The bizarre patterns that emerge when you heat ANY fluid
ฝัง
- เผยแพร่เมื่อ 15 ก.พ. 2024
- Click this link hensonshaving.com/stevemould and use the code
stevemould to receive 100 free blades with the purchase of your AL13 razor
Are convection diagrams accurate? I built one to find out.
Paper about solutal convection: www.sciencedirect.com/science...
You can buy my books here:
stevemould.com/books
You can support me on Patreon and get access to the exclusive Discord:
/ stevemould
just like these amazing people:
Alex Hackman
Glenn Sugden
Tj Steyn
Pavel Dubov
Lizzy and Jack
Jeremy Cole
Brendan Williams
Frank Hereford
Lukas Biewald
Damien Szerszinski
Marshall Fitzpatrick
Heather Liu
Grant Hay
John Zelinka
Paul Warelis
Nathan Blubaugh
Twitter: / moulds
Instagram: / stevemouldscience
Facebook: / stevemouldscience
Buy nerdy maths things: mathsgear.co.uk - วิทยาศาสตร์และเทคโนโลยี
I didn’t really talk about the effect the sides of the container has. There must be a boundary layer effect there and that’s likely going to increase turbulent flow.
The Sponsor is Henson Shaving: Click this link hensonshaving.com/stevemould and use the code stevemould to receive 100 free blades with the purchase of your AL13 razor
The obvious answer is you just need to make an infinitely wide container. :)
@@TheMattThompson Ah yes, truly a response a physicist would love, along with those friction-less vacuums of course!
I might have my high school engineering students play around with this question!
There’s definitely an opportunity to go into detail about stratification and it’s effects as a fluid flows.
@@cact0s_ulion405 Consider a spherical cow...
"Ink is expensive"
*Prints a checkerboard
he had to use the rest of the ink before HP bricks his printer for being mildly critical of the price
LOL@@ZaneEckols
The cartridge model between printer and shaver ain't so different. Sponsor's make a difference.
"one problem with the beads is that, they're really expensive."
...
"i bought the expensive beads... i bought them."
@@contrapoetra Hope he recovered them from the water rather than just flushing the lot down the drain.
5:00
The Printer ink reference is pure gold
Probably quite a bit better than pure gold at current prices...
Not only the reference but printer ink is pure gold
An HP printer to be precise
Yeah, i have one and believe me. I wud rather buy a new printer than the ink@@Ahmed_Amine
HP ink is second in price only the Apple storage prices, and both are way more expensive than gold on per weight basis
My dissertation focused on Rayleigh-Bénard convection, I observed by placing a thin layer of oil between two glass layers-one heated and the other cooled. (need large(ish) constant temperature gradient) This setup, resembling a manifold, was heated from below and cooled from above. The entire assembly was then positioned on an adapted overhead projector to magnify the convection cells onto a screen. This allowed for a clear visualisation of the hexagonal patterns that formed.
The topic has broad applications, even in the potential role of these convection cells in concentrating the chemicals necessary for life, suggesting a mechanism by which life's building blocks could be held in place long enough for life to emerge. the cells were quite stable and how matter was contained within them.
If you have a video of this I would love to see this. The hexagonal pattern that forms has got me curious. It seems like this is the effect that is seen on the top of Saturn.
Is this phenomenon understood mathematically?
5:10 Those fluorescent particles were so worth it. Also those Rayleigh-Benard convections look so satisfying! Nice video!
I want a lava lamp like that.
Taking a very long exposure shot with the green particles might result in an interesting photo
Please do!!
What do you call a river made entirely from chocolate and sweets?
A confection current
Rio Oompa Loompa.
BOOOO
THERES THE DOOR
angry upvote
Happy Downvote.
middle midvote
I'm always so Stoked for Fluid Dynamics!
I've Navier heard such a good pun!
😅
That‘s what she said!
wow the whole world really cares! we needed to know that!!!!!!!
lol get over yourself ego andy, this isnt your world.
do not watch this on shrooms
Why not seems fun
ok roman thanks
Don’t tell me what to do
Watch this on shrooms. Got it thanks :)
I absolutely know what you mean by "2D-Version", but in this case it's very important to mention that this process would actually look and work differently in true 2D. This is, from a fluid dynamics standpoint, still 3D. Actual 2D fluid dynamics (which does not exist but is and has been studied mathematically and numerically) works surprisingly different than real-world 3D fluid dynamics.
