First excuse my sometimes bad english… I’ll do my best
I’m currently working on a sci-fi/thriller story where the so-called ‘memory of water’ would be the central point. One character (a killer) would have the ability to ‘evaporate’ all his bodily water, leaving only the remaining chemicals as a “small mound of sand/dust”, and then be able to “recreate” is body from the said chemicals in another place, allowing him to create a series of “closed room” murders.
It’s often said that a human body contains 80% of water, but through catalysis many of the chemicals present in a human body would ‘create’ more water (for example the catalysis of all molecules with a -COOH radical would ‘create’ more H2O -and CO2)… I unfortunately don’t have enough scientific background to be able to come up with the numbers.
Here’s my question: Can anyone give me a more accurate percentage of the bodily mass that is constituted of water in one form or another?
As an aside, to help me further the plot of my story, I would like to know if the human body contains chemicals that could be considered “rare” enough so that the killer’s source for the chemical could be tracked down by the police… Can you help me?
I believe the metabolisation of starch results in water and CO2. A bit off-topic, but wouldn’t evaporation of water leave behind every bone? Hardly a neat mound of dust. Also, when reconstituting, those bones must be arranged precisely, or the character would end up rather deformed. (or worse)
You will doubtless get many people telling you reasons why this premise is scientifically extremely implausible. Nonetheless, to answer your question: According to this page (first Google hit for “elemental composition human body”), a 70 kg human contains about 43 kg of oxygen and 7 kg of hydrogen. Since water is eight ninths oxygen by weight, this means that oxygen will be our limiting reagent (that is to say, we will use up the available oxygen first, with some hydrogen left over). 43 kg of oxygen will combine with 5.375 kg of hydrogen to form 48.375 kg of water. This will leave 21.625 kg of remains, of which 16 kg will be carbon, 1.8 kg will be nitrogen, 1.625 kg will be leftover hydrogen, 1 kg will be calcium, 0.78 kg phosphorus, and the remaining kilogram or so will be a mixture of small amounts of potassium, sulfur, sodium, chlorine, and other elements.
Well, our bones contain quite alarge amount of water, it’s what keeps them ‘elastic’. The absence of this water causes osteoporosis and ‘glass bones disease’… So I guess the total dispartion of the water from the bones would make them so fragile they would “crumble to dust” under their own weight.
That’s where the “sci-fi part” of the story is… The ‘memory of water’ allows for the (near*) perfect reconstitution of the body… (* I won’t give the whole plot but the reconstruction is actually far from perfect )
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Now that’s weird… Looking at a medical book I saw that 80% of a human body is water, hence 56kg out of 70kg, this doesn’t fit at all with the site’s figures! Since there should be even more Hydrogen and Oxygen than that in a body, included in other chemicals, it seems one of these sources is wrong…
Actually all the N2, CH4, and other chemicals that are gazeous at room temperature would not be found in the remains…
Please forgive me for this unscientific answer, and I apologize if its a bit morbid.
When my grandparents were cremated, the resultant ash and cremains was about… a good 5 pound sack full. Both weighed about 150 pounds on cremation, and each bag was roughly the same.
I assume cremation, via burning, removes all the liquids present, leaving only the solids behind.
That’s right but though cremation a lot of the body’s Carbon gets ‘wasted’ (transformed to CO2) which would not be the case in the situation of my story…
The problem here is that the question is a bit ill defined. Hence the answers vary a bit. The human body contains a certain amount of water molecules in the form of H2O. Counting these only would give a low figure. If you count every oxygen and every hydrogen atom possible, that would give a rather high figure. If you counted H2O molecules and molecules that could easily be made into H2O you could get an intermediate figure. As one student of mine says, “It’s like comparing Fresca and Hitler: One’s a refreshing soft drink, and one’s a fascist dictator.” Of course, both are mainly water (or “was” in the case of Hitler), but in the case of Fresca, the water is very disorganized. IMHO, the amount of water in a human means that, the amount of actual H2O molecules, hence a lower figure. Including easily made water molecules will not change the number too much, I do not believe.
Well, I’m only in a early stage in my story writting… Some ideas need a lot of reasearch. I guess that the killer would not be able to extract all the Hydrogen and Oxygen atoms from his body but only those in H2O form and those that could be easily extracted through catalysis (all the -OH radicals for example)… I think that about 20Kg of "remains would be a good figure (but all the gazeous results of the catalysis would have to be substracted from this figure).
Some of the discussion here got me thinking that it could be “interesting” to have the killer leave his skeleton covered with ‘dust’ -alctually all the composants of his body behind. The skeleton might be so ‘dried out’ that it would crumble to pieces when touched.
Well, I’ll get in touch with a forensics specialist to get a better picture. Thanx to everybody for the help…
If you’re interesting I’ll let you know when (if?) that story of mine will get published. Even if the plot is kindda ruined for you all now
