jdemarisj
03-22-2005 08:35:41
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Re: The question is too vague in reply to Bob/Ont, 03-22-2005 03:55:29
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I didn't see the prior discussion, but it doesn't change physics. I've heard similar hot-water, cold-water freezing questions for years. I also know that there is still some degree are argumentation on the matter, even among experts in the field. Due to that situation, we did some "real world" experiments when I was in college studying physics and water science. So, we did some tests of simply putting water in a freezer at various temperatures and container sizes. Hot water does NOT always freeze first, period. Now, take the actual case of hot water pipes usually freezing before cold water pipes do, when side by side and experiencing the same ambient temperature. From what you have said, the hot water actually takes on a memory of its own, and since it is losing heat faster than the cold water pipe at the outset, even once it gets to the exact same temperature at the cold water pipe, it persists with its accelerated rate and freezes first. I don't believe it, and there are many people more knowledgeable then I that also don't believe it. From what I've observed, read, and/or studied - the freezing pipe situation occurs because cold water retains more gas than warmer water - and this situation lowers the freezing point of cold water. In the pipe situation, we conducted a test using 1/2" copper type L pipe, the two pipes parallel to each other and 12" apart. Air temperature was 8 degrees F, and surface temp. of the pipes was checked every 15 minutes. Water was not run though either of the pipes during the test. The cold water pipe cooled down slighty faster than the hot water pipe, but the hot water pipe froze first - this because the water within it had a slightly higher freezing point.
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