What is the boiling point of blood at low air pressure?

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Discussion Overview

The discussion revolves around the boiling point of blood at low air pressure, exploring the implications of atmospheric pressure changes on physiological conditions. Participants examine the relationship between pressure and boiling point, as well as the effects of sudden pressure loss on the human body.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant claims that atmospheric pressure of about 100,000 pascals can accelerate a 100 kg body significantly if the pressure on one side is suddenly removed, questioning the validity of this claim.
  • Another participant explains that an object with a one-meter-squared area experiences a force due to atmospheric pressure, but emphasizes that achieving constant pressure while accelerating is practically impossible.
  • Anecdotal evidence is presented regarding the energy stored in air pressure, with a reference to the destructive potential of an exploding scuba tank.
  • Concerns are raised about the physiological effects of losing atmospheric pressure, including boiling blood and collapsing lungs.
  • It is stated that the boiling point of blood, primarily composed of water, is dependent on pressure, with a specific mention of the saturation temperature of water at low pressures.

Areas of Agreement / Disagreement

Participants express varying views on the implications of pressure loss on the human body and the physics of acceleration due to atmospheric pressure. There is no consensus on the initial claims regarding acceleration or the anecdotal evidence provided.

Contextual Notes

The discussion includes assumptions about pressure dynamics and physiological responses that are not fully explored or resolved, particularly regarding the exact conditions under which blood would boil.

BigMacnFries
I have read that air pressure is about 100,000 pascalls
which = 100,000 Newtons/m2
which is enough to accelarate a 1kg body with a surface area of 1m2 to 100,000 m/s in one second
which is enough to accelarate a 100kg body with a surface area of 1m2 to 1000m/s in one second.
Is this right. Since i am about 100kg and have a front body surface of about 1m2 is it true that if the air pressure on my back suddenly dissaperaed I would be 1km that way in a little over a second?
 
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An object with a one-meter-squared side experiences a little over a hundred thousand Newtons of force, over that area, due to atmospheric air pressure.

If there were absolutely no opposing forces, such an object with a mass of only 1 kg would experience an acceleration of a little over 100,000 m/s^2.

Of course, it would be quite a feat to arrange a system in which the pressure did not change at all as the object were accelerated. Consider a potato gun or pneumatic rifle. As the projectile begins moving, the cavity behind it gets larger, and the pressure in that cavity is reduced. When fired with atmospheric pressure into a vacuum, the projectile would experience that 100,000 m/s^2 acceleration only instantaneously at the beginning of its movement; at all later times the acceleration would be much less.

Anecdotally, air pressure can store very large amounts of energy. A scuba tank exploding inside a dive shop, for example, can pretty much destroy the whole shop.

- Warren
 
chroot said:
Anecdotally, air pressure can store very large amounts of energy. A scuba tank exploding inside a dive shop, for example, can pretty much destroy the whole shop. [emphasis added]
"Anecdotally"? Did you really think we could let that go without expansion (pun weak, but intended)?
 
You would not want to be in your body if the Earth suddenly lost its measly 15 psi atmosphere. Your blood would boil, lungs collapse... and it gets ugly after that.
 
Why would my blood boil etc?
 
Boiling point is dependent on pressure.

Blood is mostly water.

The saturation temperature of water at 0.04 bars (1 atm = 1.01325 bar = 14.696 psia) is 29.0°C (84.1°F). So if the temperature of blood is about 98.6°F (37°C), the blood would boil at 0.04 bar, which is still greater than vacuum (<<0.01 bar).
 

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