Shockwave Shadows in Ultra Slow Motion (Bullet Schlieren) - Smarter Every Day 203

[@besmart]

I dreamt of this day, and here it is. Thank you for doing the video I hoped you would one day do, Destin. So cool 😎

[@smartereveryday]

Thanks Joe. I'm really looking forward to seeing you at ThinkerCon.

[@whothatpartycatm165]

Cool

[@cowboyup6744]

Cool

[@jimbojones1848]

very cool

[@its_me_kirankumar]

Hey i have subscribed both the channel since nearly a year

[@RealEngineering]

And normal shock is why airplane wings are angled backwards. It increases the critical mach number, the speed at which those normal shock waves begin. Really cool to see it applied to bullets!

[@sawspitfire422]

Trust Brian to bring the real engineering to the video haha

[@ivanmontano2470]

Consider me suscribed to your channel sir

[@sawspitfire422]

I had to learn basic transonic aerodynamics to play Kerbal Space Program with the Ferram Aerospace aerodynamics mod, I optimised the wing sweep for mach 4.2, which was the speed I was trying to achieve, but it took a lot of tinkering, learning, and admittedly sometimes guesswork to achieve stability through Mach 0.8-1.2. Well worth it though, just for the learning opportunity

[@TommyBoy719]

I just read that in your voice.

[@aidanforbes3532]

Therefore reducing the drag with less energy needed?

[@smartereveryday]

Thank you for watching my internets.

[@silversuckafish2138]

What an amazing video, very well demonstrated and explained. I love guns and this really taught me a lot!

[@TimothyLowYK]

Internets, my friend, is the livelihood of my eyes

[@sukhrajsingh466]

Crazy late night upload

[@uokih]

This is one of the most interesting videos I've seen on KZbin, and is one of your best. Thanks from Australia Destin.

[@cmdr2005]

Destin, I remember several articles from Popular Science/Mechanics about 10 years ago illustrating hypersonic jetliners of the future. Several of the designs had shock wave buffering waists around the fuselage, supposedly to reduce drag and noise pollution. I haven't seen that design on anything since. Know anything about that? Do you think it could be applied to long range shooting technology?

[@TierZoo]

"who uploads a slow-mo video at 3 in the morning?" Destin: "oh boy 3am!"

[@brucelankford6236]

Thanks for the info about the new balance patch, it's meta-shaking alright.

[@neuroskynet]

And yet, here we are, compelled to watch it...at 3am. Lol

[@gorgestboi1028]

Lol 6:30pm or something for me lol

[@its_me_kirankumar]

But its 1.30pm in india bro

[@Nors2Ka]

Rest of the world: huh?

[@salislazy]

What I learned from this video: Revolvers produce dramatic orchestra music when fired.

[@AmIJorge]

Sal lol

[@bjolly8924]

😂🤣🤣🤣

[@itzshayne_]

Funny how the brain works. lol

[@Gabriel-zx3ge]

Yeah but it's so fast we normally would just hear a boom

[@vinceemery5943]

I don’t know if you know this, I think you probably do, but the sounds aren’t recorded from the camera, they are just man made after the footage is recorded, they might have used a cello or something and then edited it to be a bit slower and pitched down.

[@greekpower2278]

Someone is happy that it doesn't take 11 hrs to render a video so now they're pumping them out faster :)

[@cloroxbleach5771]

So true, from 11 hrs to less than 3

[@einname9986]

I bet he has at least 10 Terabytes of slow motion footage lying around just waiting to be rendered and uploaded

[@afallingtree9114]

The fact that he gets straight to the point without all that filler (that other channels put in to get extra revenue from the 10 minuet mark) is absolutely amazing. Don’t ever think that decisions like that go unnoticed because it really shows in the quality of your content. By far one of my favourite youtubers so don’t slow down, ya almost at the big 6M.

[@Donnyf3841]

💯

[@aikonomic]

Scrolled back up to see if I had subscribed. If only I could subscribe twice...

[@afallingtree9114]

Akinlolu Oderinde ikr

[@taofledermaus]

that was awesome. Amazing that Schlieren came up with that technique in the 1800's.

[@chilling_at_pontiff]

I know right ...i swear people were smarter than they are now

[@eliack95]

Here because of you 8) Great videos, both of you!

[@Exgrmbl]

+TAOFLEDERMAUS Not to be too nitpicky, but dude's name wasn't Schlieren, but August Toepler. "Schlieren" is merely german for "streaks" or "smears".

[@MaximusPsychosis]

now i wonder if this got demonitised like you copped, because of "Harmful or dangorus act: Abuse of fire or explosives" as people tag anyone firing guns on a video do?

[@Highstranger951]

Agreed

[@logangrove4103]

3:10 Hats off to the editor for the frame by frame animation

[@thequarrymen58]

💀

[@cocobob6025]

💀

[@thirsten55]

Would've loved to see more of Dr. Konstantinos Kanistras.

[@gusbisbal9803]

To me that dude deserves his own freakin channel

[@CaffeinatedTech]

Yeah that dude looked so excited to be explaining that.

[@muhammadhayyan2665]

gus bisbal he has a channel

[@karapapaxatzidimitrakopoulos]

He is Greek

[@ArKritz84]

He's like a real life Dr. Daniel Faraday/Daniel Widmore (aka Jeremy Davies) in Lost.

[@HydraulicPressChannel]

That's some super cool slow motion footage!

[@Bibibosh]

Hydraulic Press Channel BLOW THAT DAM UP

[@scubasteve9715]

Vat da fok! Good to see you here

[@smartereveryday]

Thank you! Love your "extra content"

[@laitila87]

We must deal with it.

[@pterodox123]

@Sassy The Sasquatch wow

[@X0verXDriveX]

I got shivers when I learned that you can calculate the speed of a super sonic projectile by measuring the angle of the cone of the shockwave. Mind blown.

