In this video, Steve Spangler says the substance he is using is a poly(ethylene oxide): http://www.youtube.com/watch?v=m-88M75_PCI

He mentions that one molecule would go to the moon and back twice! I have a hard time believing this, but I guess it must be true.. Is it true that poly(ethylene oxide) molecules can be that long?


1 Answer 1


Short answer? Possibly, but these ones aren't.

So, the other thing mentioned in the video is that the specific material he's using has a molecular weight of approximately four million g/mol. If we assume it's ordinary poly(ethylene oxide), we can get the rough number of $\ce{(CH2)2O}$ subunits by just dividing by the molecular weight of the subunit:

  • $(12 \times 2) + (2 \times 2) + 16 = 44$
  • $\frac{4000000}{44} \approx 90900$

So, if we assume that each $\ce{C-O-C}$ back-bone unit is stretched out like a di-methyl ether molecule, a quick check on a fairly standard Ghemical force field gives me a subunit length of approximately 3.7 Å.

  • $3.7 \times 10^{-10}\ \mathrm{m}\times 90900 = 0.00003363\ \mathrm{m}$

So, these molecules should be about 0.03 millimetres long. Not exactly astronomical distances, but impressively long for a single molecule.

In theory, I don't think there's anything stopping you making a molecule as long as they claim, but these ones certainly aren't. I think also that the longest (synthetic) polymers in common use are of similar molecular weights and thus similar lengths: ultra-high molecular weight polyethene seems to top out around 4.5 million g/mol for commercial applications, from a quick search.

Biological molecules frequently get longer than this, though, especially DNA: the average human chromosome apparently contains a single DNA molecule approximately 5 centimetres long.

The man explaining in the video may have erroneously given the figure for the total length of all the molecules in that beaker.

  • 1
    $\begingroup$ Note that a while a millimetre (or kilometre) long molecule is surely allowed, you cannot straighten it out to that lenght. It would long before rupture under its own desire to coil up into a ball, unless it was cooled very close to absolute zero. Entropy rules. $\endgroup$
    – Karl
    Jan 6, 2020 at 7:43

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