And thus #rho# has typical units (for chemists) or #g*mL^-1# or #g*cm^-3#...and materials whose densities are greater than that of LIQUID water, i.e. #(>1*g*mL^-1)# do not experience the buoyant upward force from the water sufficient to enable flotation. And this means for given materials, we can assess buoyancy in a given fluid, by assessing the densities.
And so let us put some numbers in..
#rho_"substance"="mass"/"volume"=(157*g)/(412*cm^3)=0.381*g*cm^-3#.
AND since in water a #1*cm^3# block of stuff DISPLACE a #1*g# mass of WATER, there is a net buoyant upwards force, and the stuff will float.
How can this principle be applied to the principle of hot-air, or helium-filled balloons?
