6.5M views · Dec 28, 2018 · 11:21 · 2 HN recommenders · 3 mentions · discussed 2019–2023
Smarter Every Day uses high-speed and Schlieren photography to show how a whip crack is a supersonic shockwave formed at the tip. It references academic papers on whip physics.
Why Hacker News points people here: Recommended as the clearest footage of a whip tip going supersonic, and cited in shockwave discussions.
“I highly recommend it.”HN comment, 2019
“I highly recommend it.”
Old-school Schlieren setup capturing shockwave formation in whip cracks.
As mentioned by others, the photography technique looks like (and apparently is a software enabled variant of) Schlieren photography. This(1) is a neat example of an old school Schlieren set up capturing shockwave formation during whip cracks. I highly recommend it. (1) this video
“(very much recommended)”
Shows a whip tip reaching supersonic speed.
Fun fact, you can accelerate an almost-everyday object to supersonic speeds: whip tip [1,2]. 1. link 2. this video (very much recommended)
“you can observe this effect in the high speed Schlieren footage of a whip in this video”
High speed Schlieren footage illustrating shockwave overtaking disturbance.
Point taken. Thanks for the explanation, that helped me a achieve a deeper understanding & blew my mind. This animation of a tachyon goes well with your explanation: link If you look for it, you can observe this effect in the high speed Schlieren footage of a whip in this video this video (you can skip to around 8 minutes) It starts to disturb the air, then the shockwave overtakes the disturbance, so you can observe them in the flipped order if you're in the sound universe.
