Sorry for the cheesy reference to the Zen koan of one hand clapping.
I was trying to get my dog’s attention today and clapped my hands rather loudly. Where I clapped them happened to be very close to Mrs. Call’s ears and she was none too pleased.
But it got me thinking: from whence comes the sound? Please bear with me as I reveal my ignorance of acoustics and the like.
I know that if I record the sound of my clapping and play it back, the sound is reproduced by magnets thrusting a cone of paper in just the right way. This cone pushes a volume of air, and this push propagates as a wave, hits my eardrum causing it to vibrate in kind, and thus I can detect and identify the sound.
Why must my hands make contact to cause the sound? As my hands approach each other, there is (I imagine) a sandwich of compressed air between them. If I could stop short a nanometer before any contact, what if anything would I hear?
Is it that the contact causes my hand/arm to push a larger volume of air than was between my hands?
Quick experiment: :smack: Hmmm, sounds the same…