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I have learnt that the temperature of something is a direct measurement of the kinetic energies of the molecules in it.

Going by this argument, if the flow speed of fluid is increased in a pipe, and a thermometer measures its temperature with respect to a stationary frame, the thermometer should show an increase in temperature since the net kinetic energy of the fluid has evidently increased.

However, this is not the case. Why so ? Is it that temperature is velocity variant ?

Please feel free to edit the question and improve it.

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If a cold metal object is standing still, and then if we move it, all of its particles gain some energy, kinetic to be precise. All of the molecules gain this energy. But, there is no increase in temperature. Why? Because we connect temperature with the chaotic motion on a molecular level, on the atomic level. This motion of a solid object is on a macroscopic level. Only random molecular motion can induce such motion in something else, eg. in mercury of a thermometer so of course, thermometer wont measure any increase in temperature because all of the particles are displaced in the same direction(meaning, particles of a metal object). So, the same thing with water. This flow of water is an organised motion of a macroscopic number of particles, so this part of energy wont appear as heat. This kind of motion can not induce any feeling of warmth on your skin. Exception is of course, when you bang over and over with a hammer on that same object, that could produce some heat. Some part of energy will be stored in a form of heat and you will be able to measure it with thermometer.

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