Naked Science Forum
General Science => General Science => Topic started by: CAT D8H on 19/01/2010 19:21:47
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We all feel wind chill when outside in cold weather, but do things like engines exposed to cold winds suffer cooling below ambient air temperature?
No one i have asked has been able to answer this.
Any body help with this one pls?
Regards
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I believe they do. Obviously they don't "feel" anything, but the chilling effect moving air has on us is because the moving air carries away heat from our exposed skin more rapidly than when the air is still.
So, an object that is hotter than the ambient air will be cooled more quickly when the air is moving over it. This is just as well, otherwise the radiator in your car would not be able to dissipate the excess heat from the engine.
However, once the body reaches ambient air temperature, wind chill no longer applies. Humans continue to feel the chilling effect, because our bodies try to maintain a constant temperature.
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Good answer Geezer. Another extra effect on humans is cooling due to evaporation of moisture from the skin, also enhanced by a moving air mass.
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Good point Graham. I would guess that evaporation will significantly increase the rate of heat loss from human skin, so the surface of an inanimate object at the temperature of a human would experience less wind chill than a human.
Presumably they factor in some rate of evaporation when they determine wind chill equivalent temperatures.