Why insulation rockwool can absorb sound?

     Insulation rockwool products are made of a large number of fibers which can form a porous connecting structure, and each hole is connected with each other. If there is molecular friction in the air, the tiny fibers will be mechanically vibrated, which will transform its sound energy into heat energy. It can also be explained in this way that when sound is introduced into insulation rockwool, some of the sound will be reflected back, others will penetrate the rock wool, and some will rub with the components in the rock wool to convert the sound energy into heat energy. The sound will be lost in the rock wool, that is, the sound will be absorbed by the insulation rockwool.
     The sound-absorbing property of insulation rockwool is not only related to the structure, thickness and material, but also related to the incident direction and frequency of sound.