Hearing vs Seeing Through Walls

I was wondering why is it that we can hear a person talk inside another room but cannot see him? Do sound waves have any special property that light waves dont?
- Venkat (age 20)
Wichita, USA

There are several differences between sound and light waves that make it possible for sound to be transmitted  from an adjacent room.  Visual light waves are almost totally absorbed by intervening walls whereas some sound waves can penetrate a wall to a certain extent or be carried by supporting beams.   Sound waves have longer wave lengths, meters instead of sub-micro meters for light waves.  A longer wave length will permit more diffraction around a solid object.   

LeeH

(published on 03/21/2009)