If we apply heat to flame to a fork we can feel the heat move along it's length. Put an ice cube on it and the heat is spent moving into the ice melting some of it, therefore the cool feeling that we might mistaken for cold moving, instead it is heat moving into cold. All examples of cooling and warming are one direction. Heat moves, cold does not.
This is the action in the fridge or airconditioner, heat is being moved out and replaced by less heat through gasses that in vacuum vessels boil at lower temperatures than surrounding temperatures. This boiling off of the heat is expended through fins or fans or baths.
The Alaska pipeline sets on permafrost that is kept frozen by pipes into the ground under each foundation. The pipe is a sealed vacuum tube with a little water in it. The degree of vacuum (negative atmosphere) determines when the water boils. Water boils in a vacuum at temps other than 212°f. These are set to boil at temps of the typical permafrost, when winter cold falls below these values the heat syphon moves heat in the permafrost to the cooler air thus freezing the permafrost to a far lower temperature enabling it to get through the summer without thawing and sinking the pipeline.
check out cooling fins on top |
Cold might not exist but 'cool' is forever ...
ReplyDeleteThis reminds me of a misconception that sounds ridiculous but many people swear is true, nevertheless. The idea that hot water will freeze faster than colder water. People that believe this refuse to budge, even after I explain to them what actually happens. NO! They heard this, decided to believe it, nothing can change that now!
ReplyDeleteI have always loved that one. It must be one best critical thinking tests of all times. If it were so, then why wouldn't the opposite work, if your in a hurry to cook pasta for dinner why not fill the pan with ice cubes. Don't you also wonder why ice machine don't boil the water to speed up freezing, thus a smaller unit could produce more ice. Boy are those companies stupid!
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