Let's see characteristics of wave type

  Method of Sound Transmission

When a sound source vibrates, it causes the air nearby to vibrate and the vibration of air passes on one after another. This is how sound transmits. Sound transmission is transmission of vibration, rather than the movement of air itself. This phenomena is called sound wave.(cf."The basic nature of Sound")

Let’s watch how sound transmits when a sound source vibrates.

Thoughts on the video clip
We have used an oscillator as the sound source and put an eraser on its speaker. We hope you have confirmed how the vibration of the sound source transmits through the speaker to the eraser and that is why the eraser shakes. When the volume of sound increases, the eraser’s way of tremble changes and we will explain about it later, in the section of “Mechanism of Sound.” We have used an eraser this time, but many other things can be used for this experiment.

Let’s move on to the next experiment related to sound transmission.
We used two tuning forks and do an experiment as follows:
@ Ring one of the tuning forks (right one).
A Stop the sound of the first tuning fork.
B Check the other tuning fork (left one).

What is resonance? What you just watched is resonance. Resonance is one of the phenomenon of sympathetic vibrations. This experiment shows that the sound/vibration of the right tuning fork causes the vibration of the air around it and that the sound wave transmits in the air and arrives at the other tuning fork, which brings about the vibration/sound of the left tuning fork. In addition, in this case, the natural frequencies of both tuning forks are equal. So the frequency of sound wave transmitted from the right one to the left one overlaps the natural frequency of the left one and this makes the resonance and the bigger sound.

For Summary
・The vibration of sound source causes the air around it to vibrate and this transmits one after another. This phenomenon is called sound wave.
・Resonance: When there are two sound sources with the same natural frequency, the vibration of the first one transmits in the air and arrives at the other and causes the vibration of the second one. This is resonance.
                               ↑Range of Sound

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