Sound intensity falls with distance due to energy spreading, not absorption

Evidence

As the sound spreads out from a source, it gets weaker. This is not due to it being absorbed but due to its energy being spread more thinly. Figure 1.15 gives a picture of what happens. Consider a half-blown-up spherical balloon that is coated with honey to a certain thickness. If the balloon is blown up to double its radius, the surface area of the balloon would have increased fourfold. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 289

Categorization

• XREF: Connects to my reading on silence and listening: understanding the inverse-square sound spreading makes sense of why quiet natural places cradle sound differently than enclosed rooms.
• corroborated: 2 independent passages support this claim — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 289