I'm a PhD student working on turbulence and turbulence modelling, and the difference there between 2D and 3D is astronomically, much of the physics basically flips around. Fascinating stuff! Great video as always!
This is in general the case, dimensionality has a huuuge effect on the dynamics of a system. A 2d vs 3d system can show completely different critical behaviour and phase transitions for instance, like the Kosterlitz-Thouless transition, if you do the calcumations in 3d it is a qualitatively different system. Same goes for 2d vs 3d magnetic systems
can someone explain the differences and maybe why they are so different. mentally it feels as if it shouldn't change that much.
To anyone studying 2D fluid dynamics: you are awesome and I like your strange brain
@@conrrr The "easiest" to understand or at least visualise is vortex stretching. When a vortex spins, conservation of (rotational) momentum and friction are working against each other. In three dimensions, this leads to so-called vortex stretching, where the vortex stretches outside the "swirl-plane" along its rotation axis (vorticity vector).
However, in 2D there is no third dimension for the vortex to stretch "into". But angular momentum and friction are still working against each other.
This leads to completely different physics behaviour. Where 3D vortexes break up into smaller and smaller structures, while in 2D, the opposite happens.
@@mattias2576 Good point!
Miso soup! You can see the convection cells in hot miso soup!
It also tastes much better than Mica.
@@VindolinI think I have to cast my vote for the mica soup actually.
i sometimes see it when i brew tea under a downlighter, in the caustics of the light hitting the bottom of the glass. Must be the heat haze.
Fighting in the dojo!
Miso is also significantly cheaper by weight than gold.
It took me almost 30 seconds to realize that you just shifted to the sponsorship part. Bravo.
For real though 😂 smooth is an understatement
I love that you share so many things that didn't work, those little bits really help reinforce my understanding of various concepts. Always love and look forward to new posts!
Honestly, that HP ink joke at 5:00 is the pinnacle of humour CHANGE MY MIND
I busted out laughing in my breakroom omg so funny
This is the comment I came here for.
100% came straight to the comments for this.
Similar joke in Goldmember where he tries to say pure gold is the most valuable substance and they start talking about caviar. :)
Paused at 5:00, purely to find these comments, and see who else is being exploited by Big Ink.
Steve lives in a 2D world ❤
Flatland!
@@STEAMerBear I love flatland. Wish I could live there 😪😪
is he our friend in a 2d world :0
Somebody introduce him to terraria
OMG HE'S FLAT STEVELY!!
(Flat Stanley's cooler older brother)
obsessed with how the 2d single source convection current moves like a top-down view of a rip current while the Rayleigh-Bénard convection moves like mini tectonic plates lol these examples really highlight just how often we see patterns like this everywhere
Its so facinating how you can see the same patterns all over the world and universe. Like this effect looking exactly like the skin of a croc. Or a walnut looking like a brain. Or the shell of a sea creature looking like a spiraling galaxy. The whole universe is a repeating fractal.
Fun with Large-Scale Convection: Those of us who fly gliders/sailplanes use convective plumes ("thermals") to climb thousands of feet and fly hundreds of miles/KMs without any engine! A typical "thermal" (a single plume of convection) is maybe 50-150 meters across and often exhibits the behavior shown in your very first demonstration at 2:20 : we see wide-spread gently-sinking air on the outskirts of thermals, and lots of turbulence / shear at the interface between the rising and sinking air that descends around the "core" of the thermal. Its quite a thrill to be rising up at several meters per second (i.e. several hundred feet per minute) with no visible energy source. Imagine rising up the height of the Empire State Building in 3 minutes, or the Shard (in London) in 2 minutes - with just the feeling of the air around you, bubbling/pushing up underneath your seat!
That's so fast! So cool!
Damn that's cool. So do you just plop down a hundred miles away with nothing but your glider and your wits?? Lol or are the flights more controlled?
I'm kidding. I've been in ONE glider, when I got my aviation merit badge at summer camp. Only cool camps have airfields.
