Editing Refraction (section)

===Water===
{{Main|Water wave refraction}}
[[File:Beach and waves (2784111859).jpg|thumb|Water waves are almost parallel to the beach when they hit it because they gradually refract towards land as the water gets shallower.]]
[[Water wave]]s travel slower in shallower water. This can be used to demonstrate refraction in [[ripple tank]]s and also explains why waves on a shoreline tend to strike the shore close to a perpendicular angle. As the waves travel from deep water into shallower water near the shore, they are refracted from their original direction of travel to an angle more normal to the shoreline.<ref>{{cite web |url=http://www.coastal.udel.edu/ngs/waves.html |title=Shoaling, Refraction, and Diffraction of Waves |access-date=2009-07-23 |publisher=University of Delaware Center for Applied Coastal Research |archive-url=https://web.archive.org/web/20090414215458/http://www.coastal.udel.edu/ngs/waves.html |archive-date=2009-04-14 |url-status=dead }}</ref>