Reflection is great. The fact that light bounces off of objects around
us allows us to see them. When light hits a smooth object, it bounces off
much like billard balls off the side of a pool table. When light hits a
rough object, the same thing happens; each different ray of the incident
light is reflected in a different direction.
When a thin beam of light (or "ray") hits a smooth surface, an
interesting law of nature can be observed.
There is an imaginary line that is drawn perpendicular to the surface at the point where the light strikes called a normal. Notice that the angle made by the normal and the incident ray (called the incidence angle) is equal to the angle made by the normal and the reflected ray (the reflection angle). This simple fact is called the law of reflection.