[fennecfoxy]

Argon gas does not conduct heat as well as air, so it's an excellent insulator. <--- why it's used for double glazing in housing, to insulate heat transfer.

Which is interesting because the density of argon is greater than air, it does not block or insulate against sound other than the general deadening effect you'd get from multiple layers (energy loss in kinetic transfer from gas to glass to gas to glass to gas again).

Vacuum, He or H would've been better imo