[@jigartalaviya2340]

Martin Rioux You can do that same thing to superman also!! Remember that teaser trailer of man of steel that played before dark knight rises.At the end of that superman flies up creating cone behind.😉😉

[@robertdurbin4252]

The fact that it is such a simple correlation blows my mind.

[@kevwang0712]

Same here too, mind blown

[@-JohnGalt-]

Prerty sure that blew my freakin' mind too...and what a perfect included angle that shockwave formed. Looked like it was drawn with a protractor.

[@ShifuCareaga]

that's what's up

[@cameronbrown7796]

*"I CAN MAKE IT I CAN MAKE IT!!!"* - The Little Bullet That Could

[@fotina45]

Actually thats the bigger one

[@JoeByron420]

I THINK I CAN I THINK I CAN

[@lazarus1867]

@@JoeByron420 lmao omg.. I had no Idea what he was saying... I thought he was pretending to speak german or something...xD

[@quahntasy]

If only our professors explain stuff as enthusiastic as Dr. Kanistras.

[@Darksaige]

Dude was happy to explain that thesis

[@bobbob123ful]

Ain't that the truth. Instead my professors make it seem as though we're the burden

[@SubjektDelta]

@@bobbob123ful school is mostly a burden because teachers get told what and how to teach it. They can't do what they want and that's not what makes you happy!

[@billpap6141]

It's because he's Greek

[@tehsma]

That guy rocks!! I want to hear him on the show more!

[@MossPalone]

If only my professor explains stuff as enthusiastic as Dr. Kanistras.

[@smartereveryday]

I regret that I didn't have an actual camera with me so you could hear him better

[@th33xitus]

@@smartereveryday Actually it is not that bad, you can understand him even without subtitles pretty good (imo) dont worry :) thank's for this interesting topic!

[@MossPalone]

@@smartereveryday Have him record a lecture with binaural recording for TheSoundTraveler. Lol

[@feirisWheel]

My physics professor in college was just like Dr. Kanistras. It made learning physics so enjoyable!

[@bruperina]

Right?! That guy knows how to make complex things sound like a piece o cake.

[@lilybailey4011]

At MIT they offer a class 6.163 called strobe photography. My group for the class did schlieren imagining as our final project and we validated the speed of various bullets using the mach angles as you've described. One other cool thing we did was observe a bullet going from supersonic to subsonic through different refraction index mediums. We created a 4 sided clear sided box with plastic wrap on the two open sides and then rigged a hair dryer to heat up the air inside the box. We positioned the camera such that we could get imaging of the bullet before, during, and after it was in the box. As you know, heating or cooling air changes it's index of refraction. We were able to heat the air in the box enough that a supersonic bullet became subsonic when it entered the box and supersonic again when it exited! The imagery was super cool, and the observation of something we expected was also a very neat experience. Thanks for making the video, I look forward to other projects you get up to with schlieren!!

[@TheMetalButcher]

So with the flash speed of around 1/1000th of a second would you get a lot of blur?

[@tiagotiagot]

Any chance you can post those videos online?

[@diao77723]

Can you post these photos / videos? I really wanna see that!

[@mark2220]

Sped back up to supersonic when it exited the box? Am I crazy or is that not possible? I guess maybe it would depend on how close to supersonic the subsonic was? New video on this, Destin!

[@NArnold48]

@@mark2220 Mach number is a ratio of the velocity of an object relative to the speed of sound in air. As temperature changes, the speed of sound changes (relative to the square root of the temperature). Combining these ideas together, if we assume a bullet is traveling at 1150ft/s, then we can look at its mach number in different air temperatures. The speed of sound at room temp (70F) is approximately 1128ft/s which would mean the ratio of bullet speed over speed of sound is 1.02. If we now assume that the bullet is traveling the same speed through a section of air heated to 120F, the speed of sound through this higher temperature air is higher (approx 1180ft/s). This gives us a mach number of 0.97. As you exaggerate the temperature difference, you will create a larger differential in a mach number.

[@ClemensAlive]

But does it have...LAMINAR FLOW?!

[@kevinshen9391]

Sure does!

[@emils4049]

I´d say it´s too fast for laminar flow... I say NUCULAR

[@fidelitypicturescom]

I think it's laminar before the shockwave and the flow separates thereafter, that's why the bullets seems to tumble around

[@emils4049]

@@fidelitypicturescom I don´t see any tumbling in the supersonic bullet. If you look more closely you see a very thing bright layer around the surface, that´s the boundary layer. The only way the boundary layer can stick around the bullet is if it has enough energy to press itself down to the surface. Only turbulent layers are that energetic. Besides, at that speed you should have turbulent flow. At transonic speeds the Airflow isn´t quite as energetic, so any imperfection on the surface of the bullet will cause a sonic boom normal to the flight path (M=1/sin(90)=1), which dramatically increases drag und forces the bullet to tumble. Even then the airflow should be turbulent, but that is measured by the Reynolds Number, not the Mach Number

[@fidelitypicturescom]

@@emils4049 thank you! I had aerodynamics a long time ago... ;)

[@akjkjkak]

You make the internet a better place. I'm bookmarking this video so I can share it with my kids when they are old enough to understand

[@matthewfredrickmfkrz1934]

Just show em or they're going to be on the video games when they're old enough to understand

[@Bl4ckw0lf1]

Him and Colin Furze. Now I'm off to see Mr. Bean's R.C. chair.

[@index7787]

I've taught 12 year olds special theory of relativity and they then told me if the clocks on satellites are set faster or slower. Kids have amazing brains, "goldfish will grow as large as the tank", keep kids in a large mental space and they will fill it.

[@RahulKumarAitian]

I have bookmarked this channel for future kids.

[@Airguardian]

As an aerospace engineer, this footage is PRICELESS! Thank you Destin! PS: Veritasium likes this, lol.

