These Particles Flow Upstream Instead of Down

Is it possible to for things to flow against the current of water on their own? In this video I talk about upstream contamination and talk about the mechanism behind how particles can actually flow upstream against the flow of water on their own.
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*Any experiment you try is at YOUR OWN RISK. The Action Lab assumes no responsibility for any injury if you attempt anything you see in this video or on The Action Lab channel.

[@meliodas11]

*So what if i pee into that contaminated water?* 😱

[@odned8168]

HOLY SHIT

[@mrkitty777]

You get a kitty 😼

[@chiranjeevsahoo4960]

Bacterias: helo

[@Dyltheboy]

Uhhh

[@ionymous6733]

you piss at a high enough velocity (more of a jet than a pour) and far enough from the water that you won't encounter this phenomenon.

[@_Killkor]

This is just a physics collision glitch. It will be fixed in the 1.2021 update.

[@gameingplayer1352]

There is already a virus in this version (1.2020) I don't want to see anything else

[@upsilan_mitstrima]

@codey morganti nah man, the devs haven't been updating this kind of stuff

[@Versuffe]

It’s the 130000000000.2021.1.1 update on 2021 January 1st. God says he is working on stuff. Wonder.

[@Versuffe]

And there was a new update on 1300000000.2019.12.31 that improved virus ncov-19 so it wasn’t dormant. That was a bad update, but god thought it was a harmless creature that was dormant.

[@vicnent651]

@@gameingplayer1352 yeah they gotta fix that

[@boswell255]

This effect is how they add individual molecules of flavoring to La Croix.

[@thibaut5345]

?

[@AshrZ]

@@thibaut5345 Because La croix has no flavor

[@SoulDelSol]

@@AshrZ La croix has many flavors

[@jf2801]

@@SoulDelSol many flavors, but no flavor. As in it lacks any taste.

[@AshrZ]

@@SoulDelSol scents* the flavors have smell, but no taste. I bet the can is yummier.

[@D-Man_Jam]

The particles for some reason: *"My goals are beyond your understanding"*

[@tomsterbg8130]

@Lee Ruan it doesn't matter if it's h2o or any other *liquid* though

[@dingo_ate_my_spaghetti5454]

Minecraft water physics is that you?

[@metsys7928]

Yes

I wonder how can we make a tree hover in the air.

[@jomelforteza1700]

What if minecraft is only an early access to real life simulation

[@dingo_ate_my_spaghetti5454]

@BOT NOOB yeah, but I got my revenge tho. I grilled the dingo and ate it.

[@21dxminic13]

:o THE LEAVES ARE PLAYERS

[@Nawmps]

⚠️ SEIZURE WARNING!!! ⚠️ Quickly strobing lights from 4:12 to 4:35!! It's not exceedingly bright, but it messed with me enough to worry about anyone else who may suffer from epilepsy!

[@sebaspi]

This effect is caused by the strobing light when recording slow motion with a cell phone, i did not know but its really enough to cause epilepsy?

[@Nawmps]

@@sebaspi It was enough to cause me to feel strange while viewing, so I thought I'd play it safe and share this comment :)

[@sebaspi]

@@Nawmps yeah absolutely im just amazed because its something very common and i guess if thats is dangerus for some people we should be more conscious.

[@rosemarymetallic9741]

thank you so much for the warning

[@alphazeroseven]

You are officially a legend

[@Aufenthalt]

Absolutely amazing!could you put particles in alcohol and pour water?the marangoni effect should be enhanced.

[@generalginger7804]

what about soap water??

[@Desam1000]

@@generalginger7804 yes. what about it!

[@sirpoopsalot5285]

Note that the lower surface tension may cause the particles to sink unlike on water. But this would certainly be a cool experiment and with the correct "contaminants" we could see it work.

[@helloworld9742]

Tell me y I saw macaroni effect 😂

[@yonisteubner6078]

Maybe with color or does it only effect flowing particles?

[@Hyraethian]

As a former water treatment operator i can say that we have a hard rule that fixes that: The air gap must be at least twice the diameter of the receiving pipe or container So a safe gap for a measuring cup would be something like 13cm (five inches), depending on the size of your measuring cup

[@YouTuber-mc2el]

The construction industry also has a variation of this rule you mentioned. When running drains from a prep/wash sink the drain pipe empty's into the floor receptacle at a distance above the floor drain per the pipe size. Thereby eliminating the chance of bacteria and the like traveling back to the prep/wash sink. Crazy stuff. Cool video.

