Editing Refraction (section)

===Sound===
{{Main|Refraction (sound)}}
In [[underwater acoustics]], refraction is the bending or curving of a sound ray that results when the ray passes through a [[sound speed gradient]] from a region of one sound speed to a region of a different speed. The amount of ray bending is dependent on the amount of difference between sound speeds, that is, the variation in temperature, salinity, and pressure of the water.<ref>{{cite book
 |title     = Navy Supplement to the DOD Dictionary of Military and Associated Terms
 |date      = August 2006
 |publisher = [[United States Navy|Department Of The Navy]]
 |url       = https://www.nwdc.navy.mil/Documents/NTRP_1-02.pdf
 |id        = NTRP 1-02
}}{{dead link|date=April 2025|bot=medic}}{{cbignore|bot=medic}}</ref>
Similar [[acoustics]] effects are also found in the [[Earth's atmosphere]]. The phenomenon of [[refraction of sound]] in the atmosphere has been known for centuries.<ref>[[Mary Somerville]] (1840), ''[[On the Connexion of the Physical Sciences]]'', J. Murray Publishers, (originally by Harvard University)</ref> Beginning in the early 1970s, widespread analysis of this effect came into vogue through the designing of urban [[highway]]s and [[noise barrier]]s to address the [[meteorological]] effects of bending of sound rays in the lower atmosphere.<ref>{{cite journal|doi=10.1007/BF00159677|title=Analysis of highway noise|year=1973|author=Hogan, C. Michael|journal=Water, Air, & Soil Pollution|volume=2|pages=387–392|issue=3|bibcode=1973WASP....2..387H|s2cid=109914430}}</ref>