Homework in Performance Techniques Essay Example for Free

Homework in Performance Techniques Essay Sound Waves- A sound wave is the pattern of disturbance caused by the movement of energy traveling through a medium (such as air, water, or any other liquid or solid matter) as it propagates away from the source of the sound. The source is some object that causes a vibration, such as a ringing telephone, or a persons vocal chords. The vibration disturbs the particles in the surrounding medium; those particles disturb those next to them, and so on. The pattern of the disturbance creates outward movement in a wave pattern, like waves of seawater on the ocean. The wave carries the sound energy through the medium, usually in all directions and less intensely as it moves farther from the source. Prequency and Wave Length In physics, the wavelength of a sinusoidal wave is the spatial period of the wave—the distance over which the waves shape repeats.[1] It is usually determined by considering the distance between consecutive corresponding points of the same phase, such as crests, troughs, or zero crossings, and is a characteristic of both traveling waves and standing waves, as well as other spatial wave patterns. [2][3] Wavelength is commonly designated by the Greek letterlambda (ÃŽ »). The concept can also be applied to periodic waves of non-sinusoidal shape.[1][4] The term wavelength is also sometimes applied to modulatedwaves, and to the sinusoidal envelopes of modulated waves or waves formed by interference of several sinusoids.[5] The SI unit of wavelength is the meter. Reverberations Reverberation is the persistence of sound in a particular space after the original sound is removed.[1] A reverberation, or reverb, is created when a sound is produced in an enclosed space causing a large number of echoes to build up and then slowly decay as the sound is absorbed by the walls and air.[2] This is most noticeable when the sound source stops but the reflections continue, decreasing in amplitude, until they can no longer be heard. The length of this sound decay, or reverberation time, receives special consideration in the architectural design of large chambers, which need to have specific reverberation times to achieve optimum performance for their intended activity.[3] In comparison to a distinct echo that is 50 to 100 ms after the initial sound, reverberation is many thousands of echoes that arrive in very quick succession (.01 – 1 ms between echoes). As time passes, the volume of the many echoes is reduced until the echoes cannot be heard at all. Refraction Refraction is the change in direction of a wave due to a change in its speed. It is essentially a surface phenomenon . The phenomenon is mainly in governance to the law of conservation of energy. The proper explanation would be that due to change of medium, the phase velocity of the wave is changed but its frequency remains constant. This is most commonly observed when a wave passes from one medium to another at any angle other than 90Â ° or 0Â °. Refraction of light is the most commonly observed phenomenon, but any type of wave can refract when it interacts with a medium, for example when sound waves pass from one medium into another or when water waves move into water of a different depth. Refraction is described by Snells law, which states that for a given pair of media and a wave with a single frequency, the ratio of the sines of the angle of incidence ÃŽ ¸1 and angle of refraction ÃŽ ¸2 is equivalent to the ratio of phase velocities (v1 / v2) in the two media, or equivalently, to the opposite ratio of the indices of refraction (n2 / n1): Diffraction- Diffraction refers to various phenomena which occur when a wave encounters an obstacle. Italian scientist Francesco Maria Grimaldi coined the word diffraction and was the first to record accurate observations of the phenomenon in 1665.[2][3] In classical physics, the diffraction phenomenon is described as the apparent bending of waves around small obstacles and the spreading out of waves past small openings. Similar effects occur when light waves travel through a medium with a varying refractive index or a sound wave through one with varying acoustic impedance. Diffraction occurs with all waves, includingsound waves, water waves, and electromagnetic waves such as visible light, x-rays and radio waves. As physical objects have wave-like properties (at the atomic level), diffraction also occurs with matter and can be studied according to the principles of quantum mechanics. Passive Absorption- According to this theory ions are absorbed by the root along with mass flow of water under the influence of transpiration. This theory failed to explain the salt accumulation against osmotic gradient. An increase in transpiration pull increases the uptake of ions by the roots. The uptake of ions by free diffusion. Thus, mass flow of ions through the root tissues occurs due to transpiration pull in the absence of metabolic energy.