For sound waves in a fluid (for example air or water) the speed is determined by v=(B/ρ)1/2 where B is the bulk modulus or compressibility of the fluid in newtons per meter squared and ...For sound waves in a fluid (for example air or water) the speed is determined by v=(B/ρ)1/2 where B is the bulk modulus or compressibility of the fluid in newtons per meter squared and ρ is the density in kilograms per cubic meter. The amount the speed changes is given by the index of refraction n=c/v where c is the speed of light in a vacuum and v is the speed in the medium.
