Interference
Scientific term for the superposition of waves
we consider the 2D case, example: surface of liquids
we assume that there are two sources with the same frequency which oscillate in phase (both sources produce crests at the same time)
superposition--> creates interference patterns
bright regions produced by crests
dark regions produced by troughs
regions with large amplitude (where crest meet crest, or trough meets trough) --> antinodes
regions with little or no amplitude (crest meet trough)--> nodes
the amplitude at a given point depends on the difference in the path lengths from the two sources
if the difference is a an integer multiple of l we have antinode
if the difference is an odd multiple of l/2 we have antinodes
nodes and antinodes form a complex pattern in space
nodal and antinodal lines