Density can be the amount of matter in a given volume, also known as mass density. Density can also be the number of objects in a given volume, known as number density.

Density is calculated by dividing the mass of an object by the volume of the object. The volume of an object can be stated as cubic centimeters or milliliters as both are equivalent.

Water has a density of 1 gram per milliliter. This means that 100 milliliters of water also has a mass of 100 grams. The least dense element on the periodic table of elements is hydrogen with a density of 0.00008988 grams per milliliter.