Introduction to Wave Motion

Topics: Wave, Wavelength, Standing wave Pages: 3 (931 words) Published: March 27, 2012
Classical physics is comprised of two fundamental models: the particle model and the wave model. Although waves come in various forms, such as undulating water ripples, a vibrating guitar string or witnessing a rainbow, there are certain principles that are common to all waves. Since waves are all around us, the study of wave motion is very old. The Greek Pythagoras, in 550 BC, is often credited as being the first to determine a mathematical expression between length of string, vibration, and the sound produced (Stites, 2003). Later scientists expanded on the wave model, from Galileo, to Boyle, to Newton, to Young. Under this model, waves can be classified of two types: transverse waves and longitudinal waves. In transverse waves, the direction of propagation is perpendicular to the movement of the medium. The medium, for mechanical waves, may be defined as the thing (mechanical, electromagnetic, or otherwise) through or along which the wave propagates. An example would be a wave on a string, or light (electromagnetic waves). However, in longitudinal waves, the medium and wave move parallel to each other. This is the case of sound waves in gases and liquids. Waves can occur in one, two or three dimensions, and consist of alternating crests and troughs, or wave fronts. The principle of superposition describes the effects of two waves that pass each other affect each other or the medium. In brief, the net displacement is the sum of the individual displacement. Once they pass each other, they remain unchanged. An important implication is a further classification of waves. Waves can be described as travelling waves, which show continuous unidirectional motion, or standing waves, which are confined between set boundaries. Standing waves are really two waves identical in frequency f, wavelength λ and amplitude y0 , but moving in opposite directions. Frequency is the number of cycles per second, wavelength is the length of a cycle, and amplitude is the value of...