The Levitating Liquid Pendulum

[@SteveMould]

A big thank you to Benjamin Apffel, Filip Novkoski, Antonin Eddi and Emmanuel Fort for giving me their experimental footage. Hope you all enjoyed the video!

[@InvadersDie]

I did enjoy the video, but now I'm scared of floating down to the bottom of wave pools

[@choiceschoices5910]

SERIOUS QUESTION: Could This Effect Be Used To Stabilize Planes Flying Around Or Faster Than The Speed Of Sound (Sound Barrier) ??? (Alternatively Could Active SonicBoom Noise Canceling Be Possible ???)

[@Scott_C]

When I first read the title I thought this was going to move in the "sono-levitation" direction where water droplets are held in air with ultrasonic levitation. Which this kind of is... Very slow "ultrasonic" sound movements. Using the walls of the container as the friction point instead of atmosphere and and high frequency sound.

[@christopherj3367]

If I'm not mistaken I think this is the concept on how they are trying to make tall skyscrapers earth quake proof.

[@choiceschoices5910]

@@christopherj3367 You do realize the amount of energy it would take to keep such a building in motion? (also imagine what happens when there is a power outage, domino towers anyone?)

[@Fraxxxi]

Finally. I've always wanted to levitate some silicone oil but was never quite sure how to achieve it.

[@3693G]

HAHAHAHAHAHAHAHAHAHA UPVOTED

[@lukegrigorian3192]

Exactly 😁

[@pvic6959]

... do i want to know why

[@yee9072]

Right?me too

[@CynHicks]

I've been dreaming about this since I was a kid!

[@John_C_J]

"Inverted buoyancy" is definitely a high school project winner. Looks so simple, yet so unreal.

[@rawnukles]

and tomorrow negative energy for the school science project warp drive engine

[@ObscuriaDragunAed]

I know when I judged a high school science fair that student would've won top marks from me. So much more creative than the typical vinegar and baking soda Volcano thing that people keep putting in science fairs. Granted, the dude that had the volcano still got top marks from me because of their showmanship and the fact that they actually knew why volcanoes erupt.

[@mrwess1927]

@@ObscuriaDragunAed whatever it takes to encourage learning.

[@sylvrwolflol]

My science fair project was trying to see if holmium affects the measurable qualities of a superconductor. Unfortunately it failed due to a lack of properly prepared holmium to run the process, but still one of the coolest nerd things I've done. I'm absolutely here for this kind of funky science fair project

[@thepoppunx]

i really wish some flat earther can see this...

[@PJoriginal]

"It makes no sense until you think about it for a bit. And then it makes sense again. And then you think about it a bit more, then it stops making sense. And then you think about it even more, and then it makes sense again" This applies to a lot of things in life and life in general lol

[@97ynoT91]

That makes no sense...

[@97ynoT91]

Well, come to think of it...

[@columbus8myhw]

This is why we have equations. They give the final verdict Well, no, experiment is the final verdict

[@DABATTLESUIT]

Is this dialectics?

[@Andytlp]

Were not perfect beings. Most people forget simplest of things. Memory retention is hard. Holding shape for matter types must be too :D

[@rubeningels5060]

This upside down buoyancy is the most incredibly interesting thing I have seen in a long time!

[@U014B]

Ohhh, so _that's_ why Australian boats don't fall off the Earth.

[@luckystar3641]

Wait does this mean Australia is just constantly vibrating? They must get a lot of upside down earthquakes.

[@roidroid]

Lol Tinney goes brrrrrr

[@robertkesselring]

@@luckystar3641 A whole continent full of hopping kangaroos will do that.

[@2blocksonthewall4253]

All of this is gold

[@dangerouspie0319]

God is a burley Swedish man who belts out a 120hz yodel from the center of the Earth to allow Australians to exist.

[@BenHanson137]

That visual aid at 8:58 was perfect, really connected the concept of 'accelerating downwards = negative g's = smoother surface' to my intuitive understanding of how I imagine things would work

[@deathhound9400]

its like hitting (or shaking) a bottle of viscous liquid (jam, ketchup, etc), that has an uneven surface, on the table. it smoothes out

[@federicoaguilar7610]

9:50 but in the end, the making sense of the problem averages out until there is a stable making of sense.

