Density 

Oh Density oh density 
the mass to volume ratio 

Oh density oh density
the property that's used to show

Each substance with a purity
is tested with assurity 

Oh density oh density 
the mass to volume ratio 

Oh density oh density 
pure water has a quality 

Oh density oh density 
the ratio is plain to see 

The mass to volume equals one
If you add salt it will have some 

More density more density
the mass to volume ratio