but I do have questions. I can't help it, LOL! I'm a scientist!

(a) I'm pretty sure that fat is actually less dense than water (think about chicken fat floating to the surface in soup, in the fridge, where it solidifies).

(b) where didja get this info from? density issues notwithstanding, I've wondered for a long LONG time about the "whoosh" issue, because it's a real thing that I've experienced my own personal self.