[@666Tomato666]

well, duh, the lens alone new was something like $4.9k

[@Airguardian]

@@666Tomato666 The slowmo cam puts that to shame.

[@azlidage]

Ill be honest this is the best channel I’ve ever watched. I frequently watch interesting science videos and they get me thinking but the way you explain things and the passion you have for literally every experiment you do on top of bringing in real experts that are admittedly smarter than you makes this channel top tier. Thank you for everything you do!

[@nikofloros]

Shout out to the awesome Greek professor who explains everything like you should have learned it already! Μπράβο ρε Κώστα!

[@TaRixnwOla]

If only Greeks could appreciate the level of knowledge some of our professors have. And if only professors in Greece had the same will to teach as professors abroad. Greek or not.

[@nikosrap]

@@TaRixnwOla τα καλυτερα μυαλα παγκοσμιως ειναι ελληνες θα τους βρεις στα μεγαλυτερα πανεπιστημια, στον κοσμο της NASA και σε πολλους αλλους τομεις απλα η ελλαδα σκοτωνει κυριολεκτικα αυτα τα μυαλα με οποιονδηποτε τροπο γι αυτο και διαπρεπουν και ξεχωριζουν κυριως στο εξωτερικο οπου υπαρχει η αναλογη αξιοκρατια

[@TaRixnwOla]

@@nikosrap Δε θα μπορούσα να συμφωνήσω παραπάνω. Προσωπικά πιστεύω όμως πως το φταίξιμο είναι 50/50 για το επίπεδο στα ελληνικά πανεπιστήμια. Από τη μια καθηγητής γίνεται οποίος έχει βύσμα και τα γνωστά. Και αν μπει κάποιος που δε τα γουστάρει αυτά δε θα ανέβει ιεραρχικά ποτέ. Δεν υπάρχει έλεγχος οπότε ο καθένας κάνει ότι θέλει. Διδάσκει ότι θέλει, όπως θέλει και αξιολογεί όπως θέλει. Από την άλλη είναι ο Έλληνας φοιτητής που γουστάρει δε γουστάρει η ελληνική οικογένεια του ζάλισε τα αρχίδια να μπει σε μια σχολή που ίσως και να μη του αρέσει. Δε δείχνει κανένα ενδιαφέρον και τα λοιπά. Με λίγα λόγια ένας καθηγητής στην Ελλάδα ακόμα και όρεξη να έχει να κάνει κάτι καλό, με τα χρόνια βλέπει πως λειτουργεί η φάση και γίνεται σαν τους άλλους.

[@MlTGLIED]

@Vasilis Angelakis I agree, it's not only problem in greece. Greetings from Germany

[@TaRixnwOla]

@@MlTGLIED I know. I just finished my masters in Denmark. The phenomenon is way more frequent the souther you go. It all comes down to characters eventually. Have a great day :-)

[@MarvinBowen]

This video is A+++++. This channel is easily the best thing on the internet. Entertaining. Enlightening. Not judgmental. Educating. Upbeat. Mind opening. Thank you, Destin. Thank you.

[@Mythricia1988]

Man, that explanation for why the subsonic bullet had those shockwaves was so logical, it almost hurt a little bit that I didn't see it coming. Of course, it's basically a wing shape, the air has to accelerate to make it around, and goes supersonic while doing it. So simple.

[@bigbuckoramma]

You should look into Compressibility and Critical Mach. This was a big problem in aircraft design towards the end of WWII, and coming into the jet age. One of the really cool things, where you can see engineering and science at work, is that NACA in the US, a small group of British engineers, and a hand full of German engineers, all realised this critical mach problem mid war. And quickly began looking at ways to reduce the drag caused by the shockwaves, as well as the control surface issues from Mach Tuck. All of these programs we're considered above Top Secret, yet post war they discovered that all of them had, more or less, hit on the identical wing shape to reduce the shockwave size and drag effect. It's worth the deep dive, there is a TON of good science there.

[@camman641]

Yeah even as someone who knew about the transonic range and that this does occur. that's why planes either fly significantly under speed of sound or significantly over it, this explanation made my understanding so much more clear.

[@KillaCowboy]

I'm guessing that's a shrinked down image of how a fighter jet looks when it's about to break the speed of sound

[@bigbuckoramma]

@@KillaCowboy Correct. If you see video footage of say, the Blue Angles, making a transonic pass at low altitude, you will see multiple shock wave fronts forming around the surface of the aircraft. There is also an image of a JSF going transonic and there are little tiny shock cones forming under the aircraft. Looks really cool.

[@Mythricia1988]

@@bigbuckoramma I vaguely know about compressibility and related things from flight sims, it's quite interesting. I remember reading about it in the official pilots manual for a P-51 Mustang as well, they somewhat tackle Mach effects in the manual due to the Mustang having a very laminar flow design wing, and was easily capable of reaching the (dangerous) trans-sonic region in dives from high altitude. If I recall correctly NACA came up with basically a formulaic way of defining wing shapes (NACA airfoils?), that has been in used ever since; all as part of this related research.

[@alden1132]

I noticed an interesting feature of the turbulence DIRECTLY behind the bullet, the "line" drawn by the path of the bullet. If you look carefully, the turbulence is spiral shaped, due to the rifling-induced rotation of the bullet around it's longetudinal axis. The tailing turbulence is actually *twisting* with the bullet. The twisting is what governs the shape of the turbulence is it dissipates, as well.

[@BiggMo]

Destin...So.... can you recreate your (gun) suppressor video using these sound photo techniques? Would love to see how suppressors manipulate sound waves.

[@Sigo_NA]

SO MUCH YES. PLEEEAASE DESTIN!

[@J.Wrecks]

What about barrel oscillations and why people free float them... that would be so cool to see a barrel flex in slowmo.

[@willemkuperus4988]

Great idea! Yes, please Destin!

[@69CamaroSS]

YAAAASSSS!!!!!!

