system
Given the following post, respond as if you're commenting on Reddit:
human
When we pop a joint like a knuckle or our back, its a realeases air. Where does that air go?
gpt
It dissolves back into the fluid. When you pop your knuckles, you're decreasing the pressure enough to allow the gas to escape the solution, which creates the popping noise. When you decrease the pressure again, it dissolves again. Think of a soda can; when you open the can you decrease the pressure and the gas escapes forcefully, creating a noise.