





Refraction: "The bending of a wave, such as a light or sound wave, as it passes from one medium to another medium of different density. The change in the angle of propagation depends on the difference between the index of refraction of the original medium and the medium entered by the wave, as well as on the frequency of the wave." (per the American Heritage Science Dictionary).
Noise-barrier design: 1970's engineering studies focused extensively on refraction as a method of designing highways' borders with their environment.