[@rigille]

He did it :)

[@PerMortensen]

Oh, and Dr. Kanistras was great. I'd love to see more of him.

[@IgorDz]

Now sell the footage to any new James Bond movie as an opening.

[@osamabinladen824]

Cool idea!

[@guloguloguy]

.....YES!!!!!!!!!.......

[@RIPToot]

Lol. What? Why?

[@luiza3289]

Veritasium: "Let me clap my hands so maybe I can have a good amount of shockwave shadows comin' out" SmarterEveryDay: "So, here we have a 300 blackout supersonic" Love you both :)

[@barakathiongo4835]

Destin is just to cool

[@MrScottyMillz]

I wonder what would happen if you shot through a vacuum chamber, like actually shot the vacuum chamber, how quickly you would see air enter behind the bullet..

[@mattheoswho1010]

What an amazing idea!

[@atheistonavmax7873]

Or fired the revovler inside a vaccum chamber at full vaccum. No air resistance to the shockwave as well as the pressure wave reversal as it peirces the side then implodes back inward from high pressure to low pressure. Even without atmospheric oxygen i believe the shell would still fire. #Codyslab

[@MrScottyMillz]

@@atheistonavmax7873 That would be really good! Im not even sure if it would fire without air.. Also a firing mechanism would have to be build inside the chamber with a remote trigger pull. Not sure how a string would work being it would have to lead out of the chamber to be pulled manually.. Im sure Destin can think of something

[@MikeWallaceTWB]

Bullets will fire without air, there are plenty of videos of them firing under water. A RF controller and a servo inside the vacuum chamber would work just fine.

[@jonathankydd1816]

@@MrScottyMillz gunpowder is self oxidising, it doesn't need an external source of oxygen (such as air) to fire.

[@ghhg-je8wv]

I had a dream you would do a Schlieren bullet video... how awesome.

[@TheDarkMessiah]

Ah, yes. 3 am. Optimal video upload time.

[@magnuspeacock5857]

7AM here

[@dharmeshsolanki4354]

1 pm in India

[@awiseseal7559]

6:30pm here

[@gentlejake605]

3 for me XD

[@Mirorval]

I am from Russia and its good time.

[@KathrynLiz1]

As a life time shooter (I'm 76 now) and also with an aviation/aerodynamics background this was very interesting......especially the localised supersonic airflow on a subsonic projectile.... Great stuff and wonderful filming...

[@FarrelClement]

That's why you lose so much accuracy once a round goes sub-sonic. There's so much turbulent flow in the transonic region, it's difficult to get consistent behavior out of a loading.

[@tomharrell1954]

Did you know the same thing happens with a helicopter’s roter blade. The blade meeting the wind in the direction of flight meets air at the speed of the chopper plus the speed of the rotation of the blade. The combined speeds go supersonic on the edge of the blade producing the noise of the blades. This is what limits the copters ability

[@jason127x99]

Thomas D Harrell interesting!

[@DJKillahKoba]

2:18 I like that you can clearly see striations in the 'wake' turbulence caused by the spin of the bullet.

[@MrDelPreston]

You should try this revolver thingy with the Nagant M1895. It has a special system that will move the cylinder to the barrel once you pull the trigger. You might see less or no gas coming out the gap.

[@stormagheddondarklordofall7171]

This is why the Nagant can have a suppressor where other revolvers cant due to that gas seal. Super cool gun.

[@adamkendall997]

Awe man I was totally thinking of something just like that. Oh well.

[@wobblysauce]

+

[@F3Ibane]

And just like that, Destin starts asking all his buddies to loan him an M1985. It's Alabama, so somebody definitely has one.

[@Varadiio]

Pulling the trigger on a Nagant cams the cylinder closer to the barrel, but the ammo is also purpose-built for this. Unlike normal revolver ammo, these stick out beyond the cylinder, and the case extends beyond the bullet. The case seals the gap between the cylinder and barrel when fired.

[@DanielRenardAnimation]

Now go ask the U.S. Navy nicely, if they'll pop one or two of those $25,000 7 x SuperSonic rail cannon shells in the name of science! 😛

[@emptyforrest]

if those rounds costs 25 grand they are really getting ripped off. as its an inert kinetic round. or maybe you just got it wrong and the cost of firing is 25grand, as it takes quite a bit of energy to do so.

[@DanielRenardAnimation]

@@emptyforrest *Julius Levinson:* _"You don't actually think they spend $20,000 on a hammer, $30,000 on a toilet seat, do you?"_ ― Independence Day (1996) hashtag-LOL-U.S.-Military-Spendings

[@sgtzack612]

emptyforrest it’s because the material it’s made of and the way the shell is makes it cost so much

[@yurtttttt96]

sgtzack612 yah nah. It’s a magnetic projectile. There’s only a few natural ferrous elements & they’re extremely common in the earths crust.

[@atheistonavmax7873]

I remember the first time I peeked through a microscope in awe of what was too small to see with the naked eye! This is the same feeling here seeing something that is too fast to see let alone seeing a force usually only felt due to its precieved invisibility. This is a truly beautiful thing of mechanics and even fluid dynamics as the subsonic bullet acts like a wedge splitting, ramping, diverting, and accellerating the air around and away from it to supersonic . . . .

[@adityananda3166]

When the camera pans down when he says "I got this giant 16 inch......"

[@hadroncollider1155]

Lol

[@Jakeguardia]

You dirty girl.. ;)

[@fuckednegativemind]

@@iknowyouknowiknow7389 To have a good laugh?

[@jamesporter1991]

Man, the supersonic fins on the sub sonic bullet totally dumbfounded me until it was explained. Then it made so much sense it was like "duh, of course that is whats happening".

[@DWSOutdoors]

Its still a MIND EFF.... lol Go to store to buy sub sonic ammo for silenced gun... find out it still breaks the sound barrier because of the shape and the air speed around it lol

[@DehimVerveen]

It's Bernoulli's principle, right?

