# You are breathing Caesar's death breath

Discussion in 'Free Thoughts' started by Ivan Seeking, Nov 17, 2003.

1. ### Ivan SeekingRegistered Senior Member

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According to classical thermodynamics, with every breath that you take, there is approximately a 100% chance that you will inhale at least one air molecule that was exhaled by Julius Caesar in his dying breath.

I just thought you might like to know.

3. ### curioucityUnbelievable and oddRegistered Senior Member

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And Julius Caesar also breathed the air molecule Totankhamun exhaled., right?
nice though

5. ### HaloFull Time Nerd-BomberRegistered Senior Member

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People inhale way too many dookie molecules too.

7. ### whitewolfasleep under the juniper bushRegistered Senior Member

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And with each breath that we take we may also inhale air particles that someone let out thousands of years ago, from a body hole below the belt.

On the serious note, where did you get that piece of information? Please provide a link and further ideas of the sort.

8. ### Ivan SeekingRegistered Senior Member

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No link, this is a simple calculation. I ran across this classical factoid in college.

If we consider the volume of air inhaled with each breath, about one liter I think, call this liter A, and then the number of molecules in that liter (A), and then if we distribute those molecules evenly throughout earth's atmosphere, we find that we have at least one of the original molecules from liter A, per liter [liter B] of atmosphere.

One liter of air contains about 2.7 E22 molecules

The mixing atmosphere is about 50 KM high; which yields a total mixing volume of about 6 E8 cubic miles.

2.7E22 / 6 E8--> ~4.5 E13 molecules from liter A per cu mile of atmosphere.

This reduces to about 300 molecules per cu ft, and finally 10 molecules from liter A in liter B.

So by this rough estimate, and after sufficiently mixing the air for about 2000 years, we expect to find about 10 molecules from liter A in any liter B.

Edit: the first number was given as 2.7 E23 instead of E22, however the next calculation accounts for this.

Last edited: Nov 19, 2003
9. ### curioucityUnbelievable and oddRegistered Senior Member

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Wow. Patience or boredom?

Last edited: Nov 19, 2003
10. ### Ivan SeekingRegistered Senior Member

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883
Eh, that's just a cup-of-coffee-and-the-back-of-a-napkin problem. You should see what I can do with a pot of coffee and a few paper towels.

11. ### curioucityUnbelievable and oddRegistered Senior Member

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hehhehe
by the way, as time goes by, would the number of molecules remaining increase or decrease?

12. ### Ivan SeekingRegistered Senior Member

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I don't understand what you mean. Could you try that again?

13. ### curioucityUnbelievable and oddRegistered Senior Member

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Okay

<i>quoted from Ivan Seeking</i>
<b>So by this rough estimate, and after sufficiently mixing the air for about 2000 years, we expect to find about 10 molecules from liter A in any liter B.
</b>

That's what I questioned.

Would the 10 molecs figure decrease or increase if the 'mixing' period were, say, 10 millenia (10000 years)?

14. ### Ivan SeekingRegistered Senior Member

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That's just how long we must stir the pot before mixing is complete. After that, in principle it makes no difference; its mixed. In reality, eventually something will break down those molecules by reacting with them chemically. So eventually we start getting into trouble. I don't know how long this takes.

15. ### curioucityUnbelievable and oddRegistered Senior Member

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Broken down chemically..... Are you suggesting that the 10 molecs figure may fall into some new figure like 5 for a longer period?

16. ### Ivan SeekingRegistered Senior Member

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No, I mean that the O2 and CO2 molecules will react and be split up such that the Oxygen and Carbon atoms will still be around, but they are no longer associated as a complete molecule. They go their separate ways to to speak.

If we look more closely this get much more complicated. Note that I kept using the word "classical". This means that we can ignore some of the tremendous complications brought into this problem by Quantum Mechanics. That would go way beyond the scope of my napkin.

17. ### whitewolfasleep under the juniper bushRegistered Senior Member

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Well since you're typing it, it's beyond your napkin already, so.... Develop your idea as far as you can.

18. ### FloresRegistered Senior Member

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Here is the error in your computations

How do you know that the air we breath distributes evenly throughout the earth? Don't you think that's an overly simplistic dumb assumption considering that density layers, temprature, wind, ect...all considered variable unknown parameters plays an important role in the air distribution across our atmosphere.

19. ### Ivan SeekingRegistered Senior Member

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Re: Here is the error in your computations

Sure. This chaos is what eventually assures even mixing.

20. ### Ivan SeekingRegistered Senior Member

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Well, this in an interesting fact from thermodynamics; not my idea by the way. I'm not inclined to write a paper on the subject.