Q.Define Density and explain how it is measured.

Density

            The term density of a substance is defined as mass of substance (m) per unit volume (V). It is denoted by Greek letter ρ (rho). Density is characteristic property of any pure substance. Objects made of a particular pure substance such as pure Gold can have any size or mass but its density will be same for each.

Formula:       ρ =m/V

 Unit: The S.I unit for density is kg/m³.Sometimes dens of substances is given in gm/ cm3

 Measuring the Density

            It is to be noted that there are two ways of finding the density of a substance either

mathematically or experimentally by taking density of water at 4 C as a reference which is sometimesknown as relative density or 'Specific gravity'. It has no unit, it is a number whose value is the same as that of the density in g/cm³

 Formula: relative density =density of substance / density of water