[@papag5303]

In Germany it's at least 3x the inside diameter of the pipe

[@keller8064]

Wouldn't it be easier to demonstrate this with a beaker containing alcohol and food coloring and the cut-up can with the clean water?

[@brunolisenko8488]

That's a clever proposal, im gonna try this at home, thks

[@lgab]

Easier, but not as mindblowing, as there's a chemistry going on there which we don't have any every-day intuition for. Conversely, water into water is an every-day thing which makes it interesting.

[@keller8064]

lgab True!

[@-danR]

Either way, I wish he would _explain_ phenomena from first principles rather than just throw X-effect and high surface tension and low surface tension into the mix as though jargon were sufficient to the understanding. "The atomic bomb works on the fission effect where you have all these heavy atoms and a chain reaction and stray neutrons and..." ...would never have landed you a job at Los Alamos.

[@Ktulu789]

1:10 Ok, I didn't expect to learn something from Argentina today, let alone finding a pack of yerba in The Action Lab! Saludos desde Argentina!

[@Ktulu789]

Now I know how the yerba gets in the kettle!

[@mystcat3]

What about "Tereré" from Paraguay?

[@Ktulu789]

@@mystcat3 I guess that since both yerbas are about the same in size and shape, the effect would happen too. Only difference is tereré yerba is less dried and stronger. It's hard to find tereré yerba in Buenos Aires. I would like to find chimarrão erva too.

[@vicentealvide1218]

No hablan los dos español?... Porque de responden en inglés jajajaj

[@mystcat3]

@@vicentealvide1218 Para que la gente que lea los comentarios puedan entenderlos, ya que la mayoria que ve este canal son de habla inglés

[@zreolmeannin]

I recently accidentally experienced this effect while brewing pu-erh tea and was unsure of how there’s leaves inside the thermos, I suppose this may be the answer

[@jeko464]

if you can brew the tea a few years before, it will called ( your name ) affect

[@zreolmeannin]

Kaai Ting Jerry Kong didn’t understand

[@Michelino_M5]

@@zreolmeannin he's saying that had you found out a few years ago, you could have been the one to officially discover the effect. ngl that took me a while to understand lol also that's wrong because the effect is called "upstream contamination effect" and doesn't have the name of the student who discovered it. so the dude really failed hard here lol

[@zreolmeannin]

M5 yeah got it after some time, that language though...

[@tangent_x1238]

@@Michelino_M5 that might be because the student himself didn't understand what's happening so told his professors before trying to understand the phenomena himself

[@jordisreallybored]

Particles: *uno reverse card*

[@RPDC-ng8ej]

*Jumps on water*

[@nahulseyon54]

A poop finds its way into the flush tank.

[@blockcraftermc4612]

When i saw this in my childhood While playing with water Mini-me:wut is dat?

[@nahulseyon54]

@@blockcraftermc4612 😄

[@someonethereto]

Just want to take a moment and THANK YOU, for giving me a better direction to think.

[@roughwoof]

*In other words... Don't pee in rivers or lakes.*

[@dumbass6329]

Or anywhere

[@roughwoof]

@Derpo *In other words, "don't pee in rivers or lakes." Are you happy?*

[@surisalas1326]

Oh wait..... we pee in toilets right? So the water or the toilet....... I ummmm aAAaAaA now I’m scared

[@LavyaBhansali]

This is correct Dont river or lake in pees

[@nova_vista]

* with your junk 1 cm above the surface

[@joltuk]

Looks like I need to be really careful what I pee into now

[@sovietbot6708]

You especially should be worried because there is a parasite that swims up urine streams into the urethra.

[@damienreed]

@@sovietbot6708 well, maybe pee from one spot to other so they can't swim into it?

[@skateordie9628]

🤣

[@StressedSkizo]

Make yourself have a shotgun stream

[@noe616]

Yah, don't pee onto an electric fence.

[@tjsudac]

His neck is smiling with adam's apple being the nose.

[@01DOGG01]

LOL I just read this as I'm watching it and it's got dimples at 6:48.

