Naked Science Forum
General Science => General Science => Topic started by: Bolvan on 17/06/2017 20:47:22
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Water evaporation vs second law
Water evaporates and makes surface it evaporates from colder compare to ambient. Achieved delta T is enough to run drinking bird, hydro-plants or similar. I do not get it! Did Mr. Clausius see clouds in the sky? Or water did not evaporate when he was confusing civilization postulating his delirium?
I propose simple experiment: take two thermometers, cover liquid containing chamber of one with small piece from napkin and put a drop of water on it. One thermometer will show 25 C. The second will show 21 C.
I wonder where from our hydro-plant do take energy to convert into electrical?
Has Lord Kelvin's heat multiplier been objectively studied? For multiplying ambient heat ( like a lens to run Stirling ), creating delta T to run heat to mechanical converters efficiently, self-startlingly with extra output.
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Your English is a little hard to follow.
Hydroelectric power plants run by extracting kinetic energy from the movement of water, not temperature differences caused by evaporation.
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Where did water take energy from to become cloud, fall down as a rain to become a river to spin hydro-turbine?
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Where did water take energy from to become cloud, fall down as a rain to become a river to spin hydro-turbine?
The Sun.
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Very true! Does water evaporation require direct solar radiation? Will it evaporate at night?
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Very true! Does water evaporation require direct solar radiation? Will it evaporate at night?
No to the first question and yes to the second. Water can achieve net evaporation so long as the atmosphere above the water is not already saturated with water vapor. The energy required still comes from the Sun, since the surface of the ocean would be frozen if the Sun wasn't there to keep it above the freezing point. Heat from the Sun travels by conduction and convection through the atmosphere to keep the Earth warm even at night.
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I propose simple experiment: take two thermometers, cover liquid containing chamber of one with small piece from napkin and put a drop of water on it...
What you have described is a well-known device for measuring relative humidity, using a wet and dry bulb thermometer.
If the relative humidity is 100%, no water will evaporate from the wet bulb, and the two thermometers will read identical temperatures.
See: https://en.wikipedia.org/wiki/Hygrometer#Psychrometer_.28Wet-and-dry-bulb_thermometer.29