What happens to particles in soundproofing?

Answer 1

The effect of soundproofing -- any means of reducing the sound pressure with respect to a given sound source and receptor -- on particles depends on the state of the particles. Soundproofing reflects or absorbs the energy of sound waves that transforms into vibrational energy, thus reduces the vibration and its resultant effects.

For particles in the gaseous state, reduced vibration from soundproofing decreases the energy transferred to the free, widely-spaced gas molecules, thus lessening the resultant fluctuation in motion of the gas molecules. As for particles in the liquid and solid state, reduced vibration from soundproofing has a different effect on the particles.

In liquids, energy of vibration transferred to the molecules are mostly absorbed by the intermolecular interactions and bonds (e.g., hydrogen bonding between water molecules). In solids, energy of vibration transferred to the molecules are absorbed by the chemical bonds between the particles of the solid. Thus, for both liquids and solids, soundproofing reduces the amount of energy absorbed by the particles.