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I am wondering how heat loss happens in sound waves through air.

First of all, for wave energy to be transformed into heat, absorption should happen by a medium.

But why wont absorption implicitly translate to faster vibrations which would state that even though wave energy was translated into heat vis absorption, that again must have transfered back into wave energy.

My logic is that some particles that absorb wave energy will in turn increase their their own kinetic energy, and those that dont absorb wont. So some particles will vibrate more, some wont. Then due to this difference between particles, redistribution energy will occur and since particles that absorbed energy, they might not actually vibrate in a pattern but randomly start moving who knows where. I believe this random motion and not in direct vibration pattern is why we say energy of wave was lost due to heat conversion. Correct ? But I wonder why absorption(even though it increases KE of particle) does not implicitly give it more vibration in the same pattern as it had before the absorption ?

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But I wonder why absorption(even though it increases KE of particle) does not implicitly give it more vibration in the same pattern as it had before the absorption ?

At the classical mechanics level, there are no patterns in particular. Th e particles in a gas for example will be randomly scattering off each other and the temperature of the medium depends on their average kinetic energy. There is no pattern to be followed. The acoustic energy will be finally absorbed in the random directions of the particles in the medium and add to the temperature.

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  • $\begingroup$ if there was no absorption, there will definately be a pattern(not at a single particle level, but compression batch pattern moving to the right and to the left after that). This is clear to me. But with absorption, since wave still propagates, then we conclude that there is still a pattern of compression batch (it is just this compression has less KE because heat conversion causes some of the particles in the region to even scatter more in different directions and cancel out some of the particle’s defined direction) hence compression batch still has a pattern but reduced. Is this incorrect ? $\endgroup$
    – Giorgi
    Jun 3, 2023 at 10:01
  • $\begingroup$ if you are talking of a sound wave propagating in the medium continuously, there will be a left over pattern of vibrations on which more incoming can increase the amplitude ,depending on the medium, but the dissipation of the energy into the medium will still be the random kinetice energy directions that add up to the Temperature. $\endgroup$
    – anna v
    Jun 3, 2023 at 15:59

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