Re: $2 a kilogram ?

[Herbert H Gottlieb <herbgottlieb@JUNO.COM>]

Thanks for your well-worded, easily-understandable
response below.

Herb

On Sun, 10 Feb 2002 10:45:23 -0800 John Mallinckrodt
<ajmallinckro@CSUPOMONA.EDU> writes:
> On Sun, 10 Feb 2002, Herbert H Gottlieb wrote:
>
> > ... why does Macy's fill their Thanksgiving Day parade
> > balloons with helium under a pressure that is greater than the
> > atmospheric pressure?
>
> In order to give them some rigidity.  Fortunately it only takes a
> tiny bit of overpressure ("gauge pressure") to do that *secondary*
> job.  As a result the helium is not appreciably more dense than it
> is at atmospheric pressure and it still easily manages to do its
> *primary* job which is to displace air without weighing very much.
>
> John Mallinckrodt      mailto:ajm@csupomona.edu
> Cal Poly Pomona          http://www.csupomona.edu/~ajm


Herb Gottlieb from New York City
(Where it's nice to live but I wouldn't
want to be a tourist here)
herbgottlieb@juno.com