hardware braces
ginsberg scientific 7 1203 1 lung apparatus plastic
show how the lungs are emptied and filled with air by relaxation and contraction of the diaphragm muscle the chest cavity is represented by a half gallon plastic bell jar with open top and stout rubber sheet which acts as the diaphragm as the diaphragm is pulled downward the atmospheric pressure is lowered inside the chamber causing the lungs to expand taking in air when the diaphragm is released the lungs deflate american educational products have a lead ship time of 21 days sku amed3213