[@galesx95]

@@DWSOutdoors haha do you think someone would sue the bullet companies? XD

[@DWSOutdoors]

galesx95 not sure if they would let you demonstrate that one in court🤔

[@pulivikas7199]

Felt the Same here mate 👍😂😂

[@mountainhobo]

Brilliant. Curious what a shockwave from a multi-projectile round like a 00 Buckshot would look like.

[@nick4819]

Ooooo can you do a whip cracking with this?

[@Joseph_Hartmann]

@@Yora21 Someone needs to ring up Anthony De Longis, he seems to like making appearances in things like this, and he's a modern master of the bullwhip.

[@pavelk.2176]

I think backyard scientist did that :)

[@nick4819]

@Paci Paci Pac ahhhh you are correct. He referenced this video here: kzbin.info/www/bejne/opPSnqaFhbiGf6s

[@stockbulll]

The science behind this is literally giving me goosebumps! I could watch these types of videos forever!!!! Please keep slow mo ballistics coming!

[@airos52]

You're the first KZbinr I've allowed bell notifications... I have never seen a video I didn't enjoy. I haven't been watching your channel for more than a couple years but I really enjoy your content. Thank you!

[@juanvaldez3352]

Wow! Very cool! This is the same phenomenon that causes Bremsstrahlung radiation! Charged particles moving faster than light in a specific medium (say water or ice) is equivalent to an object moving faster than sound in air! In neutrino detectors (like IceCube), we measure the "Mach angle" of the light cone produced from the radiation and that tells us the speed (energy) of the incident neutrino! Amazing! Source: Astrophysicist

[@Scott_C]

Yes! It's amazing how there are a lot of theories that correlate between speed of light and speed of sound.

[@ArosaOnline]

I went through three years of an aviation engineering degree and failed to notice that Mach and the angle of shock waves have such a simple correlation. We always calculated Mach from the local speed of sound and the speed of the object. Beautiful!

[@RandomNumber141]

surfingbishop The method you’ve learned for calculating Mach number is the most useful in terms of aviation. Hard to set up a schlieren system on the wing lol

[@ajdarmar]

surfingbishop Its not that simple. You have to solve (or see the graph) of theta-beta-M equation to find the Mach Number ,and its only valid in 2D flow. This is obviously a 3D case.

[@RandomNumber141]

Daryoosh Kazemi Ah yes, can’t forget the three dimensional relieving effects!

[@absolute9951]

0:12 which is why I’m pretty excited about this giant 16 inch (looks down) 😆

[@djjazzyjeff1232]

That caught me off guard too! lol I was like NO NO NO NO, oh, right... 😅

[@namelessguy199]

0:12 which is why i am pretty excited about this giant 16 inch p-

[@bluesky6905]

This might be the funniest comment

[@bloviatingbeluga8553]

Totally went over my head hahaha

[@ojtheaviator1795]

-arabolic mirror! What else could it possibly be? /s

[@tomfischer1139]

What you should do with this is you should Film this 10 times, moving the camera foreword every time and put it together, so that you can see the flight of the bullet over a few meters. That would be so awesome!! Like a bullet flight panoramic video.

[@_SKDK_]

Before he did the breakdown of the subsonic bullet I kinda felt like I knew what it was already. The lines around the bullet reminded me of a jet as it's accelerating and beginning to pass the speed of sounds. There's a brief period where you see a "cloud" surround the jet and it looks alot like that bullet.

[@EBinCA]

At first I was thinking it was a disruption in airflow due to a cannelure around the bullet at the point of the disruption was about where a cannelure would be on a rifle bullet. My thought was this indentation would be causing the smooth air wrapping around the pointed end and flowing around the sides to ripple a bit as it flows over the cannelure in the bullet jacket.... but I guess I was wrong :-)

[@michaels.1676]

@@EBinCAr/iamverysmart

[@rodneysabuero]

The smoke in a jet is not the Sound wave, you cannot see sound wave or sonic boom in a naked eye. The Cloud in the jets are cause by cold relative air that surrounds the jet/bullet, passes to the rear side of the jet/bullet which is a very hot area, changing the Temperatures from extreme cold to extreme heat at a very Fast Rate could cause a cloud that can be seen in the pictures of Jets reaching Mach 1 above.

[@suokkos]

In some pictures you can see water to condense behind shock waves.The effect is calle Vapor cone. The effect is caused by temperature reduction around the jet/bullet and high relative humidity (highly simplified explanation of thermodynamic process happening). There is pressure raise and drop which have matching temperature changes.

[@Cantreachthestars]

8:45 *Sound starts* Hanz Zimmer: *starts drooling*

[@highoctain113]

That was absolutely educational... The fact that the subsonic bullet still has supersonic events. Amazing.

[@MideanStone]

Yep agreed this tickled my brain in all the right places haha.

[@bcikablam3578]

you undoubtedly discover and post some of the most amazing things on earth (and beyond)! we can't thank you enough for taking the time to share these experiences with the world!

[@Christoph1990]

I would never have thought that calculating the Mach number would be as easy as 1/sin 𝛗. Mind blown 🤯

[@Yora21]

It probably was picked as a unit of measurement because it's quick and easy to calculate.

[@Christoph1990]

@@Yora21 What do you mean? The Mach number simply is the factor of the speed of sound of an object in a particular medium. It just amazes me, that there is such a simple geometrical solution of calculating it.

[@paulleimer1218]

Well technically it is trigonometric

[@Christoph1990]

@@paulleimer1218 trigonometry is a part of geometry...

