Zamień jednostki gęstości: 800 kg/m3  :  na "g" i "cm3" 1,2 g/cm3  : na "kg" i "m3"  

800kg/m^3=(800*1000g)/(100cm *100cm *100cm)=(8*10^5g)/(10^6cm^3)= =0,8 g/cm^3 1,2g/cm^3=(1,2 *0,001kg)/(10^-6m^3)=(1,2*10^-3kg)/(10^-6m^3)=1,2 *10^3kg/m^3= 1200kg/m^3