[@prathamagarwal9869]

good observation bro

[@fundemort]

Anyone see Majin Buu or just me

[@nathanielburns6692]

Tomo why must you hurt him in this way

[@muymuymg71889]

Tomo omg yes

[@tom_something]

"Hey everyone, today I'm gonna be showing you why you should flush the toilet before you pee."

[@dawiejoubert2578]

Moron!!

[@practicalguy973]

Flushing don't mean clean.

[@anstropleuton]

😖

[@nahulseyon54]

A poo climbs up and enters the flush tank. The Action Lab: Finally, we found another intelligent life on the Earth.

[@912-pizza4]

Hehe

[@eamonia]

How on Earth do you consistently come up with all this crazy, cool content? You must never stop thinking and wondering and finding things out for yourself to share for the whole world. Thanks for sharing your awesome brain with us and answering so many questions that we never even thought to ask. Like, you can boil water in a blender!? I'm still blown away by that one. Good show ol' chap. Bravo!

[@imranp128]

My god I love this channel. God bless you action lab. Genuinely bringing knowledge to the masses. Action lab > TKOR

[@shelly-anncurwin7739]

The king of random

[@anon6474]

I would like to see the experiment with particles that do not float, it seems like it is just floating up, try with somthing that has neutral buoyancy

[@RandoniumTJ]

That's a very good idea ...

[@melonenlord2723]

Don't think it will work. He mentioned it has something to do with surface tension, so it shouldn't. We should try, though.

[@dawiejoubert2578]

Stupid. Go read somethin apart from mills an boone

[@balazsszalai41]

The chalk particles aren't floating (they have higher density then the water), so you have already seen it.

[@gxgaming7560]

I first thought it was buoyancy too, but then I realised that if that was the case, the particles would already be in equilibrium at the surface, so they would be moving with the flow (which is an additional force), and thus away from the spout, rather than against the flow and into the spout. Correct me if I'm wrong.

[@corneliahanimann2173]

I don't remember when I subscribed to this channel, but every time my curiosity gets me to click on your videos, I end up having a deja vu of why I subscribed. I just don't want' to miss out on what you're sharing because it always pulls me back to my fascination for physics. When you spend most of your time looking at books, you eventually just go with the flow of studying what's there forget that you once actually had a fascination for this stuff. thanks for that

[@Anonymous-xp7ze]

I didn't see the effect name in the comments, so here ya go: Marangoni effect.

[@cerebral3591]

Came back to look for this. Thanks!

[@rockyhooks3372]

Pro tip, just pour into the container from above your head so you get that 5 foot pour distance. Side effect; looks really cool

[@o-brogaming6237]

Hey man, love the videos, very educational! Keep it up.

[@bisforbara2314]

This phenomenon was haunting me as a child now you revive it as a real thing

[@konstantinosskarmoutsos5935]

Very happy to watch a video explaining how happened something "impossible" I saw some time ago. Thanks!

[@eamonia]

...and all the questions people ask about your experiments. Experiments that I never even theorized yet are pushed so much further! So cool...

[@RandoniumTJ]

I had this idea when i was a kid . And i thought it was a stupid idea . But now I'm happy that it was not totally wrong ...

[@CM-mo7mv]

It actually is completely known by anyone who has their senses. You can easily "smell" the flavors inside the clear remainder in a water bottle making it upstream from a syrup when you have poured the water onto it. That's not news.

[@RandoniumTJ]

@@CM-mo7mv that's right but not technically upstream ...

[@CM-mo7mv]

@@RandoniumTJ what? yea, i thought that people wont understand what i was describing. It actually is technically upstream ... Please reread my words with that information.

[@RandoniumTJ]

@@CM-mo7mv oh ok . I see that. But I am not an English speaking guy . So i might not be able to exactly figure out the fact ... I think you are trying to say that , the smell of the syrup adheres to the walls or the remaining water in the water bottle , although it did not have any sort of downstream contact with the contents of the syrup ... I may be wrong still ...

