Changes

*Interference: The addition of two or more waves to form a new wave pattern.

*Interference: The addition of two or more waves to form a new wave pattern.

*Diffraction:  The bending of waves around small obstacles and the spreading out of waves when they pass small openings.

*Diffraction:  The bending of waves around small obstacles and the spreading out of waves when they pass small openings.

*Poarization: Describes the orientation of the oscillations of the electromagnetic waves.

*Polarization: Describes the orientation of the oscillations of the electromagnetic waves.

== Modern optics ==

== Modern optics ==