[@Anton-cv2ti]

Shaking the head in a stable frequency helps

[@NicolaiSyvertsen]

@@Anton-cv2ti Synchronized nodding of heads

[@hungryanimal5112]

Amazing! This reminds me of something else... This stabilising effect of a vibration to a vertical structure can also be illustrated in five storey pagodas common in Japan. The topmost spire or sorin consists of a shaft on which floating rings are attached near its base which springs from the roof. This shaft runs along the entire core of the tower and is free floating. On an event of an earthquake, the rings jiggle vigorously, stabilizing the shaft. This , together with the manner of construction of the tower, ie wood joinery, are believed to contribute to the overall seismic resilience of the structure. These pagodas are vaunted to have survived severe earthquakes.

[@JevinJohnson-CloudShift]

"Dear, why is honey and 120 Hz Vibration generator on the shopping list?"

[@imveryangryitsnotbutter]

She's going to be so disappointed when she finds out you're not planning to use them on her.

[@vatanrangani8033]

Sounds kinky

[@rab3ar]

It's the recipe for a yeast infection

[@cezarcatalin1406]

Vatan Rangani That’s how we can fuck gravity.

[@xponen]

@@cezarcatalin1406 it's just a trick, the air pocket underneath the honey is pushing the honey upward, and the honey is soo viscous that when you vibrate them it settle to a flat & flatter form that seal the bubble from escaping. When you stop vibrating it, the honey start bending and break a hole that let the compressed air thru and the honey fall.

[@BricktowneMedia]

Dude, great work in the edit, that voice over of 'Liquid' when you say 'water' is seamless! Even got the tamber on point. Well done!

[@qfz2112]

8:40 You originally said "body of water", didn't you. I almost didn't notice the overdub, that was really well done.

[@SteveMould]

Well spotted!

[@georgplaz]

@@SteveMould that explains it! i thought video and audio were out of sync, but weirdly just briefly and none of the two seemed to be slowed.

[@Mernom]

Would a sufficiently high vibration frequency allow for water levitation?

[@ericl8743]

@@Mernom yes. It'll work with anything

[@cursh6898]

I thought I heard water during that part. That was because of his lips' movement, I think. My brain is playing games on me. Well spotted.

[@lucmar6867]

This was a really good video, this is a marvelous effect I never knew existed and it goes completely against my intuition. The video explained everything very well and in a simplistic manner, and I found it genuinely entertaining to watch. Thank you!

[@nikanj]

I love the little boat the put in there. I'm just imagining an excerpt from their paper on this effect. "Compared to a liquid at rest, the analogue navel vessel (ANV) displaces..."

[@finn596]

"Ok so we need a object to show how the water displaces" "Hnnnggg boat"

[@iplay9s]

Saw the title and thumbnail but passed on the video cause I never get any good info out of these kind and it's a waste of time, but then as I scrolled I saw it was Mould and raced back to watch it cause I can trust the quality in your work

[@scientificconsideration8294]

The "Inverted Buoyancy" part of this should probably be mentioned in the title. I would watch a whole video only about that!

[@edwardlane1255]

I wanted the scientists to deliberately "sink" the upside down boat (with a stick or something) - to find out if it would automatically flip when it got to the real surface

[@tlqy]

Sadly I think he could do a better job at explaining it. It is actually a stable equilibrium. Buoyancy isn't really applicable here. You have to dig further. Where does buoyancy come from? It comes from the different levels of pressure at different depths. Most of the time this pressure difference is caused through gravity: when there's a greater amount of water above it this will create more pressure. Next: how does pressure work? Pressure applies uniformly in all directions. So the buoyancy is created through a larger pressure underneath the object than above, so if you subtract the force pushing downwards from the force pushing upwards you will still get a resulting upwards force: buoyancy! But now the question is, how is the pressure in the liquid. I would presume that it's the lowest on the top and the bottom, and the maximum is somewhere in between in the lower half. So if you have something in the lower half it will experience a buoyancy downwards because the pressure over it is greater than under it. But then it starts to get interesting if you look at the air underneath it. This air also has a higher pressure...

