Law of Refraction
Looking at the fish tank as shown, we can see the same fish in two different locations, because light changes directions when it passes from water to air. In this case, the light can reach the observer by two different paths, and so the fish seems to be in two different places. This bending of light is called refraction and is responsible for many optical phenomena.
Source
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"OpenStax College, College Physics. November 10, 2012."
http://cnx.org/content/m42459/latest/?collection=col11406/1.7
OpenStax CNX
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