stationary waves

• when a wave is formed on a fixed string, the wave travels from the point it is formed to the closed end of the string
• when the wave reaches the closed end of the string, it reflects
• after the wave is reflected, two identical waves (having the same frequency, amplitude and wavelength) travel in opposite directions to each other
• when the waves meet, they superimpose (interfere) with each other
• if the waves are in phase, they constructively interfere into a stationary wave
• the amplitude of a stationary wave is twice that of an individual travelling wave
• stationary waves can be produced by any type of transverse wave
• a standing wave pattern can only exist if there is some form of boundary or reflection at both ends of the medium through which the wave is passing
• if waves are in antiphase, they destructively interfere with each other
• destructive interference occurs when two waves have opposite amplitudes
• in destructive interference, the resultant displacement is zero
• standing waves occur on strings, air columns and water pipes
• nodes are formed at points of destructive interference
• antinodes are formed at points of constructive interference
• nodes are points within the amplitude that are of minimum amplitude, and these points remain stationary
• antinodes are points of maximum amplitude, where the wave is at its highest point
• stationary waves store energy as opposed to transferring energy