MalReynolds

You seem to be assuming that the volume is immediately replaced by the external atmosphere, which I doubt is valid, more likely that the volume of the person would decrease, at least temporarily. The weight of 1 Liter (assuming a massive fart) of air is 1.275g according to wolfram, so, using your density numbers above, 1.275 * 1.06/1.2 = 1.126g lighter. Measurable with a really good scale, if the 90ml fart volume is realistic (has to be more realistic I guess), that’s ~.1g,

Think of yourself as a hot air balloon with a very tiny chamber, and when you release a 90 milliliter fart, you lose a little buoyancy and sink a little. You get heavier when you fart.

No, you get denser, but not heavier.

Flip up ones, as long as you’re not vain (which you aren’t with clipons anyway), solve this problem nicely. Go for polarized, oleophobic too…