@supersonictumbleweed @@joshyoung1440 The best way to think of soaring is that its "the world's biggest game of hop-scotch": we'll find a thermal and climb - depending on the strength and height of the convection layer this can be anywhere from 500m - 3000m (1500 ft to 9000+ ft), then glide 10-30km (5-20 miles) while slowly descending. We then find the next bit of lift and repeat the process. When gliding we'll fly anywhere from 90 - 190kph (55 - 120mph). Figuring out where the lift is and how best to make multiple "hops" turns every flight into a bit of a mental puzzle; and since the weather is always changing no two flights are ever the same! We have all of the same controls as any small airplane (aileron, rudder, elevator), just no engine (hey, there's less to break, and no fuel to catch on fire)! 🙂
I know you were kidding, but sometimes we DO have to land without making it back home. We can land at airports or in farm-fields. The French call this going "aux Vaches" - translated to "with the cows". 😀Getting the sailplane out of the field and back home is its own adventure, but modern sailplanes have wings that come off after removing just two big metal pins/bolts. So we can disassemble them in about 30 minutes tow them in long narrow trailers behind our cars.
@@joshyoung1440 Damn I'm jealous, never been to a camp with an airfield.
This takes me back.
2:00 The flakes align with each other locally because they align with the shear flow of the fluid.
7:16 You'll get more regular convection patterns with uniform heating, near the onset of convection, and if you can keep those conditions stable for long enough to reach a steady state. The temperature difference for the onset of convection will depend on the layer depth, viscosity, and thermal properties of your fluids, which is why you got more uniform behavior with the thinner layers and more viscous fluids.
Thank you for your explanation. I was looking for them in the comments. You mentioned "this takes me back". Were you a fluid dynamicist?
@@lucas29476Maybe he's a fluid
@@lucas29476 In grad school, my research was in bilayer convection. With two layers, you can have either thermal coupling or mechanical coupling dominate the interaction between the layers. They tend to drive the flow in the driven layer in opposite directions, so when the effects are of comparable strength you can get oscillations and other interesting time-dependent behaviors near onset. I've since moved on professionally to software engineering, but I still love physics and pattern formation.
Aligning with shear flow sounds deceptively simple, it makes sense but it doesn’t quite explain why it feels relatively unique to mica. So maybe it’s not that unique? Steve kinda presented it like it was but I believe a lot of glittery shaped objects do that. Maybe it’s just the shape then and of course density to some degree I’d assume you’d want stuff closer to water’s density. Is that mostly the case?
@@monhi64 They're not unlike feathers or arrowheads in the rough shape. Flat and longer than they're wide.
Unlike feathers though... They're heavy. They're hard to push around (while much easier to rotate). It's hard to relate to anything because we're used to moving around in air. But imagine maybe a diver's harpoon? A usually metal and heavy spear which has to be heavy underwater to work like wooden spears out of the water do.
I bought a Henson because of your videos. I never gave safety razors much of a thought and just defaulted to the cartridge razors because what else do you do? But the idea that I could just buy the cheapo razors (which my family already buys anyway for purposes other than shaving so I don't have to go out of my way at all) and have a handle and holder for them that lasts a lifetime? Man. Money money money. And it comes in copper, which was my favorite color as a child! And it's still up there on the god-tier colors list for me. So of course I bought one.
I opted for a Henson rather than a regular/cheaper safety razor because it just made more sense to me to have the blade supported in the way they describe it on their website, as well as the wide open channels for rinsing just called to me so much. It hasn't been delivered yet, but I feel very very old and adult-y being excited for a shaving razor of all things to arrive. Child me would be so disappointed.
I bought one and have been using it for about a year. In my opinion it shaves with a single blade every bit as good as my previous 4 blade razor cartridge. If you get the 100 blade box with your order (it comes with a 5 blade box if you just get the safety razor), you could shave every day, replace the blade every week, and not need to buy more blades for 2 years.
advertisement comment
@@BoliceOccifer
"advertisement comment"
And you evidence to back up that claim is what, exactly?
I can not speak to the other comment before mine, but mine was made because I am in my 60s and started out with just this type of razor to shave with and eventually went to the cartridge type when the safety razor I had since I was a teenager wore out.
My main purpose in getting the Henson safety razor was to save money in the long run and also it looked like it would last a lot longer than my first one.
While replacing the blade is not as convenient as it was with my original safety razor, I have been very pleased with how well it works. So my comment was not for advertisement purposes but was made as a satisfied customer who wanted others to know how good this safety razor works.
Perhaps you should not project your motivations onto others.
Thank you for sharing about convection cells! I got those patterns when I heated my agar plates. Left them in place when they solidified.
