4 ms·

>A study says a mosquito being hit by a raindrop is roughly the equivalent of a human being whacked by a school bus, the typical bus being about 50 times the ma

>A study says a mosquito being hit by a raindrop is roughly the equivalent of a human being whacked by a school bus, the typical bus being about 50 times the mass of a person. That is not a sensible comparison. When you scale something mass changes as the cube of dimension. Strength changes as the square of dimension. So small things are inherently stronger with respect to their mass.

abandonliberty 11y ago
[Citation Wanted] Very believable; how does the math work out?
- troymc 11y ago
  Galileo. Discourses and Mathematical Demonstrations Relating to Two New Sciences. 1638. It's known as the square-cube law. https://en.wikipedia.org/wiki/Square-cube_law https://en.wikipedia.org/wiki/Square-cube_law
  - abandonliberty 11y ago
    Thanks - I hadn't realized that muscle strength was proportional purely to cross section.
- phonon 11y ago
  https://en.wikipedia.org/wiki/Square-cube_law https://en.wikipedia.org/wiki/Square-cube_law
JTon 11y ago
Thanks for the math to back up my own doubt. Fortunately, the bus analogy appears to be added by the author as a bit of sparkle and does not get brought up again.
- lfowles 11y ago
  I think it's a good analogy to have. You don't have the same results from bus:human::raindrop:mosquito, but the size comparison is a useful measure. I didn't realize a raindrop was 50x the mass of a mosquito. I thought they were roughly the same size. Further, it reinforces or introduces the idea (along with the conclusion of the study) that "So small things are inherently stronger with respect to their mass." Lastly, this is National Geographic. Anecdotes and analogies are useful to communicate to the general public.
omginternets 11y ago
>That is not a sensible comparison. Well yeah, since the mosquito evidently survives...
abduhl 11y ago
This is slightly misleading - strength actually changes as the square of the dimension or the cube of the dimension, depending on which strength you're talking about. Axial (tension, compression) and shear strength are derived from net area and so scale with by x^2. Flexural strength is derived from a factored second moment of inertia which happens to work out to x^3.

abandonliberty 11y ago

[Citation Wanted] Very believable; how does the math work out?

troymc 11y ago
Galileo. Discourses and Mathematical Demonstrations Relating to Two New Sciences. 1638. It's known as the square-cube law. https://en.wikipedia.org/wiki/Square-cube_law https://en.wikipedia.org/wiki/Square-cube_law
- abandonliberty 11y ago
  Thanks - I hadn't realized that muscle strength was proportional purely to cross section.
phonon 11y ago
https://en.wikipedia.org/wiki/Square-cube_law https://en.wikipedia.org/wiki/Square-cube_law

JTon 11y ago

Thanks for the math to back up my own doubt. Fortunately, the bus analogy appears to be added by the author as a bit of sparkle and does not get brought up again.

lfowles 11y ago
I think it's a good analogy to have. You don't have the same results from bus:human::raindrop:mosquito, but the size comparison is a useful measure. I didn't realize a raindrop was 50x the mass of a mosquito. I thought they were roughly the same size. Further, it reinforces or introduces the idea (along with the conclusion of the study) that "So small things are inherently stronger with respect to their mass." Lastly, this is National Geographic. Anecdotes and analogies are useful to communicate to the general public.

omginternets 11y ago

>That is not a sensible comparison. Well yeah, since the mosquito evidently survives...

abduhl 11y ago

This is slightly misleading - strength actually changes as the square of the dimension or the cube of the dimension, depending on which strength you're talking about. Axial (tension, compression) and shear strength are derived from net area and so scale with by x^2. Flexural strength is derived from a factored second moment of inertia which happens to work out to x^3.