Mass is a measure of an object s inertia it is directly related to how much substance there is.
Volume is related to the amount of space an object occupies.
Note, however, that objects occupying the same volume need not have the same mass for example, two equal sized objects made out of lead and wood will have different masses. Between mass and weight mass is more fundamental since the mass of an object is always the same whereas its weight can vary depending on which planet it is on. An object with mass doesn t always have weight for example if it is in deep outer space far removed from any massive body. An object with weight, however, does have mass. It turns out that the gravitational force of attraction acts on all bodies with mass.