DIY model lungs

How to make a lung model with your own two hands.
Equipment: plastic bottle with cap, scissors, stationery knife, 3 balloons, 2 narrow straws, 1 wide straw, adhesive tape, sealant.
Insert two narrow straws into a wide straw and secure with adhesive tape. Trim them to fit the size of the bottle they’ll go in. Then cut the tails off of two balloons and tape the balloons to the ends of the narrow straws. Prepare a plastic bottle: make a hole to fit the large straw in the bottle cap, and cut the bottom off the bottle. Pass the large straw through the hole and seal it in place. Insert the “lungs” through the bottleneck and screw the cap on tightly. To make the diaphragm, put the structure upside down in a glass and stretch another trimmed balloon over the bottom of the bottle. Observe how the balloons in the bottle inflate and deflate as you push and pull on the diaphragm!
The lungs serve as the respiratory organs for humans and many other animals. They extract oxygen from the air and transfer it to the bloodstream. They also expel carbon dioxide. In this experiment, the balloons on the straws act as the lungs, the straws act as the trachea, the bottle serves as the chest, and the balloon at the bottom of the bottle is the diaphragm. When the diaphragm is pulled, the pressure in the bottle becomes lower than atmospheric pressure, and the balloon “lungs” inflate. When the diaphragm is pressed, the processes reverse. Real lungs work similarly: when the diaphragm contracts, the volume of the chest cavity increases and air fills the lungs. Please note that this is a simplified model of the lungs and does not take into account the movement of the intercostal muscles.
Informative experiments await you in the MEL Chemistry subscription!
Safety precautions: Warning! Only under adult supervision