[@ezekieldominiquintal7556]

I think it is a combination of phenomena. By pouring the liquid, you thereby lower the surface tension of the surface of the liquid in the lower level. This results in 3 things. 1. Adhesion: Some particles will adhere to the one with higher surface tension while the others will sink. This is also possible because higher surface tension provide better ability to hold its shape allowing the contaminants to be "grabbed" by the imperfections of the downpour. 2. Pushing Motion: Some sinking contaminants are propelled upwards by the rebounding portion of the contaminated liquid when the contaminated liquid tries to reform its shape when it is deformed by the downpour. This may act as a 'pushing motion' propelling materials upward. 3. Pulling Motion: When the liquid being poured were to be stopped by tilting/retracting its container, the surface tension of the uncontaminated liquid that allows it to hold its shape may actually drag a portion of the downpour(along with some contaminants clinging on it) near its container. This may act as a 'pulling motion' to hold the shape. Combining these 3 effects may result to this 'Upstream contamination'. When some of the particles are grabbed by the downpour, these contaminants that 'adhered' are subjected to these 'pushing motion' and 'pulling motion' which, by laws of motion, are dependent on distance from its source explaining why it is more observable in shorter distances. Not to mention that if you also account gravity into the mix, gravity will be less pronounced it shorter distances and even lighter materials will produce a more visual experiment. Upstream contamination is dependent on distance, density, consistency, momentum, 'ionization' which may become integral in certain materials, some other unmentioned factors may also contribute but in less pronounce way. I'm not a science guy but this is how I see it. Pardon me if I failed to mention a more appropriate terminology in any consensus. I hope I get some feedback on this matter.

[@NetAndyCz]

Could you try this with some dye to see whether the source gets contaminated just from the surface particle or even the solvable ones (like the dye?)

[@ARPLATINUM]

Waiting on Destin to explain this in high speed detail lol

[@sharadkumarsingh4802]

#SmarterEveryday

[@tecker7454]

*Me, an Argentinian:* Is that Yerba? No, no way that can be. *Also me:* Oh, wait, it is!

[@SoulDelSol]

Ya t's made it's way to North American stores and been popular enough to stick around

[@aleismasanchez]

What brand is the Yerba Mate he is using?

[@juanfc891]

Vamo Argentina pa

[@ZReChannel]

siempre pensé que tomar mate beneficiaría a la ciencia

[@Simon-ph1nf]

This is very useful for people that work in labs and need to double check this does not happen in their day to day lifes

[@kavi642]

Who is that disliking this video which give us various information

[@Just_Sara]

I always learn something really new from you, thank you for showing all these interesting cool things you learn!

[@fortniteclips8987]

You are so inspirational kepp going never give up you dreams

[@aryamanpillai9106]

Many people might have actually thought of this whole pouring something … but this actually proved that it actually happens… salute to you man

[@juliaconte885]

I cant believe I made it here so quick

[@theBoy_69_]

Clap Clap Clap Clap Clap Clap Clap

[@joewebster903]

Well done! Surface tension has many many facets that continue to amaze me after sixty years studying the subject

[@inuka6969]

Imagine peeing on that leaves and ..... (yeah, you can imagine it)

[@blackwall8203]

oh no

[@walikazmi7613]

man

[@bernadettavarley]

Making tea in your bladder.

[@walikazmi7613]

@@bernadettavarley yummy

[@TheAngryCat_]

@@walikazmi7613 delicious

[@agustindellagaspera9706]

Nice video, I just wanted to make one clarification, mate is called to the drink, the green thing is called yerba.

[@vinna2k884]

Some s**** are coming every where to dislike a video..I found one

[@sebaspi]

Haha this is crazy i am from argentina and been following your channel for a year im very happy you talked about mate and even bought yerba lol. Love your content thanks for sharing.

[@bobros2736]

That would seem right... in most cases. Me: Counfusion

[@whitepirate4098]

That's physics lol

[@bobros2736]

Thanks for all the likes

[@TweekLudwig]

I came here to learn and I learned a lot I also got some anxiety and an eerie feeling that nothing is safe from contamination, even though if you pour from a high enough distance, it won't make it to the fresh/uncontaminated body of liquids

[@wolfparty4234]

No joking, I was always told that If I was outside in the woods and I had to go pee, not to pee on poison ivy Bc i could catch it from peeing on it.. I’ve never gotten poison ivy from doing it but now it looks like it could be true!!! Thanks for sharing! Great video!👍🏻👍🏻

[@wolfparty4234]

sujay simha well, that’s probably why I never did get it!! 🤣🤣thanks

[@saqibmudabbar]

Each and every video you make is pure gold

[@Izurak]

I can explain this. With velocity it creates air around it going the opposite direction, if the object is light enough it will join the airflow instead.

