Reflection

Sound waves and light waves reflect from surfaces. Remember that they behave just like water waves in a ripple tank. The angle of incidence equals the angle of reflectionreflection: There is a reflection when waves bounce off a surface.

Smooth surfaces produce strong echoes when sound waves hit them, and they can act as mirrors when light waves hit them. The waves are reflected uniformly and light can form images.

The waves can:

• Be focused to a point, for example sunlight reflected off a concave telescope mirror.
• Appear to come from a point behind the mirror, for example a looking glass.

Rough surfaces scatter sound and light in all directions. However, each tiny bit of the surface still follows the rule that the angle of incidence equals the angle of reflection.