Re: Density of gas mixture

[Chuck Britton <britton@ODIE.NCSSM.EDU>]

In a similar vein, many people will tell you that cream is 'more
dense' than skim milk! Even those old enough to clearly remember the
cream FLOATING to the top of the unhomoginized milk bottle with
wrestle with the idea(s) of density.

'Surely' thick oil is more 'dense' than water (even tho it floats).  ;-)

In high school I managed to 'figure out' the humid vs dry air
question only after assimilating the idea that a 'mole' of gas at STP
had a certain fixed volume (22 liters?) REGARDLESS of the mix of
molecules. (6.02E23 of ANY combination of 'ideal' atoms/molecules)



> John C. has clearly stated the right answer.
>
> Let me take a moment to analyze the *wrong* answer a little bit also.
>
> I haven't made a scientific study of the abnormal psychology of moist air,
> but my experiences tend to confirm Alvin's report : the wrong opinion is
> widely and often strongly held.
>
> 1) Most people have no way of measuring the quantity physicists call
> density, so for them the word is an abstract, almost metaphorical concept.
> Density may be a metaphor for "resistance" --- in the sense that the
> "sticky" summer air "resists" my efforts to run a marathon.

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Chuck Britton                                   Education is what is left when
britton@odie.ncssm.edu                          you have forgotten everything
North Carolina School of Science & Math         you learned in school.
(919) 286-3366  x224                            Albert Einstein,        1936