It's a myth that the definition of a normal bowel movement is having 1 movement each day because that is not true for everyone. There is no rule for frequency of bowel movements, but the general range is from 3 times a day to 3 times a week.
We investigate the dependence of the stickiness parameters $t_{ij}=1/(12\tau _{ij})$ -- where the $\tau_{ij}$ are the conventional Baxter parameters -- on the solute diameters $\sigma_{i}$ and $\sigma_{j}$ in multicomponent sticky hard sphere (SHS) models for fluid mixtures of mesoscopic neutral particles.
A solid holds its shape and the volume of a solid is fixed by the shape of the solid. Liquid. In the liquid phase the molecular forces are weaker than in a solid. A liquid will take the shape of its container with a free surface in a gravitational field. In microgravity, a liquid forms a ball inside a free surface. Regardless of gravity, a liquid has a fixed volume.