[ExI] Fish in space
pharos at gmail.com
Sat Mar 18 15:58:47 UTC 2017
On 18 March 2017 at 15:22, spike wrote:
>>... On Behalf Of BillK
> Subject: Re: [ExI] Fish in space
> On 18 March 2017 at 13:31, Dan TheBookMan wrote:
>> I'm more curious about what would happen to vertebrates and other
>> macrobes under lunar or Martian gravity, simulated or actual.
> I can give you a fun bit of data: fish can survive 100g for ten minutes.
> There is no documentation because it was illegal. When I was a younger man,
> I was helping set up an experiment on a centrifuge (48 in radius industrial
> centrifuge, the kind few can access) at China Lake Naval Research. I went
> to the pet store, bought a dozen neon tetras (because they are cheap) put
> the hapless characiformes in a thermos bottle, spun them to 100g for ten
> minutes. After they came out, all survived but were swimming in a spiral
> manner like a well-hurled football. Later they seemed to have recovered.
> I have long wanted to repeat that experiment under more favorable
> circumstances, but now I have no access to a centrifuge of that size. I
> don't know how many gs a tetra can endure. Do you?
I don't think you need an industrial centrifuge nowadays. Your kid
could make one out of cardboard and a plastic bag (to hold the water).
The result, which spins at over 300 revolutions per second (rps) and
generates a centrifugal force about 10,000 times that of gravity, is
able to separate blood samples into corpuscles and plasma in less than
two minutes. This is a rate comparable to that of electrical
centrifuges. Spinning such samples for longer (about 15 minutes is
ideal, though that is a lot of effort for a single spinner) can even
separate red corpuscles, which may be infected by malarial parasites,
from white ones, which cannot be so infected.
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