Steve, 6:00 into this video: 'It happens on the surface of the sun, so I made a 2D model of that at home. It took a couple of goes to create fusion in a sustainable way; I'll post a video about that on my second channel, in case anyone can think of another use for that. Unfortunately, beads that don't melt in the plasma were really expensive, but I bought them anyhow…'
lol-ed
Yes, the sun is liquid, is no a gas.
@@BienestarMutuoBoth liquids and gasses are called fluids, and convection cells occur in both. In this instance the actual fluid that makes up stellar convection cells is a plasma. Pretty interesting stuff honestly, I got distracted and spent maybe 15 minutes reading about solar granules writing this comment.
@@joeyl6963 you have seen how the sun flares fall over?
@@BienestarMutuo The sun is a miasma of incandescent plasma. The sun's not simply made out of gas, no no no.
I learned this from some people who might be giants.
Should do this with a thermal imaging camera as well to see how the actual heat spreads out to the whole thing not just the current of the water
Was thinking the exact same!
That's a hard experiment. They can't see through polycarbonate or borosilicate glass, he'd have to make the sides out of monocrystalline germanium or sapphire.
@@Lontracanadensis perhaps the experiment could be laid flat with an open top or something
@@jamie123b That might be interesting with the convection cells. I'd be curious what the centers or edges would show. Depth though wouldn't work, thermal imagers can't see through water either. I'm honestly not sure what if any liquids would work. Material properties in thermal imaging can be odd. Germanium, a silvery metal, is a clear lens, and I was shocked to find that cheap galvanized steel is a beautiful thermal wavelength mirror. (It was a Jurassic Park "why do we have more animals in there than we have in total?" moment.) Maybe air with some little flakes of something non-flammable and tiny enough to form a fog-like colloid?
Seems to me that there are materials that change colour at different temperatures, liquid or powder form should do it I would think. Wonder if it would cost as much per gramme as the beads?
Your convection cell demo is incredible.
Never thought id be excited about convection cells in a petrie dish. Thanks
I've known about the phenomena in the video for quite some time now, but actually seeing them in an experimental setting like this was really awesome!
As an aeronautical engineer, this is absolutely astounding. These visualizations are so detailed! The way those cells moved in the time lapse was soo so cool. Nice work Steve! Thanks for such an interesting and exciting video!
Just as cool as air tunnels
I think you might find interesting the taylor couette flow experiment (not the high viscosity one, the turbulent flow one). Flow is usually displayed with mica as well.
Now I need to know why the mica flakes tend to align locally.
Same here! There's a paper about composite coatings that seems to suggest shear alignment as a cause?
my guess is that because mica forms very flat very thin layers, the flakes would all have a similar geometry and therefor they tend to align in similar fashion in response to water flows around them
I think he meant to say "they align with the flow" in a way
(because they are flat)
@@nicklanders5178 This was my thought, too. Flakes perpendicular to the direction of flow might be swept along, leaving the ones parallel to it behind slightly. Hard to say if that really works on such a small scale, though.
@@SonOfFurzehattI would imagine the flakes align themselves to all be perpendicular to the flow, each one acting as a little sail
Awesome visual effects with the oil, really interesting to watch. Thank you for sharing
Thanks man, you've taught me much over the years. If you were my teacher throughout all my schooling, there'd be no stopping me.
Great work!
As a paragliding pilot seeing these curls and twists is both interesting and scary at the same time, thinking I'm using the same principle with thermals to stay up in the air.
Huh another paraglider pilot beat me to the comments section with the exact remark I was going to make.
I do hope our Reynolds number is closer to the oil scenario.
It would be interesting to have trigger points at the bottom to see if it works more like thermal triggers.
Paragliding pilot here as well. What I wouldn't give to be able to visualize thermals like this in the air! Seeing the flow along the ground toward the base of the thermal (for lack of a better word here), seeing how the single fast moving thermal was surrounded by a large area of slow moving sink (which makes sense), all very helpful. Thanks!
First time seeing this channel. What a soothing, friendly voice! Smart too!
I also bought a Henson after your last sponsorship and I will never go back. Long time value and pristine quality.
Last time I used a Henson razor, it made me look like a complete muppet. Turns out I got a Jim Henson razor by mistake...
I think I just got to the point with the al13 where I can complete a full shave without having to apply pressure to stop the bleedings.
Single blade shaving is a very different experience. It's like moving from Python to C++.
