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How does a whip break the sound barrier? (Slow Motion Shockwave formation) - Smarter Every Day 207

Name: How does a whip break the sound barrier? (Slow Motion Shockwave formation) - Smarter Every Day 207
Description: 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.

SmarterEveryDay Explainers

Open on YouTube First HN thread

2 HN users recommended this explainer in 2 different months between 2019 and 2023.

2007–2026

2 strong recommendations 1 citation HackerTube score 3

Recommended as the clearest footage of a whip tip going supersonic, and cited in shockwave discussions.

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.

Pull quote: “I highly recommend it.” (HN, 2019)

Also tagged: whip crack shockwaves, schlieren photography, supersonic, shockwave, slow motion, physics

What Hacker News said

3 labeled comments from the HN archive; up to 20 are kept per video, favoring different commenters. Each one links back to the original thread.

Strongly recommends wolfram74 March 2019 under Nasa captures images of supersonic shockwaves

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]

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Strongly recommends nuccy December 2021 under Supersonic Trebuchet

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)

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Citations, criticism and jokes

Cites it maxbond April 2023 under Sabine Hossenfelder: I think faster than light travel is possible. Here's why

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.

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