From: The Butterfly (salsbury_at_bootstrap.sculptors.com)
Date: 05/14/98
Date: Thu, 14 May 1998 10:34:20 -0700 Message-Id: <199805141734.KAA23131@bootstrap.sculptors.com> From: The Butterfly <salsbury_at_bootstrap.sculptors.com> Subject: [nick_at_ece.vill.edu: Re: Domes lighter once built than their component parts? (Need a reference)]
Still looking for the actual reference, but here's some math from one guy
on the GEODESIC list...
------- Start of forwarded message -------
From: Nick Pine <nick_at_ece.vill.edu>
Date: Thu, 14 May 1998 02:07:42 -0400 (EDT)
To: salsbury_at_SCULPTORS.COM
Subject: Re: Domes lighter once built than their component parts? (Need a
reference)
Newsgroups: bit.listserv.geodesic
Organization: Villanova University
>Does anyone remember the reference for how a dome weighs less once it's
>build than its component parts, due to the lifting force of the air mass
>inside it? I think it's probably mainly for larger buildings, like the 450'
>one in Southern California.
I don't recall reading that anywhere, but it makes sense. If the dome
is airtight at the top and warmer and/or more humid than the outdoors,
the air inside will have a bouyant force, like a hot air balloon.
70 F moist air weighs 0.073 lb/ft^3, and 30 F moist air weighs 0.081, and
a 450' hemisphere contains 47.7 million cubic feet of air, so a 70 F dome
might weigh 47.7x10^6(0.081-0.073) = 360K pounds or 180 tons less on an
average 30 F January day in Philadelphia.
Nick
------- End of forwarded message -------
--
Pat
___________________Think For Yourself____________________
Patrick G. Salsbury - http://www.sculptors.com/~salsbury/
Check out the Reality Sculptors Project: http://www.sculptors.com/
---------------------------------------------------------
Here's an experiment to try at home: Every time you take a shower or use the
sink, put the plug in to see how much water you're using.
Then figure out a way to reduce it next time.