[Chemistry] Density is the ratio of mass to volume. A familiar demonstration of density is the attempt to mix water and oil. Oil floats on water because, in addition to not mixing with water, oil has a low density with water. That is, given equal volumes of the two liquids, the oil will have a smaller mass than the water. Density is calculated with this equation.
`d = m/V`
where d is the density, m is the mass, and V is the volume.