system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 how come they say the bag may not inflate but yet oxygen is still flowing? What would cause the apparatus to work but not inflate the bag?
gpt
Basically, the mask is constantly feeding you oxygen, whether you are breathing it in or not. The bag is there to hold extra oxygen if you're not breathing it in as quickly as it's coming in. They mention that your bag may or may not fill (depending on how hard you're breathing) so you don't freak out and think you're going to suffocate if your bag is empty.