After goals, the next important thing is the voice.
The human voice is both a wind and a string instrument. For wind instruments (flutes, oboes, trumpets, saxophones), the amount of breath blown in the correct way is what makes the instrument work. In orchestras, wind (flute, sax) is separated from brass (trumpet) for the purpose of classification, but both are operated and activated using breath (which is the wind). For string instruments (piano, guitar, violin), the instrument is activated using the vibration of the strings. For piano, the key strikes the string and makes it vibrate. For violin, it is the bow made of horse’s hair. For guitar, it is the fingers that strike the strings. The thickness, tightness and length of the strings then affects the pitch that it rings out at. It was Pythagoras who determined, for example, that a string that is half the length of another string of the same thickness will vibrate at twice the speed and frequency, which then creates the octave.
But now the voice is both wind and string. The length and thickness of the vocal cords determines the pitch at which the voice sings. Up to a point, this is determined by the effects of testosterone – men have thicker and longer cords than women, which is why they speak lower. But the voice is the one amazing instrument where the length of the cords can be changed by muscles that control it. So the wind (breath) comes up from the lungs and vibrates the cords at a certain number of cycles per second. In the case of the note A, which is classified as the vibration of 440 megahertz, the cords are vibrating 440 times per second to create the sound. When the vibration is spend up to 462 MHz, the sound created is a C. We do this instinctively even when we talk, and talking uses exactly the same principles to create sound.
Read on in part 3 for more.