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The pressure drop shown in the pipe in situation 2 is based on an assumed flow rate, but that flow rate can't be achieved when the pressure is only 50 Pa. You cannot deliver a fixed flow rate and a fixed static pressure: when the flow rate is kept constant, like produced by volumetric pumps, the pressure will vary with resistance: if you block the exit the ...


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When the suction cup presses down it squeezes all the air out, which creates an area of low pressure and sucks the cup in. When you lift the cup the area inside the cup stretches out, and the area of low pressure turns slightly towards high pressure which lets some air out. The air keeps going until the low pressure turns completely to high pressure and cup ...


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How about piping the fan in from another room or basement, thus keeping the fans out of ear reach. There are plastic vent hoses that are easy to manipulate. There are thermo-electric coolers but they are horrible inefficient, but silent.


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Even if you could silently create air flow in multiple directions you would not increase cooling. Temperature is a measure of the random kinetic energy. You would introduce random kinetic energy - not flow. You would actually increase the temperature of the air. Even introducing uniform flow it would eventually convert to random kinetic energy and ...


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I will address your question on how the fan actually works and cools you. @sammy gerbil answered the other part about the noise. I can only add that you probably confuse the fan noise with the whistling in the ears when the wind is strong. Fan creates a flow of air — i.e., increases the speed of the particles in particular direction. Naively, this would ...


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The noise from a fan is mostly the vibrations caused by the fan motor, and the rush of air past the fan blades. You can buy a quieter fan. It will cost more. Some new fans have no moving parts, no blades : http://electronics.howstuffworks.com/gadgets/home/dyson-bladeless-fan.htm The obvious easy way to create an air flow (cross-breeze) without creating ...


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In the presence of a gravitational field the hot air raises because it feels a buoyancy force. There is a difference of pressure between the bottom and the top of the hot air portion resulting in an upward force. If there is no gravity, there is no difference of pressure (in principle) so the hot air does not raise. It just expands uniformly. If you are in ...


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As you points very well, in the lack of gravity there is no hydrostatical separation. I.e. it doesn't matter that the warmer air has a smaller density, there is no gravity which would separate them. But, there are many other effects which would still work, because they aren't caused by the gravity. Most important is the diffusion: Further, in the case of ...


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In thermodynamics. the energy of a body is reflected in its temperature. When a hair dryer heat up its coils, it transfer energy to air molecule via radiation. One of the ways , but not the most efficient of transferring energy is by radiation, which follows the black body curve, both for the heating element and the air. It is very efficient for air ...


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The last sentence is partly wrong - the heavier object does not accelerate faster when coming down; g is identical for both. The drag however, again breakes the lighter object more than the heavier object; but the lighter object start its fall much lower. At the end the winner depends on the parameters. Imagine throwing a steel ball and a ping-pong ball ...


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Here is a simple experimentalist's answer: a) Tin huts in the sun get extremely hot, as anybody who has left a car in the sun will know, much hotter than the outside temperature. b) People in Bangladesh will have about the same IQ as people in other countries, therefore these tin huts will have at least two windows for a cross current in an effor to lower ...


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Without any outlet, under sunlight heat, the temperature inside the house will be high and higher than ambient temperature. The pressure will be high as well. If we keep let air flowing into the house with "eco-cooler", air mass accumulates and the pressure increases until air cannot flow into it. So in order to keep it working, there should be a way to ...


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I can't rule out the possibility that it gets more comfortable inside with the "eco cooler" installed, but the explanation that they give is utter nonsense. They show a thermometer "before" and "after", but they don't tell what the "before" condition was: open window? glass panel? wooden shutter? CuriousOne already hypothesized that it works by blocking ...


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First off, the fact that the board actually blocks the sun light going into the house may have cooled down the house itself (same effect as a solar screen). Since this question is about how the pressure and temperature will be changed after installing the Eco-Cooler air conditioner (the bottle board solely), I will give the following analysis. From the Gay-...


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The temperature is the same either way. It is crucial to remember that your skin feels heat transfer, not temperature. There are two things to consider: Size of opening and amount of hot air: at the same (wind) speed, the current from a large opening will be larger than from a small opening. This means that when you blow breath from a widely open mouth, ...


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Probably wrong, but could it be that your breath is pulling a current of ambient air with it, which could explain why when you open your mouth more to exhale it creates a larger warmer current, and can more effectively insulate from the outside current around it. this could be tested with a thermal camera most effectively. but again probably completely wrong....


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You mentioned: the speed of the air moving through the tube continues to increase greatly when the tube reaches a certain temperature, despite no further increase in temperature. You might have assumed that (as the sun slowly rises) at the time the pipe is fully covered in sunlight, the pipe is immediately at it's maximum temperature. This might not be so, ...


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Sunlight, made up of a mixture of all colors, scatters when it passes between materials, each with a different refractive index, in this case water and air. The water in the river only meets the air at one surface, but the droplets in the air/water mixture contains millions of surfaces. This combination scatters the light more so it appears white overall,...


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Your equation for gas permeation mostly applies to hydrogen, which will dissociate into hydrogen atoms before entering the material. For nitrogen (major component of air), the equation has no square roots. Nitrogen permeation is extremely slow; if the box is welded shut and there are no cracks, then this process will be negligible, even over a 10-year period....



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