Class 2/4: Waves

In class we went over path difference, interference patterns, and briefly touched on nodes and anti-nodes. Path difference is interference between multiple waves. This occurs due to a difference in the length of the path the waves are traveling. Path difference can either cause constructive interference, when either a peak and a peak meet to create a higher peak or a tough and a trough meet to create a deeper trough, or destructive interference, when the waves are out of phase and cancel eachother out (a peak and a trough combining to cancel eachother out, forming a flat surface). Maximum constructive interference occurs when the path difference is an even number of half wavelengths and maximum destructive interference applies for an odd number of wavelengths. Next, we went over interference patterns. These are symmetrical patterns which occur when sources in the same medium are in phase. The examples given were a puddle of oil in a parking lot appearing rainbow-colored, the feathers on the head of a mallard, and mother of pearl. Nodes are where there is no displacement or amplitude, producing a "smooth area". This is because destructive interference cancels a peak and trough out. Anti-nodes are the oppostive, areas of maximum displacement produced by contstructive interference.