Enter the temperature into the calculator below to determine the speed of sound in dry air.
What is the speed of sound?
The speed of sound is the velocity at which sound travels through a medium. That velocity is dependent on the matter or medium it is traveling through. In air, this can be expressed in a simple formula that will be outlined below, but in other mediums it can be more difficult.
The speed of sound is dependent on the molecules in the medium and how they interact with each other. This interaction is directly related to the temperature of the material, and so the speed of sound in anything will be faster in a higher temperature.
Speed of sound formula
The following can be used to calculate the speed of sound in air. Note that air is modeled as an ideal gas here.
c = √(γ * R * T / M)
cis the speed of sound in an ideal gasRis the molar gas constant 8.314,5 J · mol−1 · K−1γis the adiabatic index 1.4 for airTis the absolute temperatureMis the molar mass of the gas. 0.028,964,5 kg/mol (air)
How to calculate the speed of sound in an ideal gas
The following is a step by step guide on how to calculate the speed of sound.
How to calculate the speed of sound in an ideal gas
- First, determine the variables that must be known in order to solve.
In this case, the missing variables are γ and T.
- Next, the values for those variables must be determined
For air, γ , known as the adiabatic index, is equal to approximately 1.4. This value is unit less. The temperature of air is the other variable. For this example we are going to assume the temperature to be 10F.
- The final step is to plug these values into the formula
Enter the values of 1.4 and 10F into the calculator or formula above to get the speed of sound in air at 10F. We find the result to be 323.7 m/s.
- Analyze the results
Check the results for accuracy and apply what has been learned to future problems.