Sigh. Lol
Must be part of the turbulent flow
@@akaHarvesteR how do you manage to bleed with a safety razor ? Do you have ancient parchment for skin ?
@@Soken50my previous razor was a 1960s Gillette safety razor, probably the pinnacle of that style before the company went to the scam model
I would cut myself with that razor almost every shave.
I have not managed to cut myself on my Henson razor yet.
One thing I noticed that I think is rather cool is that there's occasionally these fast jets of water shooting above the convection currents. You can see this really clearly at 2:10 or so. We tend to think of heating water to be uniform, but a jet of water is water that is superheated and rising very quickly to the top, it slows as it gets to the top as the temperature spreads out. It's fascinating to be shown how we think of water movement in terms of averages, and not every part of the water is perfectly aligned with the average.
I think those are bubbles. Either from boiling or just the flow breaking off bubbles that were stuck to the bottom.
Yeah this was the part I found most interesting. It really does show the statistical/probabilistic nature of reality. Occasionally you will get these exceptionally high energy interactions, but on the average the overall energy level is reasonable. I'd often encounter this as someone who urinates standing up, when occasionally drops of water from the toilet would fly out and go past my head in height. You would think the kinetic energy would at most be able to rise up to it's original height, but the occasional splash in the face would remind you otherwise. (Like how a slow large ball colliding with a smaller one, sends the smaller one away at a much greater speed).
Omg yes I was waiting eagerly for him to talk about/explain it.. I hope he makes a video and talks about this phenomenon more in a future video because it sure seems VERY interesting.
Such a great video nevertheless. Keep up the hard work Steve 💪🏻✌🏻
And I'm surprised how fast seagulls can ascend on rising air currents. Do they 'see' air currents, or fly around randomly until they find one?
@@technobabble_ That makes sense too! I can't really tell from these videos here, but I'm curious what it actually is.
There were so many awesome visualizations in this video. Really cool. Thank you!
This turned out to be far more interesting than I expected. I've seen videos covering the plasma convection cells on the sun, but not on just convection in general. Extremely fascinating when you get into the granular details. Thank you! 😺😻👍
Whenever I see your videos in my recommended I always think it looks interesting but not extremely interesting. Then I watch it and it's always so much more interesting than I thought it would be. The tiny expensive beads are such an excellent demonstration and the demo looks great.
Excellent video as always and really good production value.
Yeah, thumbnails and titles are huge for this reason.
Probably your best video to date. Incredibly complex and fascinating physics presented and explained within an awe-inspiring, insightful, and beautiful cinematographic masterpiece.
I hope you continue this experiment and show us some more patterns.
Great video! Those flow visuals were mesmerizing.
Cream is a complex emulsion / solution of fat and protein in water. The alcohol dissolves the fat and coagulates some proteins , causing changes in density.
I agree. I also believe that evaporation of the alcohol, as he mentions, will also cool the surface quickly, causing it to cool and sink.
I just finished submitting applications to PhD programs in fluid mechanics and I'm currently having a bit of a moment of doubt whether this is what I want to be doing with my career. But seeing this video has reminded me that fluid dynamics really does excite my curiosity. And that really is why I want to do with my life- learn about the things that I'm curious about.
So thank you Steve for making this video and helping me rediscover my excited curiosity.
That retitle hooked me good. Nice job
Great explanation of the concept! I had seen this phenomenon while watching TH-cam woodworkers who use resin, as the heat from the curing resin creates similar convection cell effects. I noticed it occurring over and over but never knew what it was.
What a display of wealth in this video. Printing out a whole checkerboard pattern like that
What is the cheaper way?
@@suatmuradov8608 A grid pattern with decently thick lines would probably do something very similar
@@suatmuradov8608 In Martin Gardner's books black cells were printed as crosshatched IIRC.
The reason he can do it is because you’re watching this video. He’s reinvesting the money he makes from TH-cam into making bigger and better educational videos. Ignore the fiscal aspects of the video and enjoy the science.
Looks like some people missed the subversion of the comment
You need particles for PIV (particle image velocimetry). Usually they are Polyamide particles. There are not so expensive.
The amount of effort you put into these videos is amazing man, and very much appreciated.
These images are mesmerizing... I could keep looking at them all day!
You'd get a kick out of "closed-cell convection" how clouds organize in large stable air-masses.