[@paulleimer1218]

@@Christoph1990 fair enough

[@jobfaber3624]

I love to see the enthusiasm of the professor so much, he makes me want to go learn more about aerodynamics

[@declanditchfield4205]

Haven't watched it but I already like it. Edit: After watching it's still good

[@thooke222]

That's pretty awesome that you can calculate the velocity based on the angle... Never knew that

[@iicordii648]

You learn that in high school lol

[@dharmeshsolanki4354]

we get another video ..... looks like new computer is working great... video editing getting faster everyday 😂

[@weaponizer4444]

i would love to see what effect whip crack will make

[@javafloof]

W.M. return they made one

[@AutoRoundz]

So look it up

[@williammitchell1864]

W.M. return, Probably about the same effect or similar to the bullet.

[@RitaMaru11]

They did actually make one

[@justsayin7704]

The whip was done decades ago. Where have you been?!

[@jhendren0001]

That was definitely my favorite video to date that you have made..thank you for your hard work, yes I know it's fun and you love it but I understand it is still very hard work and I say thank you.

[@GokantheHusky]

Destin: This is a Phantom V-2511. *The Slow Mo Guys want to know your location*

[@cascastenmiller9152]

I have been watching your video's for a long time now, and never really wondered what the psalm you refer to at the end of your video's sais. I looked it up today, and I think it is such a perfect way to discribe your video's. Thanks for all the work you do, and keep it up!

[@FRN2013]

"Great are the works of the Lord; they are pondered by all who delight in them."

[@dt5101961Nelon]

Watching the shockwave pattern of a revolver fire. The hand barely stays in the safe zone. The first person who invented revolver must be nuts!

[@bionicleone]

Squiggummer Figgammus it can seriously damage or sever a finger so I’d say it’s as bad as it looks.

[@Cubinator73]

I guess that those faint circles coming off of the bullet in regular intervals are due to the rotation of the bullet and some imperfections on the bullet. Just a guess though.

[@thefunkosaurus]

I'm almost positive that the observable circles are due to the shape of the bullet. If it had a square section, I believe that shape would be propagated.

[@bbgun061]

Cubinator73, perhaps they are coming off the rifling marks that the barrel forms in the bullet?

[@nunyabizness6734]

they are the troughs and peaks of the pressure waves

[@runamucker]

Could be determined if it's rifling by doing it with an otherwise identical gun, and comparing the exact distances between the lines. If it is the rifling, and if we're really lucky, the lines might somehow directly compare with the striations on the actual bullet.

[@ownthore]

@@nunyabizness6734 exactly, the preasure builds up then releases in regular pulses based on the speed of sound, shape of round, and speed of bullet. It compresses the air to a limit then the compressed air "explodes".

[@prepperpov5852]

*YES, SIR! THANK YOU FOR ANOTHER GUN VIDEO! I HAVE A REQUEST FOR A FUTURE GUN-RELATED VIDEO... TANNERITE! PLEASE FILM A TANNERITE EXPLOSION (bullet impacting the tannerite) IN SLOW-MOTION! I wish you the best as far as KZbin’s censorship, too!*

[@smartereveryday]

You still have your earplugs in and you're yelling again.

[@prepperpov5852]

SmarterEveryDay *in whispering voice* Well, I do make ASMR videos about guns, so pardon my excitement but I will admit that it’s out of my norm to be so loud... very sorry. Also, I’m at work right now and literally do have earplugs in so you are not wrong at all

[@asmhsn6968]

0:12 Pretty excited about this GIANT ... video stops for buffering at the very wrong time :D

[@wildhund78]

Lol

[@mmeovv]

deserver more like

[@adilmhaisker6477]

And he moves the camera "down"... :P

[@daveb1870]

The circles are the boundary layer coming off the back of the bullet, they exhibit a circular shape because of the spin of the bullet. You can see it better with the subs as. It also proves that even though airs mass is so minute the physics behind it are amazing as the boundary layer both keeps it on the bullet and keeps it from coming off the bullet.

[@Benzy670]

I absolutely love this. The Schlieren Effect is one of those scientific discoveries that might as well be magic. So simple yet so effective, too! Thanks for teaching me some stuff today, Destin and Dr. Kanistras!

[@pavelk.2176]

Most underrated channel on youtube.. My brain is literaly MELTING this is so awesomely awesome. THANK YOU DESTIN.

[@pirateman1966]

You're literally exaggerating.

[@pavelk.2176]

@@pirateman1966 or am i??? *vsauce music plays*

[@ketsuekikumori9145]

One of the coolest moments of my life was seeing a shockwave coming from a traveling bullet. I was shooting at the range with my dad. I was spotting for him and could see the bullet travel downrange with a shockwave following close behind. I think the reason I could see it happen was the weather was perfect for allowing me to see it with the naked eye. I'm curious if any meteorologist could go into detail on how the shockwave was possible to see. I don't remember much other than it was raining that day, a light drizzle I believe, and maybe had high humidity since it took place in Florida and most rain happen because of high humidity. Wondering if air pressure played a factor.

[@Scott_C]

Vapor pressure. Compressed air is more dense. More dense air holds less moisture. The bullet was literally squeezing the water out of the air. The reverse action happens when you breathe on a cold day. Warm moist air in your lungs is visible.

[@PistolasFritas]

Ketsueki Kumori it’s an awesome experience. I was not just able to see it too, i was able to recorded. The sun was behind the camera at 45 degrees. It was cold 44 degrees. I was able to capture it without mirrors, live, the shockwave of a revolver. Unreal. I am just editing the video so you can see it. Regards

[@jimthegentleman2446]

Dr. Kanistras has such a greek accent that even if I didn't know his origin i would know he is greek🇬🇷🇬🇷

[@anders5611]

For some reason it's very similar to a spanish accent.

