system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:why does it sound different when cold water is flowing out of the faucet than when the water is hot?
gpt
Normally, a water heater has a lot of piping. Pushing the water through this extra piping takes pressure away from the water.

So the water is pushed out of the tap with less force, so the sounds it makes is different.

In addition, heated water often has air bubbles in it. You can see this because they make the water slightly cloudy. Air bubbles absorb sound and allow the water/gas mix to compress or expand slightly. This also changes how the tap sounds.