So, I have a solution script that predicts how much the volume of a fluid will change as a function of z ... this is a magma expanding as gas in solution is depressurized, if that problem sounds strange. :) Now, the REST of my problem is that this magma is filling a tall, thin ellipsoid stretching from z = 6000 m (depth in the Earth) to z = 800 m at some rate Q such that the volume of magma in this ellipsoid (which expands like a balloon to be the size of the magma) at any given time = Q * t (where t = time the magma has been running intp the system. I'd like to write a script that describes the expansion of that final volume (Q * t) over the depth using the first solution, which is ... (dV% = density_1/density_2) density_2 = density_gas/mass_frac_of_gas + density_water/mass_frac_water + density_1/mass_frac_magma ... I guess what I want is a graph showing total change in volume over time at some given Q, taking into account expansion as a matter of depth and the geometry of this ellipsoid spread out over that depth. I am just exhausted this week and even though I know there is a straightforward solution, I don't seem to have the available brain cells to put it together. Ideas?