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

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GET SMARTER SECTION

Check out Derek's video about Schlieren Photography on Veritasium!

The awesome German Paper:

University of Arizona paper:

History of Shock waves:

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April Jennifer Choi is a Mechanical Engineer and Professional Whip Artist from Peoria, IL. She has a Master's Degree in Computational Fluid Dynamics as well as several Guinness World Records in Whip Cracking. April is also a well known Fire Performer and you can check out what she does on Social Media through these links.

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Warm Regards,

Destin

Disclaimer:
“Information related to UAH contained in this video is subject to change by the appropriate officials of The University of Alabama in Huntsville without prior notice. Material and information in this video do not serve as a contract between The University of Alabama in Huntsville and any other party and do not serve as an endorsement of any paid sponsor of this video.”

[veritasium]

Destin, this is some serious hardcore science! AWESOME!

[wavydavy]

One moment in my life I was eating spaghetti and I slurped a single noodle as fast as I could and I got whipped in the face by the end of the noodle. Thanks to this data I understand now why the spaghetti noodle acted as a bull whip.

[OfentseMwaseFilms]

That ladies kids are the most disciplined kids on Earth.

[the_magic_max]

In case anyone wonders about the strange costume in the german paper at 4:11 😂

...this is traditional carneval in southern germany, to be exact in the Region around the Black Forest. One key element in this tradition, besides the costumes, is the whip cracking to scare the winter ghosts away.

Greetings from the Black Forest, Germany😉

[flymypg]

OMG! 40 years ago a girlfriend convinced me to join her in an evening class where we made our own braided leather bullwhips from scratch. We started with tanned hides, sliced them, shaved them, dressed the strips to precise tapers, oiled then braided them. It took a team of two about 20 hours to make both whips. Then we got to learn various techniques, from gently capturing things (we learned to wrap our whip around a balloon without popping it), to wrapping hard enough to break things (my favorite was sidewalk chalk, which exploded).

But the best part was learning to crack our whips. We started by simply rolling the loop of the whip down onto the floor, where it would snap when the tip smacked down. Then we gradually added more energy, a truly small amount at a time, until it started to crack in the air. Large, graceful motions that finished with a crack. Then we learned quicker moves that brought the snap a little closer in, where we learned to place it where we wanted it. I envied the folks who were ambidextrous with their whips, because my right arm was getting ready to fall off.

We wanted to see if we could capture the motion of the whip by cracking it horizontally over sand, so a few of us took our whips to the beach and tried to crack the whip horizontally within an inch of the sand. Almost impossible to do, but once in a while we did notice a puff of sand happening well before the whip had reached full extension, from a part of the whip not in contact with the sand. If only...

Fast forward 25 years, and I was on the team making a camera that could take 100, 000 frames per second (the Redlake HG-100K). When the third alpha unit became the first to work at full speed, we searched for targets that would both test the camera and thrill Marketing. Popping a balloon wasn't nearly fast enough. I thought back to my days with the bullwhip, and we immediately went out and bought a few. Despite dumping a zillion lumens into the field of view, nothing useful came of it. (Clearly, using Schlieren photography and capturing the shockwave is crucial.)

What we did wind up doing was pointing the camera at the HID bulb in an Epson video projector (torn from the ceiling of a conference room), where we captured the most amazing video of the arc wandering between the electrodes within the bulb envelope. We put a GIF of the sequence up on our website (this was before YouTube), which caused some small level of buzz online. The next morning we received phone calls from the Japanese executives of both Epson and Panasonic (the maker of the bulb). It turns out that arc wander was the primary factor limiting projector sharpness, so stabilizing the position of the arc was crucial to gaining any benefit from using higher-resolution LCDs. Two days later they were in our offices for a demo, and left an awesome pile of money behind when they departed with our very first beta unit. Their problem was that high-speed film limited the rate of innovation to one test run per day, with the film developed overnight: Our camera allowed them to do a dozen runs every day, leaping their R&D further ahead of the competition.

You may have noticed I mentioned we had to go out and buy some bullwhips. My treasured handmade bullwhip had disintegrated within a year of making it: Evidently, the tanning process used on the leather wasn't compatible with the oil we applied to it. It sure was fun while it lasted.

Now you two have got me wanting to make another one!

[Kumquat_Lord]

This is why I love the internet. You can take something as unbelievably complicated as a supersonic physics and make a compelling video simple enough for a common person to understand. Not only that, but you're showing things that are likely the world's first observations, and sharing them with the entire world

[panther-nkhn]

Honestly, I'm still just impressed that people figured out how to make the whip do that hundreds if not thousands of years ago. And only NOW do we understand exactly why it does that. So cool.

[Yeagerists]

"She's good with whips"
Me: "Continue"

[danieljensen]

>Goofs around with a high speed camera.
>Accidentally gets a PhD in whip mechanics.

[Mostly_Joe]

I've been subscribed for almost 4 years I believe and this has to be the most interesting video you've made in my opinion. Keep up the good work!

[furn]

This made me realise that Einstein would probably have a YouTube channel too explaining science and publishing new scientific papers

[davidmorgan]

I love how... iv been watching SED for years... and a question pops in to my head, and I youtube search it... and here you are! Perfection.

[nathanm.]

I can break the sound barrier with a bath towel.

[danniboi]

"Let's make a YouTube video!"
"Let's publish research!!!!"

[MikaGlitch]

I hypothesise that the knot that helps to start the force of the air breaking, leading the waves, is just enough mass change in a quick transition towards the end of that whip that is the ultimate catalyst, seeing as how the wave suddenly goes from very little mass to a sizable addition of mass, and the frayed ends are trying to catch up to the equilibriam of pressure exerted by the wave as the sound barrier is broken.

Great work on this, my science bug is wanting more. Subbed for awesome whip cracking science!

[Mister_NO.]

Just two guys having fun... i love it 😆

[Steintastatur]

best example that everyone can relate: when you slurp on noodles and when the end of one is right before your face, it smacks you

[jeanthibeaux]

Merci le gars dans les commentaires de la vidéo de dr Nozman

[jcims]

3:10 there's that look again. I see it so often in your videos...that spine tingling experience of discovery. I love it!

[Benzy]

This video was absolutely fascinating, and I feel privileged to witness this development in human understanding.
Had a moment in the video where I said, “wow, that’s a lot of doctors!”