Standing Wave (a fixed end and an open end, 3rd harmonic)
Two counter-propagating traveling waves (the 1st and 2nd waves) form a standing wave (the 3rd wave).
Each point in a traveling wave performs a simple harmonic motion. Adjacent points oscillate out of phase, but no point is stationary at all times.
Nodes in the standing wave: at any given momoent, the displacements of the two traveling waves are always equal in magnitude and opposite in direction, thus forming a node.
The distance between two adjacent nodes is 1/2 the wavelength.
There are 2 nodes in the 3rd harmonic; the length of the string equals 3/4 the wavelength.
The frequency of the 3rd harmonic is 3 times the fundamental frequency for this string.