[@IHateUniqueUsernames]

@@edwardlane1255 I think, hypothetically, this depends less on the topic (i.e. the equilibrium between material of different density) and more to do with the design of the boat itself. We do have capsize resistant boats that will right itself after being flipped over; most boats don't once past its tipping point. Basically, this setup creates an isolated self-contained system that somewhat negates gravity; so much so we can assume no gravity when thinking within the confined boundary of this system. So, assuming the boat used has this self-fighting property, the vibration motion becomes the major contributing force to the boat's definition of "up" (relative to the fluid it should be buoyant in), compared to Earth's gravity. If you push the inverted boat beyond the middle point of the fluid it should be buoyant on, it will "identify" a new "up" (one that aligns with our experience); flip upright, and wave a nice hello to its little friend at the top. Extension: I think, if you push the top boat into the fluid, pass the middle point, it should self-right and end up floating inverted (it should not fall through the less dense air below because gravity as we experience it plays a smaller role in this contained environment; and what is practical gravity in this purpose?). The vibration is providing sufficient force to counterintuitively push the bottom boat, keeping it on the border between materials. It would probably depend on the frequency of the vibration relative to gravity; the closer it is, the easier it is to go pass the dividing line where the force maintains equilibrium. It would be fun to know how my uneducated guess is wrong.

[@mattcarter1797]

@@tlqy , you've asked some great questions! The presence of vibrations does not change the fact that average pressure increases going downward (due to the gravity). Buoyancy is, indeed, a consequence of pressure integrated across the entire surface area. Average pressure at the top of the liquid is 1 atm. Going deeper (downward) into the liquid, the average pressure increases steadily. Exiting the bottom of the liquid and continuing downward, average pressure continues to increase, but not significantly (since air is low density). (I say "average pressure" because it actually fluctuates throughout each vibration wave: As the whole system is accelerated downward on half of the vibration wave, the fluid pressures in the container flip so that the maximum pressure is at the top of the container and the minimum pressure is at the bottom.) @SteveMould explained it correctly: If you were to "submerge" the inverted buoyant boat upward into the liquid, the average pressure on the upper surface would be less than the average pressure on the lower surface, thereby forcing the boat upward (traditional buoyancy). What's keeping the boat stable in the inverted position under the liquid is the same mechanism that keeps the liquid surface level: the vibration. If the inverted boat is slightly displaced upward (into the liquid), the vibrations will correct this by pushing harder upward on the surrounding liquid. Likewise, if the inverted boat is slightly displaced downward (away from the liquid), the vibrations will correct this by pushing harder upward on the inverted boat. If the boat is pushed too far downward (away from the liquid), it will be in the air and will fall down as usual. So, the boat has 3 stable positions: at the top of the liquid, at the bottom of the liquid, and at the bottom of the air under the liquid. The middle position has only a narrow band of stability.

[@JHA854]

"Here is my vibration generator" Okay, Steve.

[@markm0000]

Steve’s wife: Give that back!

[@Nafinafnaf]

@@markm0000 holup

[@chrisbustos1431]

@@markm0000 😏

[@nulldeathwhat7200]

1:51 Ah! I see the scientist is a man of culture as well.

[@DavidCourtney]

1:40 - "A group of scientists were working on the problem..." It amazes me that someone was sitting around and one day thought, "The fact that honey doesn't levitate in the middle of a jar is a real problem that needs solving."

[@asailijhijr]

Scientists don't start out sitting around and wondering. They start out as doctoral students who need to work on a novel piece of research in order to become scientists.

[@Anton-cv2ti]

Image always taking the first scoop of honey right up until there's nothing left

[@HasanProd]

but that is a problem that needs solving, what if i wanted a jar of levitating honey and i had no one to buy it from. they could sell it to me.

[@andrewsnow7386]

But what if you had a liquid fueled rocket that shakes a lot? It could be very bad if there is no fuel at the bottom of the tank where you are expecting it to be. I'm not saying this particular thing has ever been a problem, but a lack of understanding of strange physical phenomenon -- metal fatigue, rogue waves, soil liquefaction, etc., etc., etc. -- has, and will in all likelihood, continue to kill people.

