# Density

Written by Jerry Ratzlaff. Posted in Fluid Mechanics

Density (DENS) more precisely volumetric mass density (mass density), is the ratio of the amount of matter in an object compared to its volume. A small, heavy object, such as a rock or a lump of lead, is denser than a larger object of the same mass, such as a piece of cork or foam.

Depending on its density determines whether or not oil will sink or float on water.  Density can also be expressed as specific gravity, which is the ratio of the density of the substance as compared to a reference material at a standard set of conditions.

To calculate the weight density see weight.

## formula

$$\rho = \frac{m}{V}$$

Where:

$$\rho$$ (Greek symbol rho) = density

$$m$$ = mass

$$V$$ = volume

Solve for:

$$m = \rho V$$

$$V = \frac {m}{\rho}$$