One trick for the rayleigh-bernard hexagonal cells may be to enlarge the container laterally and get homogeneous temperature in the bottom! These pattern formation systems are quite sensitive to boundary conditions and making the system larger usually helps...
Great video. Thinking about stuff like this is what got me interested in engineering. It’s been a great 35 yr career.
It's fascinating to see convection and its effects so physically displayed. I appreciate your thoughtful and detailed approach. This definitely enhanced my understanding of the concept.
I am lucky to be involved in a research project where 3D convection of warm air in rooms gets simulated and validated by measurements, it's really fascinating!
And I learned of the great importance of window sills if you have straight walls and the heating below your windows like it's often done at least in europe: they break the current and therefore stop the warm air floating upwards from the heating to go along the cold window but redirect it into the room, so the room warms up. I never thought about all of this but when you see it visualised it's immediately obvious.
Steve, for the love of humanity never change! Your content is always an amazing mix of insightful, educational, oddness and amusment!
Absolutely love your videos!
Hey Steve, I'm a long time fan of your videos!
As a follow up and something that might be of interest, those hexagonal patterns reminded me of a trip to the Giant’s Causeway in Northern Ireland. There volcanic activity created that similar honeycomb pattern but frozen it in time as basalt columns.
There are some great geological examples of this around the world. Some nice articles explaining the science too.
Thank you for making this, it gave me a new appreciation for that experience. Cheers sir!
always nice learning something from your channel thanks for the knowledge & entertainment
That is mezmerizing! Thanks for another great visualization of a complex topic!
Simply superb . The best video I’ve ever seen on convection, and you’ve rounded up lots of interesting phenomena I’ve only ever come across individually - in different books. Well done for experiments for making such good visualisations - again far surpassing anything I’ve seen in specialist text books on fluids.
Good timing. I was wondering why the paint in my airbrush was making similar patterns as 6:58, however the paint wasn't being heated, it remained cold the entire time but still made some wild looking patterns. Not sure why it happens with that particular paint, but I could just stare at it and watch it for minutes. It was a very thin, metallic lacquer paint (Alclad Airframe Aluminum). None of the other metallic paints I use do that and there isn't any movement in the paint cup to cause it to happen.. it just happens while stationary, not forcing any air through the airbrush. Maybe the alcohol evaporating? I may record it and upload a video of it.
Great visual demonstrations as always. Also, I bought a Henson last year, and yes it's great and I will never ever go back to cartridge shavers. This is one of those rare products that is actually as good as it's hyped up to be.
You can also see convection cells when heating up a relatively shallow pot of oil on your stove if you have a light shining into it right from above (like the one on your fumehood). The light shining into your pot and being reflected out by the stainless steel bottom appears darker or lighter depending on how it is bent by the changing refraction index of the oil.
It's also quite visible in a frying pan with some oil on the bottom. The "shimmering" surface of the oil is commonly referred to by culinary instructors as a way to know when the pan is hot enough to start cooking.
The shimmering effect is also increased when fish has been fried in it. Especially mackerel. But i think its has different cause.
You can get stable hexagonal cells with ordinary water in a pot. The water in the center of the cells will be a bit higher and the water in the lines between them will be a bit lower. Super easy to see.
(But not easy to create!)
I've found a really excellent convection cell effect in instant miso soup. Literally just heat the soup and let it sit for a few minutes, and it creates really obvious, well defined cells in the floating fish flakes.
Every once in awhile ill come across a video thumbnail recommendation that just nails it for me. This one did. Ive just recently been thinking about and examining this pattern.
Those Rayleigh-Bénard cells were awesome to watch, thank you.
The cells you created with oil and mica looks like a Voronoi pattern, an absolute classic in computational design. Each cell's walls are equidistant from its center point and the center point of its adjointing cells' center points. Also appears in nature with real biological cells.
It's really funny. Space Engine uses a voronoi texture for the surface of stars. And I always thought it was weird but never looked into it. And now after seeing the actual pattern on the surface of a star, I think it was the perfect decision.
To be unnecessarily pedantic, your Tia Maria appears to be Kahlua.
Despite needlessly saying that, I’m keen to say that your expertise are far more impressive and important than my tiny minded pedantry. Your work is mesmerising and always a delightful watch. Thanks Steve!
There is no unnecessary pedantry, only unappreciated.
