Volume

When we ask how big something is, the question is ambiguous. Do you mean how tall the object is? How wide? How heavy? Or how much space it takes up? That last sense of "size" is called volume.

There are several ways of finding the volume of an object that we'll mention here. The first is to calculate the volume, which is possible if the object is a geometric shape for which there is an easy formula. The formulas for the volume of a cube, sphere, prism and cylinder are given in the NASA graphic below. The volumes of more complex shapes can be determined using calculus, but we won't go into all that here.

Another way to determine volume is by its displacement. The object can be submerged in water; because the object occupies space, the water must be pushed aside (displaced). Measuring the volume of the displaced water yields the volume of the object.

ETYMOLOGY: the word volume comes from Latin volumen, a roll of parchment. Later, the word took on the meaning of 'the size of a large roll of parchment.'