1. ekwhite says

    Very cool video. I hadn’t thought of applying the Reynolds number to the world of bacteria before.

  2. jstackpo says

    And for your homework, go read John Bath’s “Night Sea Journey” found in his book “Lost in the Funhouse”.

  3. ealloc says

    This video is based on a very famous paper/talk by Purcell in 1977, as mentioned at the beginning. The paper is covered in pretty much any intro biophysics course! It has a very casual tone and might be legible to a semi-lay audience too, so check it out if you want more:‎

  4. Trebuchet says

    “Water numbers outnumber you a thousand trillion trillion to one, so pushing past them with your gigantic body is easy” seems like kind of a non-sequitur. Some super-viscous fluid might have the same number of molecules but be difficult to get through. It’s kind of an over-simplification.

    Otherwise, cool video. I didn’t know about sperm tails spiraling, essentially screwing their way to the destination.

  5. ekwhite says

    I mainly use Reynolds numbers when evaluating water systems for prevention of biofilm formation. Reynolds numbers in excess of 20,000 are desirable for water for injection systems. Biofilms are a fascinating topic in themselves.

  6. moarscienceplz says

    I mainly use Reynolds numbers when evaluating water systems for prevention of biofilm formation.

    If the biofilm does form, would it be a Reynolds wrap? ;-p

  7. Amphiox says

    This is also why (one reason among many) proteins like bacterial flagella and kinesins and so forth are not analogous to macro-scale machines and motors (that being a common ID talking point).

  8. dccarbene says

    I am immediately reminded of “Mach 20” from Laurie Anderson’s “United States Live” [disk 4 – back when people still used disks – mine are the big black ones you used to pull a needle across – I think they used to call them “gramophones” or something like that…]
    “Would they realize they were carrying information…”

    [P. S. – speaking of Laurie A.: RIP, Lou Reed]

  9. bognor says

    I’m pretty sure what this video says at ~3 minutes about sperm flagella is wrong. They don’t spin around; they undulate within a plane, a bit like an eel, or a snake on flat ground. Prokaryotic flagella are spinning corkscrews but eukaryotic flagella have a different structure and mechanism.

  10. UnknownEric the Apostate says

    Every time I look at this post, I get “The Penis Song” from Monty Python’s Meaning of Life stuck in my head.

    “…and you won’t… a-come…. a-back.”

  11. PDX_Greg says

    @17, Eric That, and not the “Every Sperm Is Sacred” song from the same movie? That’s just wrong.