What is said of these bent rays?
They are said to be refracted.
What is meant by refraction?
Bending a ray of light, as it passes from one substance to another of different density; as from air to water, or from water to air.
Where may we see an example of refraction?
In the rays of light from a rod which has one end in the water.
Fig. 7.
Why does the rod appear to be bent?
Because light coming from the part of the rod under the water, is refracted or bent at the surface of the water, while the light from the part above the surface, comes in straight lines to the eye; hence, the rod appears to be bent at the surface, as is represented in [Fig. 7].