A theory for your comments.

Discussion in 'Science' started by LeftRightLeft, Oct 17, 2018.

  1. LeftRightLeft

    LeftRightLeft Well-Known Member

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    Tonight as we went to bed my partner asked if I wanted the fan turned off.

    I replied if it wasn't bothering her I preferred it on. It was easier for me to breath. I have COPD and yes it is my own stupid fault.

    I had never thought about it analytically before but being among other things a biochemist I have this theory.

    When we breath we breath in oxygen and breath out CO2. If motionless in a room where the air is still causes a concentration gradient of increasing CO2 and decreasing oxygen around the sleeper.

    This is solved by moving the air or tossing and turning.
     
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  2. perdidochas

    perdidochas Well-Known Member

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    I toss and turn with fans and a CPAP machine on.
     
  3. tecoyah

    tecoyah Well-Known Member

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    There is a reason that placing a plastic bog over your head is a bad idea....but breathing normally does not increase local CO2 concentration markedly.
     
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  4. yiostheoy

    yiostheoy Well-Known Member

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    Possible. Especially since CO2 is a heavier gas.
     
  5. LeftRightLeft

    LeftRightLeft Well-Known Member

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    Yeah a bit more sensible response than "that's why we don't put plastic bags over our heads". He must be a conservative.

    Yes and in a still room it only has diffusion apart from the turbulence of breathing.

    I'm not talking about a dramatic difference like you would have to sit up so you didn't suffocate but enough lowered oxygen concentration for our subconscious to seek cleaner air. There maybe other factors that need to be in play, like I always close the bedroom door .
     
  6. yiostheoy

    yiostheoy Well-Known Member

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    When my cat takes a dump in his litter box in the bathroom I then have to run and close the bathroom door after him too.

    And turn on the fan.

    But (no pun intended) that is due to methane being a lighter gas not heavy like CO2.
     
    Last edited: Oct 19, 2018
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  7. LeftRightLeft

    LeftRightLeft Well-Known Member

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  8. LeftRightLeft

    LeftRightLeft Well-Known Member

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    Not laughing at the science just imagining the scene
     
  9. DennisTate

    DennisTate Well-Known Member Past Donor

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    Your idea seems related to another discussion that I have going on here.......

    My question to you is......
    should the people who are all worried about the fact that the resulting fuel from this technology will be burned.....
    Should this be their primary concern....... as their replies to the video seem to imply..... or should they lighten up and be extremely glad that this intriguing and promising advancement has been made?

    http://www.politicalforum.com/index.php?threads/is-this-the-answer-to-atmospheric-carbon.543753/

    Is this the answer to atmospheric carbon?


     
    Last edited: Oct 31, 2018
  10. LeftRightLeft

    LeftRightLeft Well-Known Member

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    My god you will invade any thread. Good bye
     
  11. iamanonman

    iamanonman Well-Known Member

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    CO2 may be heavier than the surrounding air, but it still won't fall to the floor or pool near your nose. It is subject to dispersion via Brownian motion. This is because all of those O2, N2, and CO2 molecules are zipping this way and that and are in a constant state of random motion with one another. They mix naturally both horizontally and vertically as a result. At typical pressures the mean free path of a molecule is on the order 100 nm. That's how far on average it will travel before it collides with another gas molecule and thus bouncing off with each molecule conserving the original shared momentum. The speeds of these molecules are very fast. For nitrogen at room temperature we can see by using the equipartition theorem that the molecules will zip around at 500 m/s (over 1000 mph). The collisions are happening so frequently that even in a room with no ventilation the molecules will all eventually mix out evenly...mostly anyway. Gravity does have an impact, but the effect is only perceptible over huge distances (several kilometers). So yes, CO2 will stratify vertically given a large enough (height-wise) vessel to allow for that effect to take hold. It just takes a really deep vessel (several kilometers high) for this effect to be perceptible. And even then it's not a clean stratification. That's part of the explanation why ambient CO2 (or O2 or N2 or whatever) concentrations are mostly homogenous over the depth of the troposphere. But, the troposphere is also highly agitated so even as the gases are starting to stratify winds just mix it all up again. But back to the original question. No, CO2 will disperse evenly in the confines of a typical room even in the absence of ventilation or air movement. The one notable exception is if you impede the dispersion process by covering your face with a blanket or something like that.
     
    Last edited: Nov 1, 2018
  12. Pycckia

    Pycckia Well-Known Member

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    CO2 being heavier than O2 it should pool on the floor. Turning on the fan might make things worse, not better.
     
  13. iamanonman

    iamanonman Well-Known Member

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    Nah...CO2 does not pool at the floor. It's the same reason that oxygen doesn't pool on the floor either. It's a good thing that gases don't stratify in typical living environments. If they did then in a typical room with an 8 foot high ceiling argon would rest on the floor about 1" deep, oxygen would be next and would go no higher than 21", and nitrogen would fill the remaining space from 21" to 96". You'd die from nitrogen narcossis unless you constantly crawled on your hands and knees bobbing you head in and out of the oxygen and nitrogen layers to ensure you got the typical 20% O2 mix you're body is used to.
     
  14. iamanonman

    iamanonman Well-Known Member

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    The reason why cat turds stink when you put your nose up to them is because they are the source of the pungent gas. The gas still disperses and mixes out over time, but the densities are persistently higher the closer you are to the turd. That's because the chemical reactions that are releasing the gas are still taking place. Remember, a cat turd isn't same package that holds a fixed amount of gas and once released it's all gone. If that were the case then your cat would have farted it all out leaving you with a nice aroma free turd. Also, the fact that you are able to smell something so vile anyway is because you are getting turd molecules (gaseous as well as solid particles that are aerosoled) in your nose and likely your mouth as well. I hope you guys are all enjoying your lunch this afternoon.
     
    Last edited: Nov 1, 2018

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