The Speed of Sound Calculator for Ideal Gases

The speed of sound in an ideal gas can be determined using the following equation:

,

where V_s - speed of sound, R - universal gas constant (8.314 J/(mol K)), T - absolute temperature (in Kelvin), M - molecular mass of the gas (in kg/mol), γ - adiabatic constant of the gas.

By inputting the values of the adiabatic constant, molecular mass, and temperature into the calculator, you can quickly obtain the corresponding speed of sound in the ideal gas.

The default values for the adiabatic constant (1.4) and molecular mass (28.95) are set for dry air. However, you can easily adjust these values to calculate the speed of sound for other gases by selecting the appropriate adiabatic constant and providing the molecular mass.

A monoatomic ideal gas typically has an adiabatic constant of 5/3, while a diatomic gas like nitrogen or oxygen has an adiabatic constant of 7/5. For gases with three-atom molecules, the adiabatic constant is 4/3.

To illustrate, if we consider helium with an adiabatic constant of 5/3 and a molecular mass of 4 g/mol, the calculator reveals that the speed of sound in helium at 20°C is approximately 1007 m/s. This explains why voices sound peculiar or comical when helium is inhaled.

Sound Speed in Gases

Adiabatic constant of gas

Temperature, C

Molecular mass of gas, g/mol

Calculation precision

Digits after the decimal point: 2

Calculate

Speed of sound, m/s

 

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