(So I tried making these graphs with a newer Microsoft Excel and a newer Microsoft Paint. Boy was that a pain. Overdone antialiasing made it so that I couldn’t even reasonably fill in the points with a particular color on Paint. I guess from now on I’ll just go back to the good ol’ XP versions.)
Anyway, in the following graph, objects with the same mass are on the same shallowly negatively-sloped lines and objects with the same volume are on the same shallowly positively-sloped lines. Mass is measured in grams and volume is measured in cubic centimeters (and density in grams per cubic centimeter) for this graph. Moving directly right means greater mass and lesser volume. Moving directly left means lesser mass and greater volume. Moving up means both greater volume and greater mass. Note, for example, that Uranus has a greater volume than Neptune, but Neptune has a greater mass than Uranus, both of which are both much smaller and much less massive than Jupiter. Note that along a vertical, the difference between the two scales is equal, and since both scales are logarithmic, the difference preserves ratio; specifically, the ratio of mass to volume is density, and thus the resultant horizontal measure is ln Density, and objects along the same vertical have the same density, and the further toward the right the object is, the more dense it is.
In the following graph, I also placed a few reference densities.
These data points are plotted from mass and volume information gathered from Wikipedia.