Water, air, and glass are example of?

Water, air and glass are the example of Refraction of light.  

Explanation:

Water, air, and glass are involved in the Refraction of light. When light travels from low dense to high dense, the light will get bent or get refracted.For example, in a dark room, there are three glasses filled with water and a small mirror in one glass. When light is torched directly into the glass, it strikes the water straight on and no bending occurs leaving a straight line to the bottom of a glass.Now when light is torched into a glass at a certain angle, it gets refracted due to the passage of light from the air (less dense) to water (high dense). Now place a mirror at the bottom and pass a light at a certain angle. Initially, the light gets refracted while entering the water and then gets reflected due to the mirror, gets bent away from normal as it passes from water to air.