[@mduckernz]

@@andrewsnow7386 This is actually a significant issue for liquid propellant rockets and its called pogo (as in the stick). The F1 moon rocket had it quite badly due to combustion instability from the engine producing oscillation that caused oscillating fuel flow which only caused the instabilities to become worse until it burned out due to gulping ullage vapour (from the liquid oxygen and kerosene jumping up and down in the tank) - and also caused huge structural stress... these tanks are very thin, and hundreds of tonnes of explosive liquids jumping up and down in thin tanks is a Bad Thing lol It was solved with changing combustion chamber & injector geometry to suppress pressure waves - and installing liquid baffles compressed by helium to hold down the fluids.

[@rajgill7576]

I much enjoyed that jazzy quip while the fluid danced in the very beginning

[@vettechdave]

Enjoyed the video, thank you. One matter which stood out to me was you 'free from gravity' demonstration 0n the table. The effect is exactly how a semi-trailer works when being pulled (driving/turning forward) and being pushed (backing the trailer into a dock/around a corner).

[@deprivedoftrance]

So if you want to straighten out a trailer in a tight spot just move back and forth really fast? Your analogy was actually super helpful!

[@vettechdave]

@@deprivedoftrance well, it does make me wonder if there could be a way to vibrate the kingpin (which connects the trailer to the 5th wheel) to stabilize the trailer as you back it up.

[@pwkoert6594]

@@vettechdave It would probably work on an icy surface but unfortunately not with rubber tires on tarmac/concrete... also the tractor needs to be heavier than the trailer...

[@SolidSiren]

Good analogy!

[@markdoldon8852]

@@vettechdave you'd have to vibrate the entire unit (tractor and trailer), as well as provide frictionless movement sideways (i think). And of course, if vibrating the tractor you run the risk of finding the frequency that TESLA discovered that created violently UNSTABLE bowels....so we might want to use a remote controlled tractor!

[@joelnorton9742]

Excellent parlor trick of science. Reminds me of early electrical and magnetic display pieces presented to explain what is really happening! Love your videos

[@andrewrobotbuilder]

Scientist: Are you stable? Viscous liquid: Well yes, but actually no

[@Beerfazz]

... but actually yes

[@Peter_1986]

*Mathematician:* "let's find the formula for this phenomenon in its most general form."

[@coreyskuse9387]

Me and a viscous fluid have something in common then!

[@ChasenR]

I got to be the 420th like, too bad it wasnt at 4:20. Still an honor.

[@andrewrobotbuilder]

@@ChasenR Congratulations, I'm seeing your 420th like now

[@louis1001]

8:40 That was a flawless audio correction. I'm so impressed. The only way to tell was the missed synced lips, but even then I couldn't believe it. Awesome. The floaty liquid is cool too.

[@Videohead-eq5cy]

Just noticed the same thing

[@FlorianLinscheid]

That honestly creeped me out even more because I couldn't hear anything strange.

[@marian-gabriel9518]

Two things. One .That is nicely done because he actually thinks...what most people do when they record a correction is they only speak that one word which will sound different than it would sound when spoken in a sentence because of phrasal intonation and emphasis. Second. He wanted to cover up the word "water" with the word "liquid" but then at @9:00 he said "water" again :P

[@fowlerj111]

Pretty soon it will be routine to edit the video to match the audio as well - maybe the least ominous application of deep fake

[@mg4695]

It actually looked to me like the inverted boat was covered in a film of oil. In fact, some drops of oil could be seen dripping off the tip of the mast. Could it be that surface tension was playing a role in keeping the inverted boat in position?

[@Scott_C]

9:00 When you're talking about forces at play, I think you're also forgetting atmospheric pressure. The air trapped beneath the silicone is also oscillating up and down at the same rate trapping the liquid additionally. This also would be part of the effect for the upside down boat.