[@ProjectPhysX]

Wow! I always learn something new on this channel.

[@lilboy7813]

People who watched BFG: Hey I’ve seen this one. Everyone else: What do you mean you’ve seen it, it’s brand new

[@lasvegascrisis]

im an exterminator and i was always taught about backflow prevention...but im a hands on guy and love to learn visually. you are soo intelligent and interesting, love your videos, and i love learning with the action lab!! thank you!!

[@TheDiamond872]

I've thought of this many times when taking a piss xD

[@NetAndyCz]

Always take piss into a clean toilet;)

[@dawiejoubert2578]

Moron!!!

[@alone-vf4vy]

That was seriously interesting thanks for making this!!!

[@brando3342]

"Nuh uh, not this boy's peentoo, not today." - Dwayne "I don't like guns" Johnson Lol couldn't help myself 😂

[@RandyKing314]

Wow, that's unexpected! Thanks for the vid. Also, when they named that phenomenon, they nailed it.

[@basedurrahman3832]

When ur so early that u just say E in the comment section:

[@promindplayer2468]

Thousands of comments flashed up already

[@matthewsaulsbury3011]

Wow, this is amazing and fascinating! Very well done. It's neat that a student discovered the upstream flow.

[@name_69420]

Come get your "Early Bird Ticket" here...

[@GeorgeTheMonkey166]

No

[@justalexlol_]

yes

[@whitepirate4098]

Nooooooopeeeeeee

[@AshanSanjula]

🙂

[@bluephoenixfox1423]

Can I have mine please

[@estebann]

I did NOT expect to find a refference to my country much less to mate while drinking my own mate. I've seen that happen to my water but always thought the thermos was already "contaminated" with "polvo del mate" (fine dust of the yerba mate)

[@justsomeonewithanezukopfp8224]

I'm not even surprised 2020 is weird

[@Gregory47342]

I am a long time subscriber and I am always amazed at your details and explanation of the experiments which are always so clear. Thank you. Does this affect have anything to do with Salmon going up stream?

[@shamil6687]

So this is why my poop always doesn’t seem to get flushed down completely

[@rayfairbanks6280]

Thank you for making videos like this! I just watched a video suspecting bigfoot of being able to teleport into peoples houses. Its nice to know that science can be as astounding as fantasy, and be equally (if not more), entertaining. Thank you again for making these types of video's. KZbin desperately needs more of this type of content.

[@lolkedsw5239]

This man must be google cause there's no way a human can be that smart

[@SarcasticCupcake223]

I've actually wondered if this was a thing for a while, but I didn't know how to word it to look it up. Good thing I went down this science rabbit hole.

[@ilikebeans3821]

Jesus loves u all so much

[@8BitShadow]

I know I'm late but; it's more like that it was rediscovered. Remember that ooooold tale back when pirates where still a thing about 'rivers running up stream to [the rarest treasures/heaven/godly artifacts/e.c.t]'? We can only assume but it's pretty likely that someone at some point observed this effect at a small scale and extrapolated the thought into "if it can happen here, then it *must* happen on a grander scale somewhere in the ocean!" or something to that affect at least. Still, rediscovering something is just as cool and important as first discovering it.

[@DaveGamesVT]

I gotta make sure I don't piss really close to the surface of things now.

[@kashv1793]

You are the only person whose videos I like before even seeing because I know when it comes to science you are always correct man. Respect you a lot. Thanks for teaching us so much. 👍

[@yashwantherukulla4122]

Wow action lab wow Awsme videos , easy to understand , enjoyable Therefore action lab is the KING of science videos! Thankyou making videos 😊

[@adamosburn754]

