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AMPLITUDE, WAVELENGTH, FREQUENCY AND PITCH

AMPLITUDE, WAVELENGTH, FREQUENCY AND PITCH. REVISION. PEAK & TROUGH. Measuring Sound Decibels, hertz, phons, mels and sones can all be used to measure sound levels. Decibels is the most frequently used unit in which sound is measured.

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AMPLITUDE, WAVELENGTH, FREQUENCY AND PITCH

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  1. AMPLITUDE, WAVELENGTH, FREQUENCY AND PITCH

  2. REVISION

  3. PEAK & TROUGH

  4. Measuring Sound Decibels, hertz, phons, mels and sones can all be used to measure sound levels. Decibels is the most frequently used unit in which sound is measured. Decibels are a complicated unit which involves the use of logarithmic formulas. The important thing to remember: Sound is most frequently measured in decibels.

  5. REFLECTION, DIFFRACTION, REFRACTION, Like any wave, a sound wave doesn't just stop when it reaches the end of the medium or when it encounters an obstacle in its path.A sound wave will undergo certain behaviors when it encounters the end of the medium or an obstacle. Possible behaviors include: Reflection Diffraction Refraction

  6. REFLECTION REVERBERATION The reflection of sound waves off surfaces results in either a reverberation or an echo. Reverberation often occurs in a small room. The affect of a particular sound wave upon the brain endures for more than a tiny fraction of a second; the human brain keeps a sound in memory for up to 0.1 seconds. If a reflected sound wave reaches the ear within 0.1 seconds of the initial sound, then it seems to the person that the sound is prolonged. The reception of multiple reflections off of walls and ceilings within 0.1 seconds of each other causes reverberations - the prolonging of a sound.

  7. REFLECTION ECHO Echoes occur when a reflected sound wave reaches the ear more than 0.1 seconds after the original sound wave was heard. If the elapsed time between the arrivals of the two sound waves is more than 0.1 seconds, then the sensation of the first sound will have died out. In this case, the arrival of the second sound wave will be perceived as a second sound rather than the prolonging of the first sound. Resulting in an echo. REFLECTION: Bouncing off an obstacle.

  8. REFLECTION

  9. DIFFRACTION Diffraction involves a change in direction of waves as they pass through an opening or around a barrier in their path. Diffraction of sound waves is commonly observed; we notice sound diffracting around corners or through door openings, allowing us to hear others who are speaking to us from adjacent rooms. Diffraction: Moving through or around an obstacle.

  10. DIFFRACTION Through Around

  11. REFRACTION Refraction of waves involves a bending in the direction or speed of waves as they pass from one medium to another. Refraction, or bending of the path of the waves, is accompanied by a change in speed and wavelength of the waves. So if the media (or its properties) are changed, the speed of the wave is changed. Thus, waves passing from one medium to another will undergo refraction. e.g. Sound travels faster through hot air than cold. Thus it travels faster above the sea than on the sea line. Refraction: The change in speed and size of wave changes as the medium changes.

  12. WAVELENGTH The wavelength of a wave refers to the distance between peaks or troughs. WAVELENGTH WAVELENGTH WAVELENGTH

  13. FREQUENCY The frequency of a wave refers to how often the particles of the medium vibrate when a wave passes through the medium. In mathematical terms, the frequency is the number of complete vibrational cycles of a medium per a given amount of time. MEASURING FREQUENCY The unit for frequency is the Hertz (abbreviated Hz) where 1 Hz is equivalent to 1 cycle/second. If a coil of slinky makes 2 vibrational cycles in one second, then the frequency is 2 Hz. If a coil of slinky makes 3 vibrational cycles in one second, then the frequency is 3 Hz. And if a coil makes 8 vibrational cycles in 4 seconds, then the frequency is 2 Hz (8 cycles/4 s = 2 cycles/s).

  14. FREQUENCY http://www.youtube.com/watch?v=h5l4Rt4Ol7M

  15. AMPLITUDE The amplitude is the maximum positive displacement from the undisturbed position of the medium to the top of a crest. This is shown in the following diagram: It is important to distinguish between positive and negative amplitudes. These displacements are shown in the following diagram: It is the displacement of the medium from its normal position.

  16. PITCH A sound wave, like any other wave, is introduced into a medium by a vibrating object. The vibrating object is the source of the disturbance that moves through the medium. The vibrating object that creates the disturbance could be vibrating string and sound board of a guitar. The sensation of a frequency is commonly referred to as the pitch of a sound. A high pitch sound corresponds to a high frequency sound wave and a low pitch sound corresponds to a low frequency sound wave.

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