[@T3sl4]

Indeed. Pretty sure the trapped air is pressurized, and opposing the average weight of the liquid. Which keeps the slug of mass suspended. The sidewalls only need to transmit dynamic force (so the shear viscosity needs to be high enough relative to the frequency or amplitude), it's not like friction is holding it up alone. As said in the intro, the liquid doesn't simply fall into the air space below it, rather its surface collapses; if the surface is forced to a stable level (by the vibration), it'll "levitate" quite happily! And we can see quite graphically that the slug of liquid is making a tight seal with the sidewalls; it's pretty rough around the edges, there's a lot of splashing, but the middle is making a continuous seal. If the slug of liquid were thin enough that the splashing breaks through the mass, it would fart out and collapse. Hey, so, corollary: this shouldn't work in vacuum! Liquid could be held in a container until cavitation forms (held by cohesion), but there's no suction or pressure to prevent it from collapsing once a cavity forms. Of course, you need specialized liquids to do that; vacuum grade silicone oil would do.

[@anderpanders6210]

@@T3sl4 there wouldn't be air to levitate on in a vacuum

[@T3sl4]

@@anderpanders6210 I know that's what I said

[@anderpanders6210]

@@T3sl4 This also wouldn't work without a liquid ;) Edit: Maybe with some cohesive gasses and ridiculous vibrations it could work even without a liquid?

[@davidwuhrer6704]

@@anderpanders6210 You could use gasses of different density and viscosity, but it probably wouldn't look as impressive.

[@j7a1k1e]

~~The bottom boat isnt submerged, it's "dommerged"~~ Nevermind I had a think about it. Sub doesn't necessarily imply lower or less in this context. Instead it means that it is inside of or is less of the total. If we think about the boat and the fluid as one body of matter the boat is less of the material than the water is. Thus the boat is in fact submerged in the silicone oil.

[@christian-g]

10:05 "Immersed" or "semi-immersed" might be a suitable alternative for the situation. It evades the up-down connotation of "sub-".

[@feha92]

Finally someone who used an existing word

[@maxritter7868]

Or alternatively you could fully lean into it and call it "upmerged"

[@parmesanzero7678]

You do an amazing job about a explaining things by introducing base concepts that can be understood and then building on those explain the more complicated phenomena.

[@permik]

10:07 "Submerged seems a bit wierd in this context", how about upmerged?

[@georgplaz]

or maybe supermerged?

[@SteveMould]

I like both of these!

[@FernandoJRodriguezFernandoJRM]

Supramerged, to pay respect to Latin prefixes, would be my suggestion.

[@Shadow81989]

damn, I'm one hour late - was about to write exactly that: "upmerged".

[@Beerfazz]

now merge supermerged and upmerged to supmerged and you can confuse everyone

[@MoldySpace]

This is especially fascinating to me for a very different reason, during my astronomy major the most interesting question I ever got was to model a harmonic oscillator of a displaced piston compressing an ideal gas, as a way to think about variable stars. And now here it is in the real!

[@jabekens]

I LOVE this video. A few weeks ago I read the article that you referenced at the beginning, and I couldn't quite wrap my head around it. Your explanation and the scientists' video footage really make this whole concept much clearer. Thanks Steve!!!

[@amoose136]

So glad to finally see an inverted pendulum explanation. After google was no help I showed a video of an inverted pendulum to my freshman level physics professor and he said he’d look into it and then a few months later, I kid you not, he unexpectedly died.

[@WhiterunGuard11998]

Steve "I'll leave a link to it in the description" Mould 😂

[@23Scadu]

It's gonna be a real bummer when KZbin decides we don't need descriptions anymore.

[@user-ym2mp4jh2c]

I have a comparison that may help with the part about the inverted pendulum: Just as a wheel (not the bike frame's speed but the rotating wheel itself) stabilizes better at higher rotational speed due to the gyroscopic effect, 1D vibratory motion (up-down oscillation) acts the same way, stabilizing an inverted pendulum under the effect of gravity. It seems to me the commonly observed gyroscopic effect has the same underlying cause as the inverted pendulum's interesting stabilization. My reasoning is that a quickly-rotating bike wheel operates the same way as a vertically oscillating pendulum in that if you take a single point on a rotating wheel at a certain time, say the topmost point, and then let time pass, the point will proceed to the bottommost point and come back up, just like an oscillating inverted pendulum. Using the logic in your video about each components' vertical and horizontal differences (in acceleration) between the upstroke and downstroke of the pendulum (and in my case, a point on a wheel), your logic should also apply to forces perpendicular to a spinning wheel. That is why I feel that wheels are stable at fast rpm (i.e. keeping the wheel 'vertical' and not falling to the ground when the wheel spins quickly). Note: The rotating wheel shouldn't need to have frictional contact with, nor be moving with respect to, the ground - i.e. the wheel doesn't have to touch the ground. Look up 'rotating wingnut in space'.

