On 5/22/2022 8:43 PM, henh...@gmail.com wrote:
> pls wait 10 years before posting an Answer !
>
> ____________________________
>
> Two glasses of water with an ice-cube in each.
>
> All the conditions are the same in the two
> (volume, mass, temperature ...)
>
> --- except ... one of the glasses has very salty water.

Just a nit-picky follow-up: One molecule of water weighs (about) 18u,
while one of salt weighs about 58.5u. So, if the solutions in the two
glasses have equal mass, it means that for every 4 skillionths of a mole
of NaCl added you must remove 13 skillionths of a mole of water. It
would seem an astonishing coincidence if the solutions' volumes were
to come out equal, at equal temperature.

Or to put it another way: Salt water is denser than pure water of the
same temperature, so if the volumes are equal the masses cannot be,
and vice versa.

(I have long forgotten nearly all the chemistry I once knew, but even
when I still knew it my knowledge wasn't enough to let me calculuate the
abundances of H2O, H+, HO-, NaCl, Na+, and Cl- in either solution, never
mind the more exotic combinations that might crop up fleetingly. And
even if I knew their amounts, I still wouldn't have known how to figure
the density. But "salt water is denser" has remained with me, even if a
facility with equilibrium reactions has not.)

--
esosman@comcast-dot-net.invalid
Look on my code, ye Hackers, and guffaw!

On Thursday, August 4, 2022 at 8:40:18 AM UTC-7, Eric Sosman wrote:
> On 5/22/2022 8:43 PM, henh...@gmail.com wrote:

> > pls wait 10 years before posting an Answer !
> >
> > ____________________________
> >
> > Two glasses of water with an ice-cube in each.
> >
> > All the conditions are the same in the two (volume, mass, temperature ...)
> >
> > --- except ... one of the glasses has very salty water.

> Just a nit-picky follow-up: One molecule of water weighs (about) 18u,
> while one of salt weighs about 58.5u. So, if the solutions in the two
> glasses have equal mass, it means that for every 4 skillionths of a mole
> of NaCl added you must remove 13 skillionths of a mole of water. It
> would seem an astonishing coincidence if the solutions' volumes were
> to come out equal, at equal temperature.
>
> Or to put it another way: Salt water is denser than pure water of the
> same temperature, so if the volumes are equal the masses cannot be,
> and vice versa.
>
> (I have long forgotten nearly all the chemistry I once knew, but even
> when I still knew it my knowledge wasn't enough to let me calculuate the
> abundances of H2O, H+, HO-, NaCl, Na+, and Cl- in either solution, never
> mind the more exotic combinations that might crop up fleetingly. And
> even if I knew their amounts, I still wouldn't have known how to figure
> the density. But "salt water is denser" has remained with me, even if a
> facility with equilibrium reactions has not.)
>
> --
> eso...@comcast-dot-net.invalid

> Look on my code, ye Hackers, and guffaw! <------ which recent movie does this remind me of ?

( hint: suspension of disbelief )

thanks.... when i first saw your nit-picky follow-up... the 1st thing that came to my mind was
the Snoopy-esque rebuttal that .... that's like saying...

[ Dropping 2 identical metal balls ] (on somewhere on Earth) question is invalid
because the gravity would be slightly different for the 2 balls.

__________________________

>>> You don’t need a PhD in altitude-ology to know that running long distances at a higher elevation is more challenging than doing so at sea level. And chances are, you also don’t need a masters degree in maps to know that the southwestern state of New Mexico is fairly mountainous.

This weekend’s USATF Indoor Championships are being held in Albuquerque, NM and at an elevation of 5,312 feet. Regardless of your highest level of educational attainment, go ahead and put two-and-two together: we can expect the distance races (the mile & two-mile) to be a tad slower. But by how much? And what about non-distance events? How will the altitude impact their results?

Well, fortunately for all of us, Citius Mag’s in-house stat-master, graph-maker and armchair-physicist, Dr. Scott Olberding knows a thing or two about track & field as well as conveying information in easy-to-digest chart form.

You’ll notice that distances below approximately 400 meters actually see improvements in their marks when altitude is introduced into the equation. You sea level-dwellers probably don’t realize it, but drag (or air resistance) constantly hampers your ability to be your best self. At higher altitudes, there is less drag (the product in the equation) due to lower air density (our variable).

https://en.wikipedia.org/wiki/Long_jump

-------- i thought (diff in) gravity was the big factor.... is [air density] a bigger factor ?