# Law of Conservation of Mass

The law of conservation of mass states that matter can neither be created or destroyed. You can mix, separate or rearrange, but the total amount of mass remains the same. An example of this is that all matter that enters a pipe will exit the pipe.

## law of conservation of mass formula

\(\large{ \frac{ \partial \rho }{ \partial t } + \triangledown \; \left( \rho \; v \right) = 0 }\) |

### Where:

Units |
English |
Metric |

\(\large{ \rho }\) (Greek symbol rho) = density | \(\large{\frac{lbm}{ft^3}}\) | \(\large{\frac{kg}{m^3}}\) |

\(\large{ \partial }\) = divergence | - | - |

\(\large{ v }\) = flow velocity field | \(\large{\frac{ft}{sec}}\) | \(\large{\frac{m}{s}}\) |

\(\large{ t }\) = time | \(\large{ sec }\) | \(\large{ s }\) |