You Rang...
Good discussion guys, thanks for inviting me
Cyberia!
Jim O basically nailed it but I'll add a few clarifying details.
First invoke the "Ideal Gas Law":
PV=nkT
P=Pressure
V=Volume
T=Temperature
n=number of atoms in the volume
k=Boltzman's constant
(This is where
Jim O's equation was derived from.)
Since
n and
k are constants, forget about them since they don't change. The rest of the variables are linearly proportional.
Therefore, if you had a balloon full of gas, took off in a bomber and flew to an altitude where the P = 1/3 then the Volume would change by a factor of 3, or 300% (3/1). However, that is for CONSTANT "T" (hence the misunderstanding)!
In fact, the temperature drops about 6.5 degrees Kelvin (and Celcius) per 1,000 feet so at 20,000 feet the temperature has gone DOWN 130 degrees. Water freezes at 273 Kelvin so if it was a cold day (32 degrees F = 0 C = 273 K), the temperature drops by about a factor of 2 so the gas only expands 150%, not 300 percent. The higher you go the colder it gets so while P decreases, so does T and therefor the V doesn't increase as much as one might think.
OK, so much for a balloon. Now think of the gas in your stomach (most of what is in your stomach/intestines is liquid). It is inside a pressure vessel at a constant 98.6 degrees F so it behaves a bit differently then a balloon. If the pressure inside your gastrointestinal tract exceeds the outside pressure, the overpressure will be relieved in the normal fashion, a "fart" or a "burp" or both. In an extreme case (drank a bottle of soda/beer before take off) one might vomit to relieve the pressure which would be construed as "altitude sickness". So, even though the volume might increase, the pressure is maintained by "venting".
For one to die of overpressuring the stomach, you would have to "plug all the vent holes" first which is highly unlikely. At VERY high altitudes (100,000 feet?) one will eventually get the "bends" because the blood will boil in a low pressure atmosphere. However, a WWII bomber would never get close to that altitude.
By far the greatest danger of flying 10,000+ feet is "Hypoxia" which is a fancy name for "lack of oxygen". Above 10,000+ feet the amount of Oxygen you can get into your lungs/bloodstream is not enough to sustain consciousness and eventually you pass out and die. The higher you get, the worse the problem. At 30,000 feet you would probably only last a couple minutes due to lack of Oxygen. It's just like being strangled to death except you don't feel the tight grip around your windpipe as you life is slowly sucked away...
I hope this helps.
Anytime you guys have a physics/science type question, don't hesitate to PM me!
As Cyberia correctly pointed out:
Quote:
Originally Posted by cyberia
I'll PM him a link. He eats this stuff up.  |