@@Jablicek good one lol
i immediately recognised those “convection cells” as an example of the voronoi tessellation: the pattern that appears when dry mud cracks, when bubbles connect and on the bodies of giraffes! every straight “wall” of a cell is exactly half way between the origins of the two neighbouring cells, and each wall is perpendicular to the vector drawn from the origin point straight outwards towards the wall.
the origin points are formed from the vertical currents that rise from the base of the dish, which would also explain why the cells change, multiply and divide according to natural chaos. whenever a new current forms so does a new cell, and the neighbouring cells’ sizes and shapes adjust in order to accommodate it. fascinating stuff, and an excellent video!
This has been one of my favorite videos in a while :)
7:10 Wow, hexagons really are the bestagons.
Would something like Schlieren imaging work for visualizing this? I know it's useful for visualizing heat in air, but maybe for water too with the right setup. Also, applying some of your exploration into motion amplification would be interesting to see here. Thanks for the video!
You beat me to it (Schlieren _and_ motion amplification)
Two of the most mindblowing things I've come across, in terms of understanding how something moves
The top view on oil is one of my favourite things to look at while pouring levigated clay! It looks exactly the same! Super cool to finally understand it's the mixing buoyancy layers that are causing it!!
I bought a Henson when you first sponsored it, and it is fantastic! It's literally great for *every* part of the body!
This is the review I needed to make the decision. Thank you.
@SteveMould While buoyancy is indeed what is driving the convection currents, I find it more useful to think about it in terms of pressure differences, as that allows you to visualize the actual forces involved.
For a simple example, imagine you heat a thin column of liquid within a container of that liquid. The pressure within that and neighboring columns is given by *pgh*
But if you heat the bottom of one of the columns, its density *p* drops and it expands. Because the pressure drop with increasing height is now slower, *dP/dh=pg* is smaller, it means the pressure along the entire length of the heated column is now greater than everywhere else in the liquid. This means there's a net force driving liquid away from the column and it now weighs less. Another way to think about it is the expanded top of the column has to even out with the rest of the liquid. Either way, you now have less pressure at the bottom of column, and it now will be pushed up by the pressure from the rest of the liquid.
For simulating grondwater flow I used liquid, clear soap (hand soap), whipped it up so there were many bubbles inside. It worked rather well, the larger bubbels quickly rose to the surface, the tiny ones remained long enough (hours!) and made visualisation possible. For almost no costs. But I loved the materials you used, it looked great👍
My best guess for why mica flakes line up locally is that similar conditions result in similar alignment. The direction and speed of flow is going to be similar locally so the particles line up with that, and therefore each other.
This video answered a question I've had for MONTHS now. I work in a restaurant and it is often my job to scrub down the flat top at close. to start, you pour oil on it, and when you do that, those little spots appear, I've always thought they were mesmerizing, but I didn't know why they form and I didn't get a satisfactory answer by looking it up online, but now I know! thanks!
The footage around 6:55 is mesmerizing. Love it!
I have some golden powder paint (ingredients unknown), when i mix it with turpentine or some other paint thinner, on a saucer, it creates the convection cells you were talking about!!!
I love how he's unaware that the comments on his sponsored video were clearly bots 😂
Im glad your channel exploded this way in the past few years wow
7:05 was exceptionally beautiful, cheers!
It just keeps getting better!!! *Violently Explodes*
Steve, you can get a similar pattern to that of the sun by using a thermal camera and looking at a bowl of cooling soup, preferably something with medium viscosity. I chanced upon it when looking at how fast my corn potage was cooling down lol!
I can’t think of the amount of work behind this video. Must be massive.
I think the flakes align locally because they all interact the local liquid nearby, They are also all responding to the movement within the liquid. Because they are more massive than water molecules, the flakes have a lot more momentum and this would resist the influence of the forces trying to move it.They also collide with each other more when they are mostly parallel to each other. Whereas when one is edgewise to another's face they are less likely to strike each other. Combine these two effects and there is a combing process which aligns the flakes. They share momentum when they strike each other, effecting syncing the two flakes up. As more and more align the effect is more and more visible. The more organized flakes still respond to significant forces within the liquid, which is why it works so well to show the convection currents in the video.
i like to think of the flakes acting like miniature weathervanes
I think that the mica powder locally aligns not because they interact with each other in some way. But because they are probably not perfect spheres (maybe discs or needles) so they align with the direction of the current in the water. Because the current is locally in the same direction the mica powder aligns locally. And in some directions the mica powder probably reflects more or less light giving the different shade’s of colour.
