3 Ways Of Seeing Invisible Air Flow

In this lab, they use different flow visualization techniques to help detect contraband, residues, and develop trace particle detection methods. Part of this video was sponsored by Caseta by Lutron. Find out more at casetawireless.com/veritasium
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Thanks to Rich Press and NIST for the great visit.
Thanks to Matt Staymates for taking us around his lab and showing us the fascinating research being done with flow visualization.
You can check out all the cool work going on at NIST here: www.nist.gov/
▀▀▀
Check out these Lutron products:
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www.homedepot.com/p/Lutron-Ca... -White-P-PKG1P-WH-R/206792507
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References:
Staymates, M.E., (2020). My Stay-at-Home Lab Shows How Face Coverings Can Slow the Spread of Disease. NIST. - ve42.co/FaceMaskNIST
Staymates, M. E., et al. (2016). Biomimetic sniffing improves the detection performance of a 3D printed nose of a dog and a commercial trace vapor detector. Scientific reports, 6(1), 1-10. - ve42.co/Staymates2016
NIST. (2022). Surface and Trace Chemical Analysis Group. - ve42.co/NISTgroup
▀▀▀
Special thanks to our Patreon supporters:
Bernard McGee, James Sanger, Elliot Miller, Brian Busbee, Jerome Barakos M.D., Amadeo Bee, TTST, Balkrishna Heroor, Chris LaClair, John H. Austin Jr., OnlineBookClub.org, Eric Sexton, John Kiehl, Diffbot, Gnare, Dave Kircher, Burt Humburg, Blake Byers, Evgeny Skvortsov, Meekay, Bill Linder, Paul Peijzel, Josh Hibschman, Mac Malkawi, Mike Schneider, John Bauer, Jim Buckmaster, Juan Benet, Sunil Nagaraj, Richard Sundvall, Lee Redden, Stephen Wilcox, Marinus Kuivenhoven, Michael Krugman, Cy 'kkm' K'Nelson, Sam Lutfi
▀▀▀
Written by Derek Muller and Emily Zhang
Edited by Trenton Oliver
Animation by Ivy Tello
Filmed by Derek Muller, Raquel Nuno, Trenton Oliver, and Emily Zhang
Additional video/photos supplied by Pond5 & Getty Images
Music from Epidemic Sound
Thumbnail by Ignat Berbeci
Produced by Derek Muller, Petr Lebedev, and Emily Zhang

[@scwewywabbit]

This is the first time I've seen Derek is completely quiet almost throughout the entire video and not having to ask many questions or prompt the speaker and explain it to the viewers because Oh My God! The way Matt explains this is almost like listening to a cinematic story teller taking you though some of the most mind blowing scenarios and you are actually visualizing in your head the vivid details he's explaining! He's like the OG CSI!

[@techsoul5590]

Yeah, he's a salesman for evil, he has to be good at his job.

[@sawyer3818]

@@techsoul5590 most people have to be good at their jobs, regardless of whether you think its for evil or goof

[@willk113]

Guy was really not that smart or good at speaking i dont get why everyones jerking it to him

[@techsoul5590]

@@sawyer3818 Incompetence is far more common than you give credit for. Sales/PR isn't the place for incompetence or morals though.

[@riparianlife97701]

A TV producer would be mad at him for wasting 6 seasons of crime science on a KZbin video.

[@olimpiacookiethrower]

This guy was amazing, he explains things so damn well and there's no need for a question

[@veramae4098]

They exhale out of the small "crescents" on the sides of their nose. A different route from inhaling. Horses do the same thing.

[@godspeed2145]

There are smart people, & then there's this guy

[@GregMoress]

He's a good boy! Such a good boy!!!!

[@JaiPritchett]

You would need to say that the people he interviews are very good at explaining things to him and he is just really good at relaying that information

[@expioreris]

A question: do we really need that turbulent outflow that goes out through the same holes but slightly tilted backwards?

[@murphynuglene3714]

You can tell this guy absolutely loves what he does. It's so awesome.

[@gutika113]

Yeah, but the application of his work is straight for use by law enforcement 👎 🥾

[@coolcatawesomesauce]

@@gutika113 so its bad to solve crimes?

[@StratixGaming]

@@gutika113 Literally used to stop terrorism and half the video is talking about detecting bombs however you see this as a negative? Kinda sus bro

[@KevinOrIsIt]

He said laser light at 7:37, 8:01, and 8:27. laser is an acronym for light amplification by stimulated emission of radiation.