[@executivesecretary1648]

We had a wind tunnel at College that would do supersonic speeds... using schlieren. The tests were just like this only the bullet was stationary and the air was moving by it ... The throat was only like 4x6 inches, and had windows on both side We had a light on the far side and we would tape paper on the near side and trace the shock angles by hand. We tried taking pictures of it (film) but most of time they didn't turn out. We had this huge tank of compressed air - it would run the wind tunnel for about 4-6-8 seconds depending on the Mach number. The University didn't want us to do to many tests because it would cost to much money for the department and they had a limited budget. Then we would have to wait like an hour for the tank to refilled before would could do the next test. This was in the mid 1980's at the University of Utah. Brings back great memories.

[@thomasbunce4342]

Very similar set up at Purdue. I only got to use the supersonic tunnel once, but I didn't take the advanced labs or go to grad school.

[@michaelmatthews6772]

At UAH, Dr. Ligrani oversees research at the propulsion research center at UAH that uses a supersonic wind tunnel. I've never used it unfortunately lol.

[@patrickbolt3914]

Dustin, you have one of the best KZbin channels of all time! Extremely thought provoking and then your ability to break it down is stellar. Thanks.

[@patrickbolt3914]

Sorry I spelled your name incorrectly.

[@bastscho]

5:15 is the funniest thing ever! :D

[@saruwatarisa]

I kinda wanna see an edited video of the bullet and the voice over of the guy saying "I can make it" Lol xD

[@noonedude101]

As an airline pilot, we determine our maximum speed by our Critical Mach number. That number is the speed at which you begin to see localized areas of supersonic airflow. On my current equipment, we can fly at a speed of m.82. At m.83 (theoretically; there is probably a margin of error built in) we begin to see supersonic airflow in localized areas such as antennas, control surfances, etc. This can cause severe buffeting or even mach tuck if the shockwave builds and reaches the right point on the airfoil. Fantastic video. I've repeatedly been shown this type of imagery for both subsonic and supersonic airfoils, but NEVER a transonic airfoil. Behind those little whisps are where a wing would begin buffeting due to the shockwave disrupting laminar flow over the surface. Absolutely fantastic!

[@autizmo655]

...and sometimes we get *angiry* at other people - Destin (SmarterEveryDay), 2018 -------------------------------------------------- Another Book I would recommend that I would say is even better is "The Righteous Mind" by Jonathan Haidt. It's a book that goes much deeper than the other one on the reasons why we behave like we do rather than just trying to deal with it. I highly recommend it to literally anyone since it goes deeper as mentioned to try to explain the things behind the scenes so one can actually understand the outcomes we have, and then take our "Nature" to bring forth the out come one might desire instead. So as not the play into the olden idiom of "Ignore your shadow and it will come back on all four". And just the science and research behind it all is fascinating.

[@electro_fisher]

Not to mention Ben Sasse has a vested interest in keeping people disinterested in politics... The book you mentioned does seem to take a more analytical view of tribalism though, seems interesting

[@NeoAcario]

Having a history in both the Army and Engineering in college.. I expected every part of this video - Save 1 thing. It never even occurred to me that there would be supersonic particulates coming from the muzzle of the AR-15/.300BLK. That was a genuine pleasant surprise. I would actually be curious to know precisely what those were. I'm more inclined to assume they were dislodged bits of fouling from previous rounds inside the rifling grooves than un/exploded grains from the stick gunpowder used in rifle cartridges. Easy way to tell which one of us is right - thoroughly clean the rifle barrel.. and test again!

[@ravissary79]

its quite common to have unburnt powder leave the barrel of a gun. It's partly how CSI people investigate who shot a gun, there's unburnt "powder" particles on them. SOme of this is more or less common depending on the recipe you're using vs what primer vs barrel length. Having grains that are unburnt after leaving is not unusual, but like it said, it can be minimized quite a bit. But he was shooting an SBR, so the effect is going to be increased, even with a 300 blk. He said those supers were about 1500 fps, its very possible he was using a sub optimal recipe and was handloading. 1500 isn't typical for the good supersonic hunting loads, especially if the bullets are about 120 gr or so, and not 150s (he said the subsonic was about 100 grains heavier, but 250 gr subs for 300 blk are almost unheard of).

[@abrahamcastillo8500]

that is sooooo COOOL. you guys should see what those shock waves look like with those see through suppressors you did a while back.

[@RICDirector]

You know...usually, when I re-watch videos, I'm playing solitaire over in a corner of the screen and not really paying attention .. Destin, you're a pain. I can't go away from your dang videos long enough to catch up on my solitaire!! It's addictive, I can't shut you down. LOVE YOU!

[@alexjackson2771]

So...I've been watching this more than I'd care to admit and I can't help but wonder what sabots would look like coming out of this. Like the Remington accelerator ones, .224 out of a .30, that kind of thing For anyone who doesn't know, the sabot is a plastic cup that goes around a projectile so you can shoot a wider barrel to shoot a smaller projectile at a ridiculous velocity before it splits away from the bullet in flight Just leaving this here in case you decide that might be interesting enough to film

[@AnonymousFreakYT]

"Normal flow" - AKA supersonic airflow over a subsonic projectile - I learned that in my Aerospace Engineering courses 20 years ago. That's one of the main reasons commercial airliners travel at about 0.8 Mach, rather than much closer to Mach 1 - even at 0.85 Mach, a 747 has portions of the fuselage/wings/tail that have supersonic airflow. And airflow right at supersonic speeds has a *LOT* of drag. So the preferred cruising speed is the maximum speed where there is minimal supersonic flow. That's why average airliner speeds have actually gone *DOWN* since the 747. To minimize this supersonic flow. A 747 *CAN* achieve speeds of 0.95 Mach, but it becomes *VERY* inefficient at those speeds. That 10% Mach increase in speed can decrease range by 20%.

[@tiagotiagot]

What happens if a 747 is at those maximum speeds and then goes into a dive without the throttle nor anything being changed to slow it down? Does it go fully supersonic? Can it survive that?

[@thomasrosebrough9062]

Anybody else have a moment of confusion when he pans down at the beginning and the bottom half of his body just appears to be a tiny top half?

