In this page, we will learn about mechanism of sound.

  Mechanism of Sound

As we have learned in the previous section, sound is waves. So the vibration of sound can be pictured as waves on a machine called an oscilloscope or on computer. Here we will make use of a waveform display softwave, SoundEngine Free(

Please look at the chart on the left. If you input some sound, the waveforms are displayed in blue.To enlarge the waveforms.

An enlarged view of the waveforms.

The vertical line shows the amplitude and the horizontal line shows the frequency, or the number of vibrations per second. The nnit of frequency is Hertz(Hz). The chart above shows that the sound has three vibrations per second, that is 3Hz.The length of each vibration is called wavelength.
The amplituide and frequency are closely connected to the volume and pitch of sound. The volume is larger as the amplitude is larger.The pitch of sound is higher as the frequency is larger.. In the case of a monocord, if you play strongly the string, the amplitude is big and the volome is large. If the string is short, thin, and stretched hard, the frequency is big and the pitch is high. If you remember the video clip in the section of "The Basic Nature of Sound", the higher the pitch, the larger the frequency.
Let's look at the waveforms of sound with the sound in the following clip. We will compare the different waveforms between high pitch and low pitch.


Volume adjustment is recommended, especially in the latter harf!
Through on the clip above
As the volome of the tuning fork kecomes smaller, the amplitude gets shorter. The waveforms are very different between 100Hz and 1000Hz. 100Hz has smoother waves while 1000Hz has rougher waves. The chart below shows the difference more clearly.

In the next section, we will deal with an experiment on the pitch of sound.
for Summary
・Vibrations of sound are shown as waveforms.
・The length of one waveform is called wavelength.
・The volome of sound is related to amplitude and it is larger if amplitude is bigger.
・The pitch of sound is related to frequency and it is higher if frequency is larger.
・In the case of a monochord, if you play strongly the string, the volume is bigger.
・In the case of a monochord, if the string is shorter, thinner, and stretched harder, the pitch is higher.
                               ↑Mechanism of SoundA

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