system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What’s happening inside a chicken egg that makes it float differently depending on how fresh it is?
gpt
There is an air bubble inside the egg, which is small when the egg is freshly laid. As the egg gets older and starts losing moisture, that air sac inscreases in size, until it is large enough to make the egg buoyant.