[@wmhilton-old]

Inverted boyancy... "when you think about it, it makes sense" NOPE HE'S A WITCH

[@KiwiNom]

"burn the witch!"

[@namewarvergeben]

It floats. Like a witch!

[@DrD0000M]

@@namewarvergeben Floats upside down, like an Australian witch!

[@Mernom]

But if you think about it some more, it stops making sense.

[@TheAngelsHaveThePhoneBox]

Don't try to understand it, feel it.

[@MichalReska]

This explanation is missing one crucial piece of information - momentum. The simple explanation shown at 7:45 does not suffice, because the "up" and "down" forces are completely symmetrical to one another - changing direction from going up to down is just like changing the time flow and the pendulum would go back to its previous position. The forces provide an angular momentum to the pendulum, which helps to "overshoot" the position it reaches at the "topmost" and "bottommost" points. At the bottom point of the cycle (before going up) its angular momentum pushes the pendulum to even more straight position, which makes the "un-straightening" force when next going up less prominent and therefore the forces acting upon the pendulum not symmetrical to when the pendulum was going down. At the topmost position the angular momentum makes the pendulum go more sideways, which in turn makes the "straightening" force more prominent when it next goes down. This is analogous to the honey considering the liquids momentum.

[@dle511]

“If you want to find the secrets of the universe, think in terms of energy, frequency and vibration.” Nikola Tesla anytime you want to "defy" physics try vibrating it really hard, it might just work

[@ChasenR]

If you could vibrate individual atoms in solids, you could cause "spontaneous" combustion. Learned this from a movie, not from school.

[@conditionalbee9603]

Time to buy a thousand vibrators

[@RSAgility]

String theory. Yea.

[@Destroier534]

@@ChasenR There is no need to vibrate them individually, you can just vibrate all of them. Which you can do, with a heat gun (it's like a powerful hair dryer), microwaves, fire, or an electric heating element. Though if you could focus it to just a small(ish) number of atoms, the effect would be localized, but stronger. Which you can do, with lasers. That's how powerful laser pointers can light matches and pop balloons, and industrial lasers can cut metal.

[@matthiashacker4486]

A perfect entrance to a secret base

[@grantfhay]

Awesome! *thinking of applications* I know - I'll hide my valuables in an opaque honey jar underneath a floating layer of honey! No one will think to look under the violently shaking honey jar! Now I just need to devise a bottom hatch that can open and close while the jar is shaking so that I can store and retrieve things without them getting sticky...

[@kingradical-x]

Why have I not seen this channel before? I need to binge these videos next weekend. Fascinating content!

[@christopherconroy2805]

Another great video! I think the fact that this material has friction with the sides of the container the reason why the gravity correlation works in this explanation. I don't think the explanation holds in a frictionless environment, nothing to give a counteracting force for the "flattening" and it is what is allowing the drag on the upward movement.

[@davidwuhrer6704]

I'm sure it would work better in a frictionless environment, as long as cohesion is still a thing.

[@josephgeidel3507]

I went into this video certain I would never understand what was happening but interested in seeing the cool visuals, but the explanation about vibrating pendulums made it so clear I felt my brain grow.

[@pierson9728]

10:07 the word you’re looking for is “supermerged.” i may have made it up but it definitely works here

[@ArnaudMEURET]

Not to be mixed with suppermerged which is when you’re overworked and your head ends up merging into your supper.

[@philipmcbride3900]

I love this awesome explanation! Taking "magic" and making it seem obvious and intuitive! Thank you for this!

