
What Do Physics, Bacteria, and Tai Chi Have in Common? - elorant
http://nautil.us/issue/37/currents/bacteria-are-masters-of-tai-chi
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NobleLie
> No microorganism gets to move for free. Newton’s third law, that every
> action has an equal and opposite reaction, becomes something of a tautology,
> for there are no longer any actions.

I acknowledge this post was made by a scientific author catering to the masses
who have little experience with physics but this is misleading and wrong.

 _Nothing_ gets to move for free (according to known laws and our mutual
agreement of what it means to have a 'potential' energy) of course including
microorganisms. He even contradicts himself by earlier stating that the tiny
organisms do move miniscule distances on the order of angstroms, micrometers
etc after they stop "swimming" ( applying a force to the water (abiding by
newtons third law, and thus, swimming.) They _do_ have both positive and
negative accelerations.

Taking into account the micro fraction force and size of these tiny "things"
compared to larger "things" this conclusion just makes a whole lot of
intuitive sense, regardless of ones understanding of Reynolds number

Finally, to get a numerical grasp of how the physics is different for small
Reynolds number, the average ecoli is 2 micrometers, and an angstrom is 0.0004
micrometers which I admit is interesting, since in one of his exemplary cases,
the bacteria only travels 1/5,000 of its average length before stopping,
whereas a human may travel maybe 1/2 body length before stopping, swimming at
~0.5 m/s.

