Any physicists out there?
I was wondering how many atoms there are in a pair of trainers? I know that they weigh about 350g and I guess consist of about 50% nylon and
50% plastic.Does anybody know the maths for calculating a very approx. figure?
TIA Colin
... Perhaps I need a chemist rather than a physicist... whoops.
Colin
..or even a therapist perhaps? ;-)
Yes, you do. A-level chemistry.
There are approx 6 x 10^23 hydrogen molecules in 2g. A hydrogen molecule is
2 protons and 2 electrons. A neutron has almost exactly the same mass as a proton, and an electron is in comparison, mass-less. Most atoms contain about as many neutrons as protons (slightly more, on average). The mass of a proton and neutron is the same, no matter which molecules they are part of.That should get you started. Your biggest area of uncertainty is the composition of the material. It's going to be mostly organic, though.
He didn't even specify what shoe size, or whether he wanted airsoles.. LOL
eeks, it's an alarmingly long time since I've had to think of anything like this, but I think you may be over-complicating it a bit here, and for this estimate I don't think that you need to bring molecules into it - just the molecular weight of the constituent atoms themselves & some rough estimate of the elements & proportions of said elements in the material.
so, 1g of hydrogen has approx 6x10^23 atoms, as does 14g of carbon.
for a very,very rough order-of-magnitude estimation I might start off with the huge assumption that the trainers are constucted 100% of hydrocarbons which are mosly made up of long CH2 chains consisting of single carbon-carbon bonds and with negligible proportions of other stuff.
so in 14g + 1g + 1g = 16g of trainer you've got 1.8 x 10^24 atoms (3 atoms per "unit"). 350g of trainer is therefore a simple bit of arithmetic.
Of course you can now start refining that first stab a bit by looking into slightly more detail as to what actually makes up nylon & the other materials (there's Nitrogen & Oxygen in there IIRC), but to my mind the process is the same.
But, as I say it's been a long time & that could be complete b&&**x!
Dredging up some GCSE chemistry, 6*10^23 molecules of Carbon 12 weighs
12g. So if your shoes were made of Carbon, there would be 350/12 * 2 (atoms/molecule) * 6 * 10^23. So around 3.6 * 10^25 (can't be bothered pulling a calculator out).Of course, they're not made solely of Carbon atoms - quite a lot of Hydrogen as well, and other stuff, probably mostly lighter atoms. But I strongly suspect the exact answer doesn't matter - by the time you've got to the 10^25 bit, you know everything you need to.
Oh double that if you meant 350g/shoe, rather than /pair, which I'm guessing you did.
Why?
Ben
Plus chlorine, oxygen in the phthalates and Lord alone knows what in the pigments. At a very wild guess, about 70% of the model you suggest above would be where I'd go in the sweepstakes. Without detailed information about the polymers involved it is difficult to be accurate because terepthalates (Terylene (TM)) have a lower hydrogen loading and polypropylene higher than your quite reasonable model. Fluorinated or siliconised plastics throw more complications into what is already a morass.
Perhaps it would be simpler to assume the trainers are made of stainless steel as that is apparently a superior material for their construction. Ask Drool.
John Schmitt
Are you planning on constructing your own trainers from the raw ingredients? Blimey, that's a DIY task and a half... You're gonna need a really small pair of tweezers for a start.
Andy
That's going a bit too far. O-level will do.
Mr F.
No it won't, not these days - you need at least a degree.
Hi Colin
Would this be one of those conversations that started in the pub by any chance?
Dave
Well, O-levels don't exist any more. Knowledge of Avogadro's constant wasn't in my O-level course.
make it CxH2x and you won't be far wrong...
I'd agree with your outline method. The whole nub of the guesstimation comes down to "What is the average molar mass of 'trainer'?". I think the CH2 = (12+1+1)/3 = 4.7 (Carbon is mostly Carbon 12 not Radioactive Carbon 14) would make a lower bound. I expect that the percentage of heavier elements is relatively small to C and H although there may be a modest amount of O and N. I expect the soles are polyurethane. Urethane has molar mass of 89 with 13 atoms so that's an average gram molecular weight of 6.8. From what I can gather from wikipedia the average for Nylon 6,6 would be
5.9 g/mol.So taken together maybe an average of 6.4 g/mol.
Given 6E23 x 350 / 6.4 = quite a few.
Looks like we've been conned into doing someone's science homework.
True. Some interesting data at:
It was in mine (1980s), I think.
Not that I remember now what it was or why one would ever need it.
I hate chemistry.
Owain
It is something like 1 atom for every 0.0000000000000000xx grams give or take 1 decimal place; where xx is the atomic weight of the atom. Chlorine is about 35.5, Carbon about 14; oxygen about 18 and hydrogen about 01. You can check out the actual figures on the net.
Call it PVC which is a multiple of 3 hydrogens and 2 carbons for every chlorine giving 6 atoms weighing in at 56 giving an average weight of
09 or 10.So work out how many atoms of 0.000000000000000001 grams there are in
350 grams.I think its 3,500,000,000,000,000,000 or 35,000,000,000,000,000,000.
But it will be more for canvas or nylon.
name rings a bell, fom my O'level circa 1971
What _precisely_ are you going to do with the answer?
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