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Author Topic: Why does the body not get crushed under atmospheric pressure?  (Read 3627 times)

Offline raghusesha

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The living cells in the body counter the pressure of atmosphere.  Why then, does the body not get crushed after a person is dead?


 

Offline MartinTheK

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Why does the body not get crushed under atmospheric pressure?
« Reply #1 on: 22/08/2010 17:42:57 »
Your initial premise is not correct. The cell does not resist implosion because that is a feature of life. A water balloon does not implode and it is no more alive than a stone.

The atmospheric pressure balances the internal pressure of the cell - or at least the vapor pressure of the water which is the major constituent of the cell's cytoplasm. If you subject a cell to extreme vacuum the water will boil and rupture the cell. Water is much more difficult to compress. I think you could possibly compress it to the solid state - I don't recall the phase diagram off hand - but that pressure would not be too far off that required to transform the cell's carbon into graphite or diamond.

However some sorts of political pressure can make politicians very small indeed.
 

Offline tommya300

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Why does the body not get crushed under atmospheric pressure?
« Reply #2 on: 22/08/2010 20:56:20 »
Your initial premise is not correct. The cell does not resist implosion because that is a feature of life. A water balloon does not implode and it is no more alive than a stone.

The atmospheric pressure balances the internal pressure of the cell - or at least the vapor pressure of the water which is the major constituent of the cell's cytoplasm. If you subject a cell to extreme vacuum the water will boil and rupture the cell. Water is much more difficult to compress. I think you could possibly compress it to the solid state - I don't recall the phase diagram off hand - but that pressure would not be too far off that required to transform the cell's carbon into graphite or diamond.

However some sorts of political pressure can make politicians very small indeed.
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ALLotropes of Carbon?
'


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[size=09pt]Eight allotropes of carbon:
 a) Diamond, b) Graphite, c) Lonsdaleite,
 d) C60 (Buckminsterfullerene or buckyball),
 e) C540, f) C70, g) Amorphous carbon,
 and h) single-walled carbon nanotube or buckytube.[/size]

http://en.wikipedia.org/wiki/Allotropes_of_carbon

http://www.dendritics.com/scales/c-allotropes.asp

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« Last Edit: 22/08/2010 21:03:29 by tommya300 »
 

Offline MartinTheK

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Why does the body not get crushed under atmospheric pressure?
« Reply #3 on: 23/08/2010 07:34:56 »
Actually allotropes are a pure single element...you would have to get the carbon out of the cell in pure form.

Water itself has 15 phases most of which are different forms of solid ice.

Here is what I found in the wikipedia article on ice under the subsection on phases...

"Ice formed at high pressure has a different crystal structure and density from ordinary ice. Ice, water, and water vapour can coexist at the triple point, which is exactly 273.16 K (by definition) at a pressure of 611.73 Pa.

Subjected to higher pressures and varying temperatures, ice can form in fifteen separate known phases. With care all these types can be recovered at ambient pressure. The types are differentiated by their crystalline structure, ordering and density. There are also two metastable phases of ice under pressure, both fully hydrogen-disordered; these are IV and XII. Ice XII was discovered in 1996. In 2006, XIII and XIV were discovered.[36] Ices XI, XIII, and XIV are hydrogen-ordered forms of ices Ih, V, and XII respectively. In 2009, ice XV was found at extremely high pressures and −143 C.[37]

As well as crystalline forms, solid water can exist in amorphous states as amorphous solid water (ASW), low-density amorphous ice (LDA), high-density amorphous ice (HDA), very high-density amorphous ice (VHDA) and hyperquenched glassy water (HGW).

In outer space, hexagonal crystalline ice (the predominant form found on Earth) is extremely rare. Amorphous ice is more common; however, hexagonal crystalline ice can be formed via volcanic action.[38]"

I wonder if some of these more exotic ice crystals may exist deep within glaciers or at extreme depths  were very exotic forms of "life" may exist?
 

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Why does the body not get crushed under atmospheric pressure?
« Reply #3 on: 23/08/2010 07:34:56 »

 

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