Air transmits sound through springiness even though it lacks a Young’s modulus

Evidence

So far the speed of sound in solids has been considered. However, sound is more usually considered as something that propagates through air, and for music, this is the normal medium for sound propagation. Unfortunately, air does not have a Young’s modulus, so Equation 1.1 cannot be applied directly, even though the same mechanisms for sound propagation are involved. Air is springy, as anyone who has held their finger over a bicycle pump and pushed the plunger will tell you, so a means of obtaining something equivalent to Young’s modulus for air is Young’s modulus is a measure of the “springiness” of a material. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 66

Categorization

• corroborated: 2 independent passages support this claim — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 66