Sound
Wavelength of Sound
This is the distance from the crest of one wave to the crest of the next.
Sound is a compression wave in a medium such as air or water. When something makes a sound, the air is compressed in waves that travel from the source in all directions.
When these waves reach your eardrum it vibrates and your brain registers it as sound.
Amplitude
This is the measurement of the degree of change (Positive or Negative) in atmospheric pressure caused by sound waves. That is to say that sounds with greater amplitude will produce the greatest changes in atmospheric pressure when compared to those with a lower amplitude.
Frequency of Sound
When sound waves travel through mediums they sometimes affect the objects they interact with. The Frequency of a sound refers to the number of times an individual particle in a medium vibrates in a certain period of time, most often 1 second. This is different to the speed of the sound, which is measured by how quickly a sound passes a certain point.
Decibels
A decibel or dB is a logarithmic unit used to describe a ratio, for example this ratio may be; power, sound pressure or voltage, it is the unit used to measure the intensity of a sound, the human ear can pick up a huge range of sounds from the slightest near inaudible sound of a finger rushing along skin to the sound of a jumbo jets engines.
The smallest audible sound is 0dB which is close to complete silence and the loudest the human ear can perceive without suffering instantaneous and painful damage is 140 dB however long term exposure to any sound over 80 dB can cause hearing loss.
