I was thinking about Newton's Cradle the other day, and I wondered how those collisions actually look like in detail. Which then got me thinking that my understanding of even a basic elastic collision of two macroscopic objects is weak to say the least. Simplified, the two objects could be two rods of a certain length but negligible width, and they simply meet head on. [=======] [=======] I would imagine when they meet, they will compress each other's ends, which will cause a pressure shockwave to propagate through both of them at the specific speed of sound. These shockwaves will probably get reflected at the respective ends etc. It will probably get rather complex pretty quickly, but are there simulations of or SlowMo videos of this, and particularly how it results in such a clean end result of both objects traveling away from each other? I could imagine the two could just as well just "ring" at their respective resonance frequency, wasting a lot of energy that way (and thus no longer being elastic).