That's exactly right. The Beehive House has adobe walls that are thick enough for the coefficient of heat diffusivity of the adobe to have this effect. Other pioneer-period and even later homes were often constructed with adobe walls that are only two wythes (two vertical layers of masonry) thick, or about 10 inches; thus, the process of heat transference in lieu of insulation that you describe isn't as effective. I didn't mean to sound too mocking of those who continue to repeat this myth, such as the Temple Square guides. It takes a high school education to understand that dried mud isn't a good insulator. (Oops, there I go making fun of others again.) I've been to Scotty's Castle, but I don't remember the waterfall. Good idea, though, for several obvious reasons. I also don't remember if the guides there repeated the same story about adobe and insulation, but I'm not surprised. It's a myth not limited to LDS folk - we Mormons just like to add the part about Brother Brigham's genius in suggesting that settlers use adobe to build their homes. Kim -----Original Message----- From: utah-astronomy-bounces@mailman.xmission.com [mailto:utah-astronomy-bounces@mailman.xmission.com] On Behalf Of M Wilson Sent: Monday, December 27, 2010 1:19 PM To: Utah Astronomy Subject: Re: [Utah-astronomy] Straight Dope What I think is meant is that it's going to take a long time for the interrior of a home to heat up when the sun is beating down on it thru an adboe wall. After the sun sets and the outside temperature drops, the adobe wall will then continue to transfer heat to the interior for several hours due to the time lag effect. Thus a well-planned adobe wall of the appropriate thickness is very effective at controlling inside temperature through the wide daily fluctuations typical of desert climates (ie it wont get as hot or as cold inside as it does outside). As far as that goes, I think I've heard the same "insulation" story when visiting Scotty's Castle in Death Valley. Scotty went one step further by having a cascading waterfall as a feature in one of the interrior walls. --- On Mon, 12/27/10, Kim <kimharch@cut.net> wrote: From: Kim <kimharch@cut.net> Subject: [Utah-astronomy] Straight Dope To: "'Utah Astronomy'" <utah-astronomy@mailman.xmission.com> Date: Monday, December 27, 2010, 11:48 AM For anyone who reads the Salt Lake City Weekly you may have already heard of Cecil Adams and his column, The Straight Dope. For fun this morning I perused his website by the same name. I found this gem from 1986: http://www.straightdope.com/columns/read/417/is-the-great-wall-of-china-the- only-manmade-object-you-can-see-from-space. This reminds me of one of my favorite LDS myths (unrelated/off-topic, so dont anyone get offended, please). As a child I was told how brilliant Brigham Young had been to tell the Utah settlers to build with adobe. It was cheap, and according to LDS myth, a great insulator. (This is still being perpetrated by the Blessed Sisters of Temple Square in their tours at Brigham Youngs SLC residence, the Beehive House. Go take a tour if you doubt it. Youll hear other LDS myths, too.) For anyone who cares, and for the record, adobe is NOT an insulating material at all. It would take a 50-inch-thick adobe wall to approximate the insulation value of a typical 2x6 exterior wall in modern construction. Adobes favorable properties as a building material come largely from its thermal mass. I wont bore everyone with details, but if youre interested, heres a good discussion of the thermal properties of adobe: http://www.quentinwilson.com/adobe-as-mass/. FWIW, I live in a house partially built of adobe and my pioneer ancestors built houses of adobe. I am proud of my LDS heritage, even when myths are told about them. Merry belated Christmas to everyone, and Happy New Year. Kim _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.slas.us/gallery2/main.php Visit the Wiki: http://www.utahastronomy.com _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.slas.us/gallery2/main.php Visit the Wiki: http://www.utahastronomy.com ----- No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1191 / Virus Database: 1435/3342 - Release Date: 12/27/10