[@RyanRussell885]

So cool to visualize compressibility on the subsonic round! It’s incredible to think that some 80 years ago or so, the effects of compressibility weren’t full understood, and many pioneer aviators were killed in accidents related to the phenomenon. Now we can make videos of it in our garages at home, and post it online for millions to see. Ok maybe some of us ought not to (ie: if you live in a townhouse 😂), but you get my drift.

[@Teraplexor1]

Love SmarterEveryDay, always so interesting! Never hate an episode

[@ErichEats]

It's funny how you steer away from politics, but so eloquently talk about what is wrong with the era of politics we live in. Hats off to you sir. :)

[@Amigps01]

Erich Schmidt ......he got it from the book lol You should read it!!

[@PR4NV]

Did you notice that the MacBook that plays slomo video in this video, runs on Windows 10???

[@ClayCGaming]

good one mate lol and for those searching for it, it's 1:31

[@mithun199]

Also at 9:04

[@skepticmoderate5790]

So what?

[@mrwoodcat]

thats illegal

[@AquaConGas]

bootcamp

[@stewiegriffin289]

Best part(Quote)If your not into this I don’t know what’s wrong with you!...I have always wondered how much power was lost in a revolver due to the open cylinder.Really cool video.

[@ExodusAttacKGR]

awsome :D and Greek Guy on the white board i think? :))) greetings from Greece dude

[@ntain]

Μονο απο την προφορα καταλαβενεις αν ειναι Έλληνας η οχι...LOL haha😂

[@ExodusAttacKGR]

@@ntain yup xD

[@Max_Marz]

man that revolver clip is just absolutely friggin ridiculous

[@ArchangelExile]

I like how the guy kept firing before the word "fire" is even finished being said.

[@timaddams1880]

so gotta say this i been shooting for 47 years and have alot of experience with firearms and ammo as well as reloading...so i most likely been shooting longer than you been alive...and with that i wanna say this "every man is my equal (speaking of you here) in that i may learn from him ...that phrase says it all i certainly learned something here today and i cant thank you enough for the education i got from this fantastic video...and special thanks to the Doctor for his input too.....thank you so much it fun to watch...

[@bryanmaynez4117]

You look really happy and it seams you make friends everywhere you go. I wish you the best

[@andor3xy712]

This is one of the best videos I have seen. I'm so used to seeing 2d waves of soundwaves but its so hard to get good 3d visualizations of sound. The choise of soundsource was great, but man please, you should do instruments, the shockwaves of guns are really noisy, but intruments and synthezisers must have this beautifully ordered waves at regular frequencies. please please do this

[@cliffkelley963]

The slow-mo video of the revolver also shows the hilarity of putting suppressors on revolvers!

[@Ashcrash82]

I can't believe I just now found this video. Combining science with one of my favorite things...firearms. Hands down, no contest, best video I've seen on this channel. And that is saying something, because most of my favorite KZbin videos are from this channel.

[@PrimeGaming10]

That professor had a super-sonic waves on his forehead itself !😎

[@Mrgunsngear]

great info as always

[@bulko89]

Please film your Tesla coil sparks in this way.

[@mg42sd]

You know an expert is REALLY good when he talks about complicated stuff like it's some small talk at the pub.

[@animalmother556x45]

...........idea for future video. Find a machinist with a lathe that would be willing to make you some bullets (solid copper would be the easiest, don't use steel as it will not be kind to the barrel of the gun). Preferably a rifle round. Pull a bullet out of a casing of whatever caliber you choose so the machinist can duplicate it precisely...but instead of the relatively blunt rear, have him taper it to a point to see how much of that irregular "drag" shown in this video can be eliminated.

[@soranuareane]

@SmarterEveryDay You want to do this. Perhaps hook up with TAUFLEDERMAUS for some of his amazing insight.

[@unambitious]

@animalmother556x45 That's how 6.5 grendel works. It has a very good ballistic coefficient because of it's tapered tail end. In fact, it has a better ballistic coefficient than .308 and carries it's energy farther.

[@animalmother556x45]

@@unambitious I've never seen a 6.5 projectile with a tapered rear...do you have a link?

[@animalmother556x45]

@Grimace427 Yeah, I've never seen a bullet that actually comes to a point on the back. It has probably been tried before...I just wanna see it with this high speed camera setup

[@unambitious]

Boat tail, yes. It's tapered, but not to a point like the business end. @Grimace427 6.5 grendel does carry it's initial energy farther than .308. Not as much energy as .308 obviously, but it's as accurate with less drop than .308 and similar ft/lbs as 7.62x39. Plenty of "poor man's" 1000yrd setups and demos of 6.5 grendel on YT.

[@Sonicexpres]

"do you know what the speed of sound is?" "its like twelve something"

[@Taz-X]

I was dead lmao that made no sense

[@kengamble8595]

It depends on the altitude !

[@evanemanuel1774]

@@Taz-X let me make sense of his expertise for you. He claimed the subsonic bullet traveled at "a thousand-eighty" 1080 fps and that the supersonic bullet traveled at "fifteen hundred" 1500 fps so by his verbiage, "around 12 something" should easily translate to the 1200 fps which is, as I'd say, close a-fucking-nough to the 1125.33 fps speed of sound of air at STP.

[@FarrelClement]

@@Taz-X 12-something, as in ~1200fps.

[@Sonicexpres]

@@evanemanuel1774 didnt need an explanation... i understood it... it just sounds funny.

[@-dash.]

Veritasium have a great video on how the camera and mirror is set-up to capture Schlieren images

[@PYRAMIDHEAD1051]

Shock waves associated with turbulence in the wake of the bullet and expanding gasses are spectacular to watch. Optic methods such as Schliren's photography,Mach-Zehnder interferometer were once confined to Fluid dynamic textbooks,thanks SmarterEveryDay to bring this into public domain.