This article ran in The Textbook Letter for July-August
1991.
It accompanied a review of Physical Science: The Challenge of
Discovery, a middle-school book sold by D.C. Heath and
Company.
Down in the Mud with Mark A. Carle
William J. Bennetta
Page 182 of Physical Science: The Challenge of Discovery has
a boxed item headlined "Technology: Then and Now":
What have the Hopi and Zuni Indians known for a long time that
other people are just learning today? These Native [sic]
Americans have built homes with sun-dried clay called adobe. The
adobe homes remain warm in the winter and cool in the summer. Today
scientists at Illinois State University and Argonne National
Laboratory are using the Indians' idea to help other people find a
way to conserve energy. The scientists dug a 12-foot-deep pit under
a house and filled it with mud. Tubing that contained antifreeze
was placed throughout the pit. In the winter, they found that the
antifreeze was able to reduce the rate at which the mud in the pit
froze. In the summer, the melting mud helped to cool the house.
The scientists think their mud pit could cut summer cooling costs by
90 percent in the Northeast, Midwest, and other areas of the United
States that freeze during the winter. Their idea is not new, but
their ability to apply technology in a new way may be helpful in the
future!
We could not understand any of it. What was that first paragraph
about? Did it mean that, until today, only Indians have known how
to build houses with sun-dried clay that bore a particular Spanish
name (adobe)? Or did it mean that, until today, only Indians
have known how to build houses with sun-dried clay, no matter what
the sun-dried clay may have been called? Did Heath's writers not
know that construction with unbaked clay has been practiced in
every part of the world where rainfall is scant and summers are hot?
As for the second paragraph: We could not discern what really was
going on in the mud-filled pit, but it seemed to involve storing and
then recovering energy as the water in the mud alternately froze and
thawed. In other words, it seemed to exploit water's high heat of
fusion. But what did this have to do with Indians or with houses
made from sun-dried clay? The temperature-moderating effects of
dried clay proceed from its low thermal conductivity, not from any
changes in state. Besides blurring some simple physics, Heath's
baffling analogy appeared to patronize the Indians: They seemed to
have been dragged into the story for no reason except to supply a
clever-aborigines anecdote that Heath's writers presumably found
amusing.
On 3 July we sent a query, by certified mail, to Mark A. Carle, the
first of three authors listed on the title page of Heath's book.
(Carle is identified there as "Director of Curriculum Development,
Science Department Chairperson, University School, Hunting Valley,
OH.") We asked him to clarify the first paragraph of the item in
question, to send copies or full citations of the technological and
historical literature on which that paragraph was based, and to send
copies or full citations of the technical literature from which the
mud-pit story was derived.
We sent our inquiry again, by certified mail, on 29 July. At this
writing, we have not received any reply. We still do not understand
the mud-pit story, and we are unable to cite any reason for thinking
that it has a basis in fact.
William J. Bennetta is a professional editor, a fellow of the
California Academy of Sciences, the president of The Textbook
League, and the editor of The Textbook Letter. He writes
often about the propagation of quackery, false "science" and false
"history" in schoolbooks.
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