Hmm, would they align with the flow direction?
What if rather than aligning with the flow velocity, they align based on changes in the flow velocity across space?
Like, if the component of the fluid flow direction perpendicular to the surface of the flake, is greater on one side of the flake than on the other, it seems to me like that would cause it to rotate.
(I would expect such rates of change over space of flow velocity, would be similar in nearby locations.)
Idk, just an idea.
@@drdca8263I think your idea is better. I was just speculating why they would align.
@@hallohoegaathet7182 well, I wouldn’t have had the idea I had if I hadn’t seen your comment,
I was really just trying to (potentially) refine the idea you already presented
My conjecture on why the mica poweder is rheoscopic is the powder is tiny reflective sheets, and they arnt really aligning. If they are in a shear force of fluid, they will roll, and they can only really roll in 2 meaningful ways. They can spin normal to their plane like a frisbee or perpendicular to normal of their plane, like a paddlewheel.
Thus in a shear force, at least 50% of the mica powder is rolling like paddle wheels with their axis aligned with the shear force. They are all in a randomized state, but at least that axis is lined up and the lined up pieces act like a uniform mirror when viewed at the correct lighting and angle.
I have seen these patterns in high speed welding videos. Welding as an industrial progress got analyzed by quite a few people and some have done very neat slow motion videos.
I wonder how pressure or a vacuum in the air gap would affect the motion of the liquid, even a oil layer retarding the motion until it heats up and becomes thinner.
I'm glad I stumbled across this channel, another inquisitive subscriber added.
Loved the HP plug. LMAO!!
great timing
Cool, or hot, or somewhere in between! It's all a bit odd, but I'm always glad I watch your vids.
I remember watching a school's video that showed the hexagonal cells in a fluid heated from below. I think it was made in the Cavendish Labs but well done for getting yours as close. I also like to watch the Langmuir circulation cells that form on the sea’s surface, but you’d need a big Petri dish to re-create these.
Finally, there’s a character in ‘King Solomon's Mines’ by Rider Haggard who has to shave half his face due to being caught as so. It took me a while to notice this on you!
6:45 I always saw this in oil in a deep fryer.
The effect was noticeable because of the oil viscosity and how the flow made the oil surface (bumpy) and how the heat distorted the image of the heating element and a plate that had circular holes that was on it.
And after prolonged use small fries crumbs made it more visible
You can also use Sodium polytungstate (high density very soluble salt) to increase the density of water up to 3.6g/ml or so. Not dirt cheap but not gold either. Even makes aluminum float…
7:22 it triggers my trypophobia
This episode makes me so happy. I wish you'd make more videos about fluid dynamics, especially on cymatics. I've done so many experiments at home and they are so fascinating. PLEASE! I'll send you some videos of my experiments if you like? I want to know what happens. I've asked sooo many teachers here in sweden and they can't explain it. It's just magical!
Impressive content!! All love from Brazil ❤
A thing I like about this channel is the quality of the sponsors. I decided to give a try to Henson's razor, and I don't regret it after a year or so. What I love about is how basic it is, one blade, no moving parts, no electricity. But it's made perfectly. For people coming back from electrical razors as myself you should expect some small cuts the first couple of times, but once used to it (right angle, right pressure), I can not go back.
LoL same thing, once you go Henson you don't go back son 😮
I bought 2 of em : the al13 and the al13m 💪💪
And should anyone want to deprive me of them, they'll have to pry them from my cold dead hands 🤘🧐🤘
beep boop
Flew hang gliders for many years searching desperately for this stuff. The turbulent, sinking air around the rising column made things all the more interesting - and it could all be happening a few feet from rocks and trees.
You can attach a hang glider to a trike with a small engine (like a rotax 447) on it and you won't have to search for thermals anymore. :)
@@LiftPizzas Flying mountain thermals in a hang glider is euphoric. No experience in life ever came close. Plus you build a knowledge of the air that powered pilots never achieve.
You make me laugh so much Steve. I really appreciate you, your intellect, and your humor. I’ve always had a love for Rayleigh-Bénard Convection pattern, as it captures my mind with its beautiful maths.
Thermodynamics and Particle Physics are super duper together. Great shots. Would love to see some with a crazier macro lens or something.
Also very interesting how the Mica flakes orient themselves locally. I'd like to learn more about currents in liquid against flat slates. We need to zoom in and slow down.