[@gm_construct_13_betaexplor38]

@@KevinOrIsItlaser is also a noun, what is your point

[@takenuser2k]

Matt was 100% right about most people not sitting down and read a scientific journal. Your channel is proof enough for most (I feel like). I know I have never been like "Hmm. How do I measure the tiniest forces in the universe?"... but I still watched your entire video. And like he said, the problem isn't the science itself, it the communication. Being able to actually SEE the effects/proof of what is being talked about is a much easier way for media to convey their information.

[@llKaiserx0ll]

That guy needs his own youtube channel.

[@hexisplus9104]

The lazer doc guy? Probably knows enough to.

[@thePronto]

He's too busy.

[@CYBERCATXO]

He is Mark Rober tho

[@Bill22886]

@@CYBERCATXO hahahahahaha Almost

[@azgarogly]

He has much more important stuff to do than entertain some million people sitting on their toilets

[@fishnsyd]

These NIST videos have been fascinating. There’s nothing better than hearing straight from the experts who also happen to be engaging and interesting people!

[@13lckr]

With the laser sheet, I wonder if using several different laser sheets of different wavelengths stacked closely together, you could analyze the color of it to model the flow of the air over the table in 3 dimensions.

[@DKFX1]

Had the exact same thought. Oddly I am very familiar with this specific visual phenomenon because it occurs naturally in my home on a sunny day. If you have a dark room filled with smoke and there are rays of sunlight making it through your black curtains then this effect will be very clearly observable.

[@RikKoedoot]

Super cool idea, though wouldn't like a blue sheet in front of an orange sheet make the orange sheet not visible for the camera?

[@kseriousr]

@@DKFX1 Ever since I saw how much dust particulates are hovering in my seemingly clean room, I was never quite the same. Even in our most hygiene, we're filthy 😄.

[@starstuff11]

@@DKFX1 yep scattering

[@Nielsquake0]

@@RikKoedoot Rapidly pule them or alternate the wavelengths and you could easily make probably a 1 meter long one with spacing of like 10cm or less per laser sheet at reasonable refreshrates depending on pulse lengts and camera sensitivity. Would be cool to have a 3D real time particle map at high resolution to track air current but I gues just simulating it would be more efficient

[@mateus_bandeira]

This guy should have their own KZbin channel. I could listen to him talking about stuff for hours.

[@proph7543]

@@gonelucid The guy behind the camera is the usual host and the owner. I don't know much about the guy who does much of the presenting here, but I assume that they're just a researcher in some government lab.

[@Lk95rulez]

@@gonelucid *isn't

[@kjohn5224]

their own? like a group of people?

[@VK-sz4it]

This guy gives vibe of a Gerald Batler's character from "Law abiding citizen". First time in my life I see someone who could be that guy in real life.

[@WLF0X]

But he actually has a real job

[@kyrillos6677]

The laser sheet method definitely makes me think of the moment a sun light beam enters my room and I first see small dust particles floating in that beam.

[@connorvanhelsing4768]

Yess! I've also blown vape clouds into the same beam to see air currents!

[@tetrabromobisphenol]

It's exactly the same effect, just with an incoherent light source. If you're not trying to measure 3D velocity but rather just visualize particle patterns, it doesn't matter what type of light you use.

[@ComradeMario]

That's Tyndall effect

[@glitteringstar6059]

yea I hate that cuz then you realize how much dust is in your room

[@last_avenger]

@@glitteringstar6059 same here

[@n.s.wickramanayaka7056]

Matt Staymates' presentation skills are truly amaizing. explanations are crystal clear and not a single ummm in the entire video.

[@georg240p]

5:20 ummm

[@yourmommashouse]

@@georg240p not matt

[@MattRose30000]

19:33

[@showalk]

There's one at 10:20 :D

[@GriffinZambia]

*Ok_Dont_Read_My_Namess* ....

[@NoWorldOrd3r]

I have the attention span of a chihuahua and was focused the whole video. Awesome work!!

[@tim40gabby25]

Um.. what's the attention span of these little dogs, then?

[@wrobelda]

@@tim40gabby25 definitely not long enough to work in this lab!

[@350c10]

That says so much about the way that guy communicates. It had my attention throughout

[@Prajjwal4242]

Wow what a comment

[@kurtnowak8895]

Good boy!

[@nobody_expects_me]

You with Kurzgesagt are in my opinion the overall best scientific educationnal channels ever, and I feel so priviliged to be able to watch those videos for free.

[@0x45Swims]

Kurzgesgat is billionaire propaganda

[@thejericho]

kurzgesagt is not very objective, they say what their sponsors want them to say, and it so happens that most of their videos are sponsored by Gates. some ppl on yt made videos about this

[@lisandroCT]

So you like propaganda.

