how can i calculate sound absorption? A very easy method for a high school student?

Question

if i calculate the diffence in dB after placing a material in a room, will that help.......??????????

Answer 1

find 2 long tubes. place them end to end and an audio source at one end covered by a known good sound absorber.
measure the sound pressure level at the far end.
then place a layer of the material accross the opening between the two tubes. measure the spl.
those two readings will give you an spl/area absorbtion rating for your material.