# What is the sound of two hands clapping? **URL:** \ **Category:** Factual Questions\ **Created:** [July 25, 2005, 3:44am UTC](https://boards.straightdope.com/t/what-is-the-sound-of-two-hands-clapping/314000 "2005-07-25T03:44:26Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![Nature\_s\_Call](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/nature_s_call/32/19006_2.png) [@Nature\_s\_Call](https://boards.straightdope.com/u/Nature_s_Call)\ **Post date:** [July 25, 2005, 3:44am UTC](https://boards.straightdope.com/t/what-is-the-sound-of-two-hands-clapping/314000/1 "2005-07-25T03:44:26Z")
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… ---
**Author:** ![scm1001](https://avatars.discourse-cdn.com/v4/letter/s/c4cdca/32.png) [@scm1001](https://boards.straightdope.com/u/scm1001)\ **Post date:** [July 25, 2005, 10:14am UTC](https://boards.straightdope.com/t/what-is-the-sound-of-two-hands-clapping/314000/2 "2005-07-25T10:14:45Z")
my wag is that until your hands are about to collide the air is poushed out slowly. However at the moment of collision the air is pushed out almost supersonically causing a crack