> Does anyone know an approximate density for liquid soap (i.e. palmolive dishwashing liquid)?

Well, how approximate is okay?

I just took a 2L bottle of "Jergens Skin Care Antibacterial Plus" liquid soap and stuck it on bathroom scale. It wasn't a full bottle; I estimate 350 mL has been removed from it. The bathroom scale read 5 lb.

So that's 5 lb / 1.65 L (2L - 0.35 L). Since 1 lb = 0.45359237 kg, that's about 2.268 kg / 1.65 L, or about 1.37 kg/L (about a third more than the density of water).

I then did another experiment. I took some of this liquid soap and dumped it in water. It sunk to the bottom, but not really fast. The density must therefore be somewhat greater than 1 kg/L (the density of water). The figure 1.37 kg/L is therefore likely to be about accurate.

Why do you need to know this, by the way?

-SB