It's pressure difference. The higher surface tension has more pressure (so, the water), and the lower surface tension has less pressure (the alcohol) - in general. Think of it this way: the highest pressure in the system is the atmosphere. The particle can only flow from higher pressure to lower pressure, and the next lower pressure would be the water, so you would expect all the particles from both of these to flow into the alcohol, because it has the lowest pressure. BUT, these are under perfect conditions where all forces are constant. They are not constant. When you pour water fast enough, you will notice that small portions/drops break away from the laminar flow. The speed of the water through the air is sufficient to strip a few molecules of water from the column because the pressure of the air over the water increases with speed - motion. Now, when you pour the alcohol next to the water (or the water next to the alcohol), the flow of the fluid increases A.) The air pressure around the flowing fluid and B.) The pressure between the flowing fluid and the resting fluid, so the water and air moving against the alcohol increases the pressure of the air further, locally, and the pressure of the alcohol (relatively, the water is stationary and the alcohol is flowing, and just like flowing air increases the pressure against an air foil, the "flow" of the alcohol increases pressure against the water (which is why water pushes inward but the alcohol pushes outward. The alcohol is still at lower pressure than the atmosphere, but it has a lower point of evaporation, meaning the external surface is gassy enough to create "flow pressure" against the atmosphere on the sides, where it doesn't have as much force against it. This gaseous film also creates that pressure between the water and the alcohol. Pressure, btw, is the amount of force per area, the smaller the area, the more pressure (given the force does not change. Thanks to gravity, it doesn't), so the alcohol has the highest local pressure (because only the first few layers of a fluid matter in an interaction because they are the only ones relatively still, in order to feel the pressure from both sides - meaning that still layer is constantly being pulled up and pushed down on both sides, absorbing the force and creating the balance), but the air has the most pressure from above. So, when you tip the container to pour the water, the air pushes the water out, increasing it's pressure, and it's density carries it to the table. The air, in turn, is pushed aside all around where the fluid is poured, including increasing pressure against the water that is against the table already. This pressure creates a gaseous layer between the air and water. And the same is true of when the second fluid is poured (that is, the alcohol). But the first fluid loses that "amped evaporation" if its own pressure can meet that of the local atmosphere without compressing (which water will do, but alcohol will not, and it evaporates in the air at room temperature more quickly than water). So, the alcohol, still moving towards the higher pressure (all directions), also creates a higher pressure from evaporation force (even if it immediately condenses after) on its side than the water creates on its own side of this barrier. The result is that the higher pressure flows from the alcohol, so it pushes against the water (if you pay attention, you can see the air doing this to the water also as the surface ripples when the alcohol gets moves near, and the food coloring then moves from the force of that pressure into the thing with the least pressure - the water (even though, per volume at rest, the water actually has the most pressure). And the leaf particle gets caught in this turbulence and has to pick the side with the least pressure, usually - as we see, the water, in this case - but in the case of that film, if the film that balances the pressures intersects the path of a leaf such that the lift created above is greater than the pressure below it acts as an air foil against the current and "flies" up the fluid, unable to overcome the atmospheric pressure, but having enough buoyant force to not be forced into the water, and it ends up flowing upstream. That's my hypothesis, given my perspective on fluid dynamics and pressure, so take it with a grain of salt, but consider it.

[@PuffedMuffin]

Thanks for this video man, learnt something today! Liked and Subscribed.

[@joemag7548]

Reminds me of what Viktor Schauberger pointed out with natural water flow, and how trout swim upstream, even up some waterfalls.

[@jaybingham3711]

I would have liked it if you explored the effect given different particle sizes. Also, was there a bias of the particles being lifted mostly on the underside of the flow?

[@trenboloneacetate1]

Why do people always dislike these amazing videos 🤦

[@abelferquiza1627]

Great, i saw that in the bathroom after release the water when pour comes slower and slower, particles goes up the inclinated wall. The explanation i found is simpler: the volume remain the same and if some gets down other part should go upwards.

[@smeggyhead1]

You should confirm that the effect is eliminated if you break up the surface tension of the source water (add some lipids: washing up liquid)

[@dawnraider0072]

"Washing up liquid" ... aka soap? Lol

[@joe_croupier]

i invented (in my mind) a hydrofoil engine in a river clamped to a bridge, it went up and down like a piston with mechanical switches etc to change the angle of the wing on the up and down motion .... hope this makes sense

[@goldmoney6845]

please stop talking

[@joe_croupier]

@@goldmoney6845 but this is a parallel universe with many unknowns .... anything can happen according to time and other shit .... my mind is mine, i thought what i thought and did it right in someway shape or form .... that been said my inveshon would work right ?

