Sound barrier demonstration board

A sound barrier demonstration board belongs to the technical field of teaching instruments. The sound barrier demonstration board mainly comprises a sucker, a breather pipe, a piston, sound-absorbingcotton, a vacuum box and a flame-retardant layer. In the invention, the vacuum box is made of a light material, wherein the inner wall of the vacuum box is covered with a layer of adhesive film, and when air in the box is sucked out and seals the box, the interior of the box is in a vacuum state; the sound-absorbing cotton is adhered to the upward side of the vacuum box, approximately hemispherical recesses are densely distributed on the upper surface of the sound-absorbing cotton, the sucker recesses into the sound-absorbing cotton by a certain depth, a round hole is formed in the sucker andconnected with one end of the breather pipe and keeps gas communication with the breather pipe, the breather pipe sequentially penetrates through the sound-absorbing cotton and the vacuum box, and a piston is arranged at the t