okay here is one for you scientists. A couple of us have been debating
>>the possible effects/potential problems of transporting bagged fish from
>>my sisters place in town, about 6500 ft to her summer home in the mountains
>>which is close to 14,000 ft.
>>The air in the bag of fish has a volume of 500ml in town where
>>the atmospheric pressure is 600 mm of Hg.When she takes this bag to
>>the top of the mountain where the pressure is 420 mm of Hg, assuming
>>  the temperature will be kept the same, what will happen to the
>>volume of air in the bag? I suspect it will increase ( inversely?).The big
>>question is will the increase be linear at the same % increase as the
>>Atmospheric
>>pressure decrease? The two numbers we have been kicking around are 650ml
>>and 714 ml.
>
>
>It depends on how much stretch is in the bags, so is pretty hard to
>calculate. P1V1=P2V2 though. The pressure inside the bag will appear to
>rise as the altitude increases (outer pressure drops), but bag tension
>will limit volume change.
>
>I cross the Sierras at about 9000ft from sea level or below, several times
>a year. The change in tighness of a fish (or potato-chip) bag is quite
>impressive.
>
>Since aircraft cargo is allowed to go up to 4000-5000 ft. equiv. pressure,
>I make sure that shipping bags have *lots* of air (compressible), very
>little water (incompressible), and are just as soft as possible and still
>eliminate corner traps in double bags.
>
>Wright
>
>
>_________________________________________________________________