https://www.thevespiary.org/rhodium/Rhodium/chemistry/wacker.krv.html (https://www.thevespiary.org/rhodium/Rhodium/chemistry/wacker.krv.html)
Consider its density of 1,3 g/ml and compare it with water (1 g/ml).
When doing separations, you will rarely find that that your dcm phase will be 1.3 g/ml and your aqueous phase 1.0 g/ml. If you're looking at these specific gravities in a post-reaction work up sense, you must remember that there's gonna be stuff dissolved in both layers, affecting respective densities.
It makes little difference in the case of dcm/water since their densities are considerable different, but it can in other cases.
If you have (for whatever reason) a product in chlorobenzene (sp 1.105) and you wash it with brine (sp 1.230) then the aqueous layer will go to the botton and the np will stay on top, whereas washing with dh20 will result in the opposite.