Originally posted by Geistware
I know you have the equation, but I was understanding that the SOS was due to density since sound needs molecules to propagate. The higher the density the faster the speed. That is why sound travels faster at higher elevations and different materials.
The speed of sound in any one ideal gas (like air) depends ONLY on the temperature. The density and/or pressure are immaterial. The higher the temperature, the faster the speed of sound. For air, the specific formula is
a = 20.04 sqrt(T)
where a is the speed of sound in m/s, and T is the air temperature in Kelvin. Paul gave the same equation, but in ratio form relative to sea level values.
A gas other than air will have the same sqrt(T) dependence on the temperature, but the "20.04" constant will be different. Typically, smaller molecular weights have a larger constant, and vice versa. So the speed of sound in helium is considerably larger than in air at the same temperature.