Figure 1-13. Absorption of a sound wave
c. Refraction. As it passes from one medium into another, sound changes speed and direction.
As sound travels from air into glass, the speed increases and its direction changes. The denser the
medium, the faster the speed of sound. Sound travels about 1127 feet per second, or 343 meters a
second (fig 1-14 and 1-15).
Figure 1-14. Sound traveling from air to glass