[@koukouzee2923]

This channel never fail to amaze me

[@aniruddhashathwar45]

My teacher and myself and most of my classmates are your subscribers and your fan. We watch your videos often. From India. State Karnataka.

[@amarjotsingh9676]

I also noted that phenomena before but never looked so deep into it...❤️

[@fiegenfiegen]

I think we all will redesign any pouring into contaminated waters to place the spout really high!! Thank you! Most interesting.

[@BenFoilHat]

Great video! Thanks! Very interesting how this works, should be known in the culinary industry. Where’s the alcohol/water experiment?

[@Slider68]

I would argue what is happening is the particles have extreme buoyancy, partially due to the surface tension, and when a particle gets into the slower moving regions of the stream (near the edge but still inside the stream) that the buoyancy overcomes the flow and rises up into the source. I've personally seen this when pouring water into a container that contains large quantities of small, very low density, styrofoam particles. Some 10 years ago I experimented with this and came to the conclusion buoyancy was driving the effect. I believe you will find this only occurs when the particles really want to float, either due to low density or surface tension (or both).

[@ytrew9717]

thank you for the research and all the time you invested sharing this fascinating thing!

[@aleksitjvladica.]

I know this as well but watch it because it's you. You are doing so great job.

[@werguitar]

I think the key is understanding that surface waves in water CAN go upward and bring contaminants with it, but just when the flow is subcritical (deep and slow). It seems that this effect of contamination will not occur if the flow is supercrictical (shallow and fast).

[@lukeharben3040]

Awesome video man!! So informative

[@kmw12870]

Amazing!! It was so fun to learn this. I found some dust in my container but never thought about it. Maybe I could test it too! Thanks a lot!

[@sephirapple7317]

I have often wondered if this could happen, now I know it's actually real! I had always thought it was probably impossible but the question has occurred to me numerous times when I have been pouring liquids. Great to see an answer to this!! Even more interesting to hear the explanation for why it happens due to surface tension difference as well. I love that you are always trying to explain the situation, not just demonstrate things in videos! Knowing why things work is just as fascinating as knowing how they work!

[@CreamusG]

The fact that it works better with chalk makes me believe it has something to do with the lack of turbulence around each particle rather than strictly surface tension. If it works even better with talcum powder or worse with something rough like sand that would support my guess.

[@SpiderSparta56]

Oh man you blow my mind every time. WOW I had no idea. Thanks for teaching me something New

[@Bataling]

I used to think this happened when I was younger, and it does. Well that's terrifying

[@Tatertot_Tommy]

In your example with the styrofoam beads, the reason the beads allocate to that particular part of the water is not because of surface tension. It's because the beads are so much lighter than the water that they are simply floating to the highest part of the water. And because the body of water has a crown, the beads will float to the highest part of the crown.

[@loganmosling3314]

I actually used to think about this without actually knowing it was a thing. I always wondered if things could flow up a stream of consistent waterflow. Im so smart

[@juano3000]

At min 4:30 this occurs because there is a full stream. Within the stream is a turbulent flow, swirling (you can see the particles spinning around the stream below the water). These whirlwinds can stretch throughout the entire stream, and bring up small particles and plenty other molecules.

[@juano3000]

Nothing to do with marangoni effect.

[@juano3000]

You should be able to reproduce this with a longer solid stream, and you'll see how the particles swirl up.

[@Kuichio]

It would seem in your example that laminar flow is also at play, but I would also look at how smooth the transition is from flowing midair to the water surface. It looks like it almost isn't moving at that point, but we assume it must be. Perhaps the is some resistance to flow on the outside where the current is weakest, possibly due to some friction or bunching action on impact with the water in front of its motion. In this way the flow there might be slower on the surface.

[@archangel9382]

i am glad that an Argentinian physics student figured this out, my country has contributed

[@ISupportCannabis]

as a kid i always thought every bacteria or “germ” flew upstream so i would be scared to waterfall peoples drink

[@u2bAriel]

A similar effect was actually discussed in the Talmud, where they considered upstream flow of thick liquids, and also the effect of different temperature of the liquid containers on this upstream flow