The quicker it vibrates, the greater the frequency of sound it produces.
它振动得越快，发出的声音频率就越高。
2
Maybe the ground vibrates, or maybe the ground itself is shifting, tilting.
也许是地面震动了，或者是地面本身在移动和倾斜。
3
So musical instruments evolved in ways that optimize their acoustical properties, how the instrument vibrates and sends those vibration through the air to our eardrums.