Quick fact. Ready?
Our lungs are actually elastic. It’s crazy, isn’t it! With every exhalation, our lungs snap back to its smaller size. Even when there is only a little bit of air being stored, they still want to get smaller.
How do they not collapse completely? There is a negative pressure surrounding the lungs that prevents this. This pressure must be kept sub atmospheric, our else the elastic walls of our lungs will give out and possibly collapse!
The human body is amazing, isn’t it.