[@nobody_expects_me]

@@thejericho I mean yeah, the one the man made viruses was pretty shady, I certainly did not like that one. But there are some videos that are not deserving the hate they get, and even the most controversial before this one were quite well argumented and were were overall well put together.

[@jm9371]

Clear, concise and fascinating. This content blew me away.

[@aampudia8]

but it blew you how far away?? like, with how many particles?? can you show us with your schlieren setup?? hahaha

[@matthewp4046]

Night and day vs that helicopter drop video

[@cagneybillingsley2165]

i can't help but think the guy is a liberal wimp because of his prey eyes, his sleeves being short like that and him not wearing anything under his sweater

Absolutely agree. Its mesmerising how well done this science is. I know this is generalizing but i kinda feel like this is how science should function.

[@nedludd7622]

This guy speaks better than 90% + of KZbin site hosts, including the one here. Example, he doesn't throw in the word "like" uselessly as this host, and most others, do.

[@seansampler6808]

I don’t know how you and your team have been pumping out videos this quickly but thank you!

[@SimulationWithDaniel]

They upload more in december since it gives the most ad revenue

[@dcamron46]

@@SimulationWithDaniel why is that?

[@noahverreth5280]

@@dcamron46 It is the end of the year, and quarter so if companies see that they have some yearly budget left, they can use this money for advertising.

[@GriffinZambia]

*Ok_Dont_Read_My_Namess* ....

[@unknowntimelord9557]

These recent videos were all related to NIST. They got much material out of that visit

[@ericswearingenmusic9967]

That dude absolutely loves what he does.. and takes huge pride in his work. Not to mention. He is an awesome presenter/teacher.. hope to see him more on the channel

[@arabknight82]

This was the area of my research ~10 years ago. I was very pleased to see how this was presented and explained in this video. Well done!

[@newbie4789]

That laser screen is such a good way to make cool live wallpapers

[@hypno743]

okay jackson

[@Anurag.Ganguly]

@@hypno743 okay boomer

[@mrmasrawy92]

Dude keep those thoughts to your SELF!!

[@kirkydaturkey]

13:38 yes! Dude thought the same.

[@shredder8525]

Till you go blind XD, there's a reason they had laser googles on

[@electrojag1]

I love now knowing the intricacies of the dog nose. it’s always been known (to me) that dogs have amazing smell, but to see why gives me a whole new appreciation 🐕.

[@aeremthirteen2771]

there was no why

[@chucknorris3752]

They have one reason why, I suppose. But they didn’t talk about the actual olfaction itself.

[@forget2bhuman993]

' (to me) '? like that isn't common knowledge?

[@forget2bhuman993]

@@chucknorris3752 because this is about airflow and such. not neuro science

[@aeremthirteen2771]

@@forget2bhuman993 because you said so, right? Or..? Director?

[@zombieowen]

Imagine using this for factories and workplace safety. Hazards caused by house fires or burn pits. The math and physics of airflow is fascinating and making it visual really hits home. Do dogs have the best sense of smell in animal world? What animal has the best hearing, the best vision?

[@ThaBeatConductor]

It's always really hard to answer a lot of questions like that about nature because everything is so specialized. For instance, by our visual standards, dragonflies have terrible visual resolution, but they have a 90%+ success rate for hunting, and have also remained relatively unchanged for hundreds of millions of years. Another example is the mantis shrimp. They have the widest visual spectrum of any animal so far and are the only animal that we know of that can see polarized light.

[@ngcastronerd4791]

@@ThaBeatConductor Firearms as well. Military types using firearms regularly are exposed to incredibly noxious fumes as was demonstrated. Designing guns that redirect the gases away from the shooter will greatly improve this.

[@usmh]

Eagles and falcons have often been said to have the best (meaning sharpest) vision, being able to spot a rabbit in grass from a couple of kilometers away or something. Bears have a notoriously good sense of smell, having a nose size advantage over dogs. I don't know about the best sense of hearing, but big whales have been said to be able to communicate with other from different sides of the world.

[@ThaBeatConductor]

@@usmh The one about whales is less to do with their hearing and more to do with how sound propagates through water, especially at certain temperatures and pressures. That and whale calls are super mega loud.

[@NEO_MusicProductions]

this technology is kind of scary for me. I am a DJ, and let´s not get into if I use substances or not. Let´s focus on just me being on stage, people snorting drugs left and right, even if I didn´t touch any drugs, these test would show me as contaminated. The question is, how do we differentiate between just a bystander, and a trafficker, or a manufacturer. If they just start screening everyone, i bet your ass, every single person who enters a club/bar is going to be contaminated. I don´t like this idea very much... for bombs, yeah go for it, but for substances, they really need to set some standards to avoid false positives...

