Last winter a friend and I found ourselves commenting on that typical metal popping sound that heaters or stoves make as the temperature changes.
I am guessing that the sound is created by expanding and/or contracting metal? Is there a more thorough explanation, or a completely different one?
Also, we just wondered if someone had coined a name for this phenomena (for example, redshift, etc).
My friend says he noticed a webpage once that mentioned ‘subplusoniam shockwaves’ (spelling?) as the name for this, but I can’t find such a term, which may be for something completely different (should it exist).