### How does Density differ from Relative Density?

##### April 11, 2017

# Difference between Density and Relative Density

###### Density

**Density** is the mass per unit volume. So if we divide the mass of a substance with its volume then we get the density of that substance. Here we get another definition of mass. **Mass=volume X density. **Unit of density in SI is Kg/meter^{3}. So if we say density of ice is 916 kg/meter^{3 }in SI means if we take a slab of ice of unit volume (length=1 meter, breadth = 1 meter and height = 1 meter), and measure its mass then its mass will be 916 kg.Similarly density of water is 1000 kg/m^{3 }means water of 1 cubic meter volume have a mass of 1000 kg.

**Relative Density**

Relative density of a substance is the ratio of its own density and the density of water. It’s a comparative parameter calculated with respect to water’s density. It’s a ratio of two densities and a number only without any unit.

Relative density of water is certainly 1. [Relative density of water = density of water/density of water = 1]

And relative density of ice = density of ice / density of water = 916/1000 = .916

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