SmarterEveryDay
2 HN recommenders · recommended in 3 months, 2019–2023
11:21 · 6.5M views · Dec 28, 2018
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.
Recommended as the clearest footage of a whip tip going supersonic, and cited in shockwave discussions.
3 comments from Hacker News
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
Fun fact, you can accelerate an almost-everyday object to supersonic speeds: whip tip [1,2]. 1. [LINK] 2. this video (very much recommended)
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.