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In response to the question "Why does the OBC gong at 37 degrees F?"

Date: 18 Jun 1997 15:57:21 -0400
From: "David L. Pillars, Jr." <> Subject: Encyclopedia

" Atmospheric pressure also affects the changes in water's physical state. At the sea-level pressure of one standard atmosphere (760 millimeters of mercury), pure water freezes into ice at 32 F (0 C) and boils into steam at 212 F (100 C). Above sea level, where pressure is reduced, water boils at lower temperatures and freezes at higher temperatures."

Excerpted from Compton's Interactive Encyclopedia Copyright (c) 1994, 1995 Compton's NewMedia, Inc. All Rights Reserved

"Important: The temperature warning device does nothing to alter the fact that surface ice can still form at temperatures above 37.5 F, especially on bridges and shade covered road surfaces."

Excerpted from BMW 3 Series owner's Manual (Page 59)

Furthermore, I have consulted with the Physics dept at Grand Valley State University here in West Michigan. After being bounced around the department, I was told that 32 degrees is the freezing point of PURE water at SEA LEVEL. The freezing point of water can vary from 28 degrees (sea water) to as high as 37 degrees. This explains icing of airplane wings in above freezing temps. It also explains why salt is added to roads and ice cream makers, and why the ocean doesn't freeze solid in the arctic as the salt lowers the freezing point of the ice. This is how antifreeze and coolant works in your car. It keeps your radiator from freezing and it keeps the coolant a liquid at high temperatures. If you change the density of water you change its freezing and boiling point.

Also Bridges and over passes are deprived of the natural heat that radiates from the ground, as there isn't any earth beneath them. Last time I checked that was the definition of a bridge, anyway.

David Pillars
96 Alaska Blue Sport

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