[@Terrain239]

1:03 holding jar, hand and camera upside down. Genius

[@rensvanbreukelen3762]

Orrr he's just vibrating his hand with 120Hz frequency

[@yajnavalkiagargi]

I wanna say thank you man and please keep making these videos. I just now found this channel and i LOVE the fact that i get to listen and learn SO DAMN MUCH. Like..... yes. The world needs this lol

[@Anton-cv2ti]

8:38 I thought my eyes were temporarily filming at a slower frame rate 😛

[@doommuffinz5276]

This is the most fascinating think I've finally gone back into my Watch Later playlist and watched.

[@ummdustry5718]

11:00 That there is youtuber speak for "I'm not one of the six people on the planet who understands this phenomenon well enough to explain it so let's not"

[@anderpanders6210]

@@Clifford_Banes What's his main quest?

[@grebe2332]

yeah i'm still confused. given the shape of the submerged part of the boat, how could the water possibly give it buoyancy? it seems like the water can only transmit downward force there

[@davidwuhrer6704]

@@grebe2332 Yes, the buoyancy keeps the ship down. (Although I'm not sure "down" is even the appropriate term to use here. “Partly out of the fluid” seems less ambiguous.)

[@jakemcmillian]

@@anderpanders6210 @Valentin main quest is clearly comedian with Matt Parker

[@xponen]

@@grebe2332 the oil is heavy, so the pressure of the gas below it must be able to hold the weight of the oil. Now, put a ball on the surface of that oil, the ball experience same pressure upward. But the oil exerted a flattening push/pressure due to the dynamics with the vibration, this is the opposing forces that prevent the ball from punching thru the oil.

[@Eldorado1239]

1. Take a chaotic system 2. Shake vigirously 3. Calculate trajectories with confidence

[@Gusto20000]

Submerged upside down - could it be “supermerged”?

[@TrailBlazer5280]

The top and bottom surfaces of the liquid act as sheets as a result of surface tension. The walls of the container are tugging on those "sheets" to change its direction with each pulse and make it float. The tug also evens the surfaces out slightly creating a moment of "tension" thousands of times over. The tension is not perfect but all the iterations dampen the imperfections. For it to work the movement must be at an interval small enough that the tension is not overwhelmed by the weight of the liquid. The tension has some amount of strength, and a falling/moving object will take a period of time to transfer all of its weight onto another object. So the time interval has to be small enough that the weight/force transfer is less than the surface tension's strength

[@coryman125]

I love your philosophy of finding an intuitive explanation. Knowing how something works makes it easier to do the math, but knowing the math really doesn't do much to help you understand what's going on. I'm a little surprised they had you write a question and you didn't do "What is the most interesting thing to pour out of a beaker?" ;)

[@jlinkels]

Very good presentation. Some vloggers think you need background music (in the foreground) or elevated playback speed to demonstrate the laws of physics. These videos of yours are a delight. Thank you!

[@jovangerbscheid4619]

6:32 I did not understand why this is at first: while the pivot point is pushing up, the rod goes from close to vertical to far from vertical, and while the pivot pulls down, the rod goes from far away from vertical to close to vertical again, so it seems to average out and the forces cancel. It turns out that I was confused by the model with the table where friction played a role as well. The force that pushes the rod away from vertical position is caused by the acceleration (not velocity) of the pivot point upwards, so it occurs mostly when the pivot is at the lowest position, so when the rod is closest to the vertical position, which is exactly what you said :)

[@bleuebloom]

I just discovered your channel and I’m really impressed by the production quality, especially given this channel isn’t even about cameras and stuff like that. 60fps is cool, ur using an “edge light” and a fast aperture lens, like daaaam bro

[@AaronMeighoo]

I came here with one question: "What is silicone oil?" I leave with an unanswered question and a new one: _"What the [redacted]?"_

[@thegoodlistenerslistenwell2646]

Scp

[@cezarcatalin1406]

Reverse buoyancy should be an SCP thing

[@750kv8]

en.wikipedia.org/wiki/Silicone_oil

[@750kv8]

@Pronto - Now that's some scientific explanation right there.

[@epauletshark3793]

Thats how I feel.

[@Malaphor2501]

Upon second watching, the upside down boat makes the sense the second wave as buoyancy is basically a result of the interaction between density and gravity. Since you're "circumventing" gravity with the vibrations by moving the