[@gutspraygore]

This video is amazing. It's not only very specially informative, but the enthusiasm behind science is incredibly infectious. So, thank you to you both. Rich, you are a great educator as well as you Derek.

[@dotacow22]

Its amazing how much elegant designs there are in nature, from the Japanese train engineers who modeled train fronts after bird noses to reduce sonic booms and noise, to this, its just gives you hours of stuff to think about.

[@shellderp]

You see a lot of "AI generated" solutions to various problems these days. Nature is just that learning and adaptation process at a much larger scale

[@redline589]

@@shellderp Of course, every house is constructed by someone, but the one who constructed all things is God.

[@l.rod.8558]

@@redline589 bro go away

[@kkuhn]

The prime mover is a flawed ideology

[@user-sy4mp8hq6i]

@@redline589 You don't belong here

[@abbymeehan7739]

This guy is such a natural presenter!

[@MartKencuda]

Which is odd because the video makes it look like he's the only one that works there lol

[@abbymeehan7739]

@@MartKencuda My dude has just been dying to show someone his lab!

[@throwaway3756]

@@MartKencuda Don't worry., he wrote "a code" to replace them all.

[@volthunter3]

yeah he almost seems trained, like his job is to convince people of his science more than actually doin science, i wonder why anyone like that would be employed by that company and not a larger group that would fund a talking head, idk weird huh lol lmao xd hahahaha he's very good

[@timbatimba]

@@volthunter3 people that are passionate about what they do tend to behave like this.

[@gemo9561]

Wow the passion in this guy is next level. He REALLY loves what he does for a living.

[@hutchwilco]

This was easily one of the most interesting videos I’ve seen in about 15 years of watching KZbin. This struck directly at the types of things I think about all the time - micro fluid dynamics - super super interesting. Thanks! Lucky enough to have visited the NIST lab in DC (for energy related topics)

[@SourabhDas95]

My capstone project in university involved using laser light sheets in front of fume hoods to check flow and test their effectiveness and make sure fumes weren't escaping. That used 3 lasers, red, green, and blue, at different distances from the face of the hood to visualize multiple 2D cross-sections and better capture a pseudo-3D visualization. This video brings back memories of that. Really cool to see the laser light sheet technique being used in all sorts of forensic and disease transmission research applications.

[@mycosys]

why do they not scan the sheet back and forth for a 3d area?

[@NATESOR]

@@mycosys it'd also look rad af

[@NATESOR]

@@mycosys it'd also look rad af

[@toolbgtools]

using different colors is great idea. also, we can further extend it by using multiple wavelengths of light. it's actually like 3d sheering

[@toolbgtools]

@@mycosys we can't because turbulence is chaos and moving back and forth will take some amount of time

[@NBD300]

Notice how quiet Derek Muller was? Rich Press is amazing at his field.

[@juicedelemon]

@@Caseyneistat3010shut up

[@hamoodhabibi]

That's not Rich Press, it is Matthew Staymates

[@ElRel]

Guys like Matt are what is necessary to get folks excited about science again. He does not talk down or patronize like many science communicators. He is not afraid to be seen to get excited about what he does.

[@fprintf]

This has to be your best video to-date IMO. Informative, relatable and visually so appealing. Well done!

[@SirWuffleton]

There’s an art to distilling a technical subject into just the right amount of detail for a layman with extra detail sprinkled in at important parts for those with a deeper understanding. It’s a balancing act between providing enough detail without overwhelming those not familiar with the topic. Matt absolutely nails this and it’s always cool to see professionals in other technical fields using this strategy as it’s something I use frequently in IT!

[@anuranjo4809]

Some years back I took a tour of this very lab at NIST. I saw Matt Staymates and his research division lead Greg Gillan. They were working with 3D printed dog nose for explosive detection back then and the way Matt explained this to us was cool. Fascinating.

[@GriffinZambia]

*Ok_Dont_Read_My_Namess* ....

[@chimkinNuggz]

They're trying to take jobs away from good boys!

[@basilbiscuit2735]

Interesting! How did you get that opportunity? Is it something they do often, or was it more of a special access type of thing?

[@tomatomaki]

​@@GriffinZambia My brother, the OP's story is far more interesting than your half-assed name.

[@MegaSahil009]

So far one of the best informative videos on your channel! I mean the expert really was explaining everything instead of giving just bits and pieces and then derek (veritasium) helping us understand through his interpretation and understandings. That's not bad either,and veritaisum is the person to credit for all the info and experiments he brings to us, no doubt! But yeah we all agree this one hit different because the expert was really thourugh to detail every of his experiment and explain the scenario where it could be applied. Amazing great job both of you! Need more of such videos, and you may also collab with him for a part 2! That would be so great

[@bassett_green]

Matt is a phenomenal presenter! You can tell how much he loves the subject matter

[@victorferro6862]

That guy explains everything really well!

[@teflonmac5082]

He is more articulate than some leaders of the world today.

[@zero4961]

@@teflonmac5082 look at his eyes. They move around like he is scanning his mental database. its insane!

[@spicychad55]

Looks like Nose what he's talkin about!

[@LevJ0y]

I love to see how passionate Matt is about this subject

[@defeatSpace]

Now think about how much tax money he's wasting through various inefficiencies and technical overtime.

[@rajkishore95]

@@defeatSpace lol shut up, sitting on your fat butt complaining about scientists who do good work

[@legathar8558]

@@defeatSpace I love making claims without evidence

[@xXBRgamesXx]

@@defeatSpace what do you mean by this?

[@mycosys]

Devotees of the cult of authoritarianism are always ful of zealotry

[@R1987R]

I was watching this on my TV and had to go on my phone to type this. But apart from this being an awesome video, that dude has amazing presentation skills. His enthusiasm and knowledge just captivate me and he hasn’t lost my attention for a second. Great find Derek!

[@danieldey]

Finally I understood how the Schlieren setup works. Thank you Derek!

[@Failzz8]

Very fascinating, but also incredibly scary to think about how this could be used to track pretty much anything anyone is doing.

[@Shrooblord]

Myyyaahhh but the costs involved and manpower / hours needed to develop AI to _replace_ the manpower in getting all of that organised is (still) pretty unfeasible. Then there's admin, 'some incompetency', conflicts of interest, funding, etc. etc. Not to even mention any counter-movements or all that work getting cut short for whatever reason before it gets a chance to properly be launched Whenever you think about something scary and all-encompassing like that, also think about how "clunky" most things are we do on a general basis... and then try and marry the two concepts x)

[@jasondashney]

@@Shrooblord A smartphone was very very clunky in 2000 but by 2012 they were ubiquitous and essential for modern life. A dozen years.

[@Shrooblord]

@@jasondashney that's pretty true! Then let's keep paying attention and using the tools at our disposal to advocate for what we believe in, and fight what we don't...!

[@richkroberts]

Derek’s work is so well done, even when something doesn’t seem that interesting (going by the title), I always end up learning a lot, even if I think I know the topic. Thanks for posting such high quality content Derek!

[@zechen6879]

Finally a veritasium video where I understood 90% of the stuff instead of not understanding 90% 😅

[@scientia_potentia_est]

The work done at NIST and ISO is so underrated. I feel like there should be like a national holiday to celebrate the life-saving work these guys do.

[@Shrooblord]

Now that is a really cool idea. International Standards Day x')

[@nicklame2647]

Towards surveilance society we go, soon your farts will be analyzed in real time, *pling* you will get message that your health insurance has been terminated.

[@sirBrouwer]

@@Shrooblord do know that ISO stands for International Organization for Standardization because La France. but that must be the most expensive party there is when every item must be a ISO item.

[@vigilantcosmicpenguin8721]

Looks like ISO was established on February 23, 1947. That's as good a day as any for a celebration.

[@kylehenline3245]

I'm amazed at the enthusiasm of all the scientists at NIST you have captured. This whole run has been so informative about careers in STEM, absolutely fantastic stuff. You and other educational creators are the best of internet.

[@David460]

It's so amazing to watch an expert talking about his/her field.

[@antimony-5172]

I love this video! The techniques, procedures and experiments at NIST are incredible, yet enlightening.

[@ghgracia85]

That dust spread is why cross contamination is so challenging for celiacs

[@kjyost]

@Aluzky I would suspect the answer is wheat flour 🤦‍♀

[@kjyost]

@Aluzky I can infer the reason is that wheat flour, a fine dust, could get on everything as they show here with talcum powder, thus getting gluten into celiacs intestines. Celiacs have a genuine diagnosed medical condition that even the tiniest amount of gluten can cause huge inflammation. I suppose you could not see that connection. Alas.

[@LostMekkaSoft]

i started to grow carolina reaper last year and i am very familiar with these dust movements by now, because when you dry chili and grind it to a powder, you always have these particles that stay in the air. and you dont want to breathe in this stuff, believe me xD i didnt have a fancy setup like this, but i used a bright light to illuminate the larger particles, so i could figure out how to move in a way to not accidentally pull these particles towards me ^^

[@in5aneguy597]

wouldn't something like a fan help with this issue? preferable outside/towards the outside so that those particles will get pushed away? or the opposite something like a vaccum cleaner to suck in those particles?

[@Djuntas]

@@in5aneguy597 Or make them wet as you cut. Water kills dust movement anyway.

[@lordgarion514]

I'm a chef, and a few weeks ago the other chef threw a handful of blackened seasoning on a piece of fish, literally seconds after one of the exhaust fan belts came off quietly. I walked right into an invisible cloud of it. In my eyes and up my nose. 🤬

[@Sagittarius-A-Star]

Are you actually eating them or is it just for the thrill?

[@LostMekkaSoft]

@@in5aneguy597 that was my first guess as well, but fans create too much turbulence and then the particles disperse evenly, making it hard to breathe :D i settled on gently waving the air away from me after opening the mixer unit, while having an open window nearby. of course, a professional ventilation system that just sucks in the air immediately would be best, but that is not available for me ^^

[@970357ers]

The candid explanation provided only comes from knowing the A to Z of your subject/craft. Great video.

[@Abishek_Muthian]

This NIST series is a gift that keeps on giving.

[@gersonperez3781]

Finally, the "Elevator Fart Detector" invented.

[@collectorguy3919]

...experiments at the holiday party

[@MegaSahil009]

Hahaha

[@KTStrategic]

Fascinating video! But a point of clarity, (medic here, for reference) his comment about Fentanyl isn't accurate; it takes a significant amount of inhalation exposure for fentanyl to be absorbed intranasally - although it looks like a lot in the video, it's still highly unlikely to be an exposure risk.

[@mycosys]

espescially to the soryt of person who would take that job, someone likely to have a very high tolerance from repeated exposure prior to taking the job (ie a veteran user)

[@TehMuNjA]

yes, that line was pure BS and yet just taken at face value without question, a common talking point in the bogus war on drugs police propaganda

[@rdizzy1]

You can absorb it into mouth tissues as well as into your lungs for direct exposure though. Most people breathe at least partially through their mouths, not solely through their nose.

[@Chibs]

@@rdizzy1 And that somehow makes up for the giant dose neccesary to ovedose in the first place? The idea that one could overdose through exposure like this is simply false, no two ways about it. Sad to see Veratasium perpetuate such copaganda.

[@TehMuNjA]

@@rdizzy1 the surface area of the lungs is extremely large and made specifically for transfer into the blood stream, i'm no expert but i would think any absorption through mouth tissues would be negligible in comparison

[@svenvolwater5473]

I absolutely love the way how matt explains this vid, love it!!!

[@MathTutor1]

Great work as always. Excellent explanations. Keep up the good work!

[@skjetnis]

You keep finding these incredible people who just loves what they do so much, and in return we get this amazing content. Keep it up

[@niknik0815]

Dude, this guy was explaining so well and in such an entertaining way, I am glad you cut and added so little and kept so much original footage. Nice edit!

[@muxpux]

I “discovered” the laser light sheet long ago. I was sitting in a bar in my early 20’s. Smoking a cigarette. It was daytime, and the sun was shining. The bar had blinds on the windows, and sunbeams were shining through, creating “sheets” of light. My cigarette smoke made amazing swirling patterns in the light. Only took me nearly 20 years to become fully obsessed with fluid dynamics and visualizing the processes.

[@JimSim117]

This bloke is great. Clear, informative, and engaging.

[@Hopeinformer]

This is by far my favorite stuff on this channel. Thank you for breaking it down so thoroughly and sharing it.

[@d.bcooper2271]

“The FBI gathers evidence. Once evidence is gathered, it is turned over to the Department of Justice. The Department of Justice then decides whether it has enough evidence to present to a federal grand jury. In the case of the 1998 United States Embassies being bombed, bin Laden has been formally indicted and charged by a grand jury. He has not been formally indicted and charged in connection with 9/11 because the FBI has no hard evidence connecting bin Laden to 9/11.”

[@RjWolf3000]

I remember observing my dog doing this. We called it motor mouthing because they also open and flutter their mouth when doing it. If you do it yourself you will smell things you wouldn’t otherwise notice.

[@jesusdanielhernandez6304]

Yeah I actually started mimicking this method to try and sniff out feint smells. It really does work, although you definitely look weird while doing it 😅

[@lordgarion514]

But if you do it in public, people are going to look at you funny. They might even back away.

[@killerowire]

this comment section is gold

[@PeterGenovese]

I just tried doing this and smelled my neighbor's asshole. Pretty cool!

[@RjWolf3000]

@@PeterGenovese you are most likely just smelling your own breath.

[@RichardMerrill3Hawk]

Amazing! Fascinating subject, Matt explained everything really well, and it looks as if he came up with a lot of the ideas he's sharing. Also, it seems the laser sheet is a little like an MRI -- it shows a thin section of the air dynamically. Really great video!

[@little_lord_tam]

Everything about this video is amazing. Just wanted to share that. I loved every second of it

[@vickieurantian1554]

That's why dogs can get a sense of when you're supposed to be home from work based on how much of your scent is left in the house.

[@imveryangryitsnotbutter]

Wouldn't it be easier to just notice where the sun is in the sky?

[@LividAF]

@@imveryangryitsnotbutter Not if they are stuck inside of the house. It’s also probably easier for them to use their strong sense of smell. I would imagine it’s similar to how we would try to find the source of a smell in our homes. Like if someone was cooking, we could tell by smelling it through the air.

[@SnailMan63]

@@imveryangryitsnotbutternot to mention the sun changes position in the sky at times throughout the year

[@Fisher_007]

My theory has always been that they have a very good inner clock. My dog gets dinner at 6pm and he starts nagging me between 5:30 and 6, irrelevant of the sun since for example sunset is at 4pm now.

[@K40005]

Most animals have a very good body clock (my cat will pester me for food at almost the exact same time every day with about 10 minutes difference being the furthest from that time) (which is 4:30)

[@Wormweed]

If all teachers were like Matt we would all be way better educated, or learning the same in less time. Listening to him was amazing.

[@crypticTV]

8:13 theatrical fog 9:50 skin cells 11:30 12:30 14:30 explosives tracing 15:22 drone use 16:00 18:00 18:30 3 letter agency

[@hanispeace8006]

Im procastinating on my thesis, glad that I found this video because it makes me motivated again. The power of knowledge always makes me motivated!

[@bartolomeothesatyr]

Hey Derek, how about some Veritasium about the measurable harms perpetrated by prohibitionist regimes? imagine if all the resources and mental efforts that go into prosecuting people for self-medicating with illicit drugs were instead directed toward improving public health and early childhood education.

[@harrybeasley6608]

Shout out to this guy. What a natural behind the camera. What a natural educator. Nice vid Derek. Loved it, thanks

[@deusexaethera]

This dude is a one man forensics lab. Amazing.

[@SPNsherry]

You can tell that Matt Staymates is passionate about his job, he's also interesting to listen to, more of him please.

[@pieterpennings9371]

Matt deserves all proceeds of this video, damn that man can keep someone hooked from beginning to end. What a speaker

[@luizfelipemelo4477]

This video was absolutely incredible, I got kinda sad when it ended. You can really feel Matt's enthusiasm and how much he loves doing that stuff. Amazing content, Derek

[@esmaeil9478]

Always love your videos! Very nice, concise and to the point. Thanks

[@jordansparrow8061]

This is one of the best videos I've watched on KZbin in all of 2022.

[@mattstyles2498]

I like how this guy is definitely passionate about his work and is great at explaining it.

[@valmikg1]

Impressed by this guys presentation skills, ability to condense material to lay-terms, and be passionate. Kudos

[@rollingsausageltd]

One of the best videos in this channel. Super clear. Very cool lecturer

[@mihneadutu623]

thanks to you're channel and all you're hard work , many people learn and understand so many things we didn't know about ! thank you ! ❤️🏆👍

[@LunaMapping_KR]

This guy is a great talker and teacher, I’ve learned so much on this video and was entertained the entire time, glad to see the technology used behind the scenes get a spotlight and be appreciated by the public

[@zer0nix]

One of the best explanations of schlieren imaging! I want more of this guy!

[@Ytryanymore]

I like how simple yet complicated the set up is like anyone can build it but know where the exact points to get the best image definitely a challenge.

[@akarp111]

because we live in a world of vibrations! :-)

[@lukasausen]

linus tech tips made a schieleren imaging thingy to mesure graphics cards airflow wich is preatty cool tbh.

[@Ytryanymore]

@@lukasausen I just seen that crazy

[@sortedsortof3474]

As always, a fantastic way to learn things. Thank you.

[@chiepah2]

The phrase "There will always be a piece of me with you" takes on a whole new meaning.

[@markwright3161]

Ah yes, that few hundred skin cells stuck in your lungs from them :)

[@PierceArner]

Biomimetic Design is one of my all-time favourite things, because you're taking systems that evolution has refined at various scales and then implementing them into technology to vastly improve its effectiveness in ways that we'd never be able to do with just normal iterative testing or conceptualization.

[@GriffinZambia]

*Ok_Dont_Read_My_Namess* ....

[@anteshell]

Evolution does not strife for perfectness. It strifes for adequateness. When some feature is good enough to overcome the selection pressure, there is no more pressure to evolve and the further development will be stagnated. In school terms, more often than not this results in minimum grades required to pass the class, but far from actually learning the subject and becoming good at it. While we find very good and novel solutions to some problems from nature, it's not as much that the nature does things good as it is that nature goes around solving these problems very differently than humans are used to think, and due to sheer amount of different solutions in nature there are bound to be some good ones. This is the case of infinite monkeys with typewriters. When we find solutions from nature, it's more like combing through the text those monkeys write until we find something good.

[@captainunknown2839]

@@GriffinZambia stfu who asked

[@hridoy8021]

This was one of the best videos you came with Derek! Love that guy, it feels like he's so passionate about what he is doing. And his explanations were so smooth! Love it 💜

[@cybertones942]

Always loved the sheet one because I see I a lot with light shining through cracks in curtain or door. See all the little dust floating in the air or smoke patterns mostly for me

[@elfofrit]

Superb video. Last summer I made a project about the Foucault knife edge test and the schlieren effect. The qualitative over quantitative data turned me down at first but seeing these applications, explanations and visualizations made me proud of my work. This topic is so rich, interesting and fun!

[@justayoutuber1906]

Wow - Matt is one of those rare individuals that is really smart and great communicator. I would love to see more videos with him explaining things. NIST appears to have some great people working there!

[@GriffinZambia]

*Ok_Dont_Read_My_Namess* ....

[@BuzzkillZone]

So I'm really loving this NIST series. I had barely heard of them before the series started, but the more I hear about them now, the more I am amazed.

[@themr_wilson]

Part 1 of Indefinite, right? This is greatly intriguing - thank you, Veritasium, thank you Matt Staymates, thank you both for your inevitable continued installments in this cutting edge field

[@mduvigneaud]

What an amazing video! Matt is so well spoken and explains everything so well! And just to be silly: while watching the video I felt compelled to pull out one of my green lasers and some of my laser optics (including a cylindrical beam spreader of course!)

[@polarpaw224]

I’m happy to see so many others also experienced awe over the experience of listening to Matt. I was wowed by how enjoyable he was to listen to. It drew my attention, specifically.

[@Sad_King_Billy]

I've seen this imaging technique explained several times and it still looks like a magic spell. How does someone look at light and think to chop it with a razer blade? Incredible. Loved the video!

[@JP-lz3vk]

What he's doing is polarizing the light, which is why you can "see" the changes in density next to the mirror

[@d.e.7467]

Yeah, the razor blade is a remarkable addition. It's a very low tech solution.

[@lordgarion514]

Sometimes you just gotta cutta beam. 😄

[@tetrabromobisphenol]

It's an interferometer. The razor blade edge causes diffraction. It's not used to block light, it's used to measure phase differences caused by small changes in the index of refraction in the sensing region.

[@tetrabromobisphenol]

@@JP-lz3vk Hate to say it but no, this is not due to polarization effects. Schlieren images are effectively phase contrast.

[@bewhitey]

I live down the road from a NIST lab in Boulder....always wondered what they did there. Very cool!

[@454jamie545]

One of the most fascinating videos ever and the professor is a phenomenal teacher. Thanks for this one. ❤

[@Scott-.]

Matt is so engaging, such a great speaker! Please get him to teach and show us more!

[@westzed23]

I found this episode amazing. I have not worked in forensics in 30 years, and it is so great to see what new methods are being developed and used.

[@EpicNexusStudios]

Very articulate and present in providing explaination about how all this works. Guy could make a Art channel with just the laser field and particulate flow.

[@davidshelton1898]

Expanding on the dark edges showing a louder sound; you are seeing density. Given air is homogenous, the stronger the shockwave, the more air it can smash into a small space. With a good control sample and good resolution, you could create a direct pixel gray-scale to decibel to psi conversion at w/e resolution your setup can record at. Pretty amazing when you consider the setup in the video had enough control to be replicated with ease, really gets the imagination going knowing this kind of stuff is being used and shared across the internet, another amazing find good sir. On a side note, I love the beautiful patterns inside the dark ring. Strikes me as strange that a 2d Slice of this 3d wave looks a lot like a ripple you'd make in the water.

[@jesuschrist3872]

This is a great comeback after last video! This one really has the quality that Veritasium is known for 👌

[@GriffinZambia]

*Ok_Dont_Read_My_Namess* ....

[@Neurofilia]

This is one of the most beautiful Veritasium videos in all sense: a lot of science in it, beautiful visualizations, good research, good explanation... just amazing !

[@CaptDicker]

Incredible presentation, thanks for sharing.

[@mrtmat]

Honestly, everything in this video, including the ad, was great.