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Subject:
nuclear energy of the human body
Category: Science > Physics Asked by: dudester123-ga List Price: $10.00 |
Posted:
08 Jun 2006 23:56 PDT
Expires: 08 Jul 2006 23:56 PDT Question ID: 736619 |
I understand that a single nuclear fission reaction of one uranium atom is enough to make a grain of sand jump. So, how much nuclear energy is in the human body? How can I quantify it? I understand that fission can only take place with uranium or plutonium. But is it possible to quantify the amount of nuclear energy in a human body? |
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Subject:
Re: nuclear energy of the human body
Answered By: hedgie-ga on 10 Jun 2006 00:19 PDT Rated: |
Elements with mass number larger then Iron may produce energy by fission --------- comment on comments--\\ This was correctly noted yonr. But then he switched to C-14, which radioactive, not fissionable. Confusion was futher compouded by qed, which is not unususal, who said " all atoms conrain nucleons" That is true, but that does not make them 'nuclear materials' . Nuclear Materials are those used in the nuclear industry, not those having some nucleons in thehm http://nuclearweaponarchive.org/Nwfaq/Nfaq6.html http://www.nrc.gov/materials.html Special Nuclear Material - consists of uranium-233 or uranium-235, enriched uranium, or plutonium ----------------------------// Let's continue the answer with respect to energy which can be released by fission. Elements with mass number larger then Iron may produce energy by fission http://hyperphysics.phy-astr.gsu.edu/hbase/nucene/nucbin.html Those elements are shown here (click on atomic mass, , Iron Fe is abour 55 ) http://www.chemicalelements.com/ binding energy curve is shown here: http://www.einstein-online.info/en/spotlights/binding_energy/index.html Sample calculation: energy released in nuclear fission It has Sample calculation: energy released in nuclear fission at the bottom of the page You can expect some 10 MeV in sub-uranium fission, so multiply that bu number of atoms in human body which has mass number above 55. Elements in human body are listed here: http://www.lenntech.com/Periodic-chart-elements/human-body.htm Heavy elelents are present only as traces (heavy metals are toxic) mass number traces Copper 63 traces Zinc 65 traces Selenium 78 traces Molybdenum 95 ... You can ask for additional details here: http://library.thinkquest.org/17940/texts/binding_energy/binding_energy.html | |
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dudester123-ga
rated this answer:
Please, don't worry about insulting me by talking down to me.... |
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Subject:
Re: nuclear energy of the human body
From: yonr-ga on 09 Jun 2006 09:12 PDT |
The only nuclear matter that I'm aware is present in the human body in any noteworthy quantity is C-14. One atom of C-14 produces 0.156 mega-electron volts (http://www.ehs.unr.edu/Default.aspx?tabid=68#c14). This is equivalent to 1.60 * 10^-13 J, or 2.27*10^-11 lb*in. So one C-14 atom can lift 2.27*10^-11 lbs 1 in, or 1 lb 2.27*10^-11 ins, and the proportional amonts. Now the question is how much C-14 is there in the human body... There are 95 micrograms (10^-6 g) of C14 in the body. http://www.vanderbilt.edu/radsafe/9712/msg00510.html Because C14's atomic mass is 14, multiply 95/1,000,000 by 14 to get the number of moles of atoms. We have (95/1,000,000)(14) = 1.33*10^-3. Since there are 6.0225 × 10^23 atoms in every mole, multiply this by 6.0225 × 10^23. (1.33*10^-3)*(6.0225 × 10^23) = 8.01*10^20. But this only gives the number of atoms. Now we need to multiply by the work done by each atom: (8.01*10^20 atoms)*(1.60 * 10^-13 J/atom) = 1.28*10^8 J. So you can move 1.28*10^8 Newtons one meter. At Earth's surface, that would be just about 1.28*10^7 kg, or 1.28*10^4 metric tons. So you can lift about 1,280 tons one meter into the air with the nuclear energy in your body. That's about 250 elephants! Or you could toss one elephant 250 meters (762 feet). Or anything proportional. |
Subject:
Re: nuclear energy of the human body
From: qed100-ga on 09 Jun 2006 09:29 PDT |
yonr, What do you mean, the only "nuclear" matter in the human body is C-14. Every single atom has nuclear matter within it: the nucleons themselves. It's not an issue of the radioactivity of an element. In anything more massive than straight hydrogen, there is energy associated with holding the nucleons together. That energy is the nuclear energy of the atom. As for dudester123's question, it is possible to quantify the nuclear energy in the human body. To arrive at a very precise number would, however, require a thorough breakdown of all the chemical elements' abundances in the body (how many atoms of each element are present), and then multiplying those numbers by the binding energies of the various elements' nuclei (including by isotope). |
Subject:
Re: nuclear energy of the human body
From: yonr-ga on 09 Jun 2006 12:22 PDT |
qed100, it appears that I misinterpreted the question. Still, I think it's kind of amusing that the decay of the C14 in our bodies can lift elephants. As for the nuclear matter in the human body... for all the elements up to Iron and nickle it takes more energy to separate the nucleus than you get from dividing it. Fission doesn't really pay off energywise for most stable atoms. That's why fusion produces energy for the combination of atoms up to Fe and Ni, and actually consumes energy thereafter. The reverse can be said for fission. If you care about the fusion of the elements that make up 96% of the body, we're dealing with 10% of the body's mass in hydrogen, 63% in oxygen and 23% in carbon. The other 4% is negligable. For a 60 kg person (about 132 lbs) that would be 6 kg hydrgen, 38 kg oxygen and 14 kg carbon. Carbon and oxygen don't really synthesize well, but if you want to know how much energy can hypothetically be drawn from them in a perfect system, I'll get there in a second. Supposing we could conduct all the hydrogen perfectly (the deuterium-tritium process), 5 atoms should produce 17 MeV. Again we do the stoichiometry: (15 kg)*(1000 g/kg)*(1 mol/1 g)*(6.0225*10^23 atoms/mol) = 9.03*10^27 atoms. (9.03*10^27 atoms)*(17 MeV/5 atoms) = 3.07*10^28 MeV (3.07*10^28 MeV)*(1.6 x 10^-13 J/MeV) = 4.91*10^15 J This on earth's surface would lift about 4.91*10^14 kg-meters. That'll launch an elephant 100,000,000 kilometers (although Earth's gravity wouldn't really hold him at that point). This would be an opportune time to correct my calculation on C14: I forgot to multiply by 1.6*10^-13 J/MeV. Alas, our radioactive carbon would only launch an elephant 32 meters. If you find similar errors here (although I'm checking more scropulously, because the first was done right as I was exiting the house for an appointment), let me know. I'm curious to know the answer to this question as well. The most energy-efficient fusion of oxygen produces 16.5 MeV for every two atoms of oxygen used. (http://www.astrophysicsspectator.com/topics/stars/FusionCarbonOxygen.html) Stoichioetry: (38 kg)*(1000 g/kg)*(1 mol/16 g)*(6.0225*10^23 atoms/mol) = 1.43*10^27 atoms (1.43*10^27 atoms)*(16.5 Mev/2 atoms) = 1.18*10^28 MeV (1.18*10^28 MeV)*(1.6 x 10^-13 J/MeV) = 1.89*10^15 J On earth, that would do about 1.89*10^14 kg-meters of work, lifting about 40% of an elephant 100,000,000 kilometers. Assuming the most energy-efficient path (to Mg24), carbon would release 14 MeV of energy for every two atoms (http://www.astrophysicsspectator.com/topics/stars/FusionCarbonOxygen.html). Stoichiometry again: (14 kg)*(1000 g/kg)*(1 mol/12 g)*(6.0225*10^23 atoms/mol) = 7.03*10^26 atoms. (7.03*10^26 atoms)*(14 MeV/2 atoms) = 4.92*10^27 MeV (4.92*10^27 MeV)*(1.6 x 10^-13 J/MeV) = 7.87*10^14 J At sea level, this would carry 7.87*10^13 kg-meters. This would lift an elephant and a half about 10,000,000 kilometers. So, for our grand totaly, we have 7.59*10^15 J, or about 7.59*10^14 kg-meters, or 7.59*10^8 ton-km at sea level. So we can throw an elephant about 150,000,000 km (a little under 100,000,000 miles). Let's see how much that is relative to our distance to the sun: We are 8.3 light minutes away from the sun. Light travels 300,000 km/sec. (300,000 km/sec)*(60 sec/1 min)*(8.3 min) = 1.49*10^8 km So we're 1.49*10^8 km away from the sun. That's practically identical to our elephant-launch distance. SO IN CONCLUSION: Assuming earth's gravitation pull remains constant from here to the sun (which it doesn't, but work with me here), the body of a 132 lb person will produce enough energy in nuclear fusion of hydrogen, oxygen and carbon (assuming perfectly ideal conditions and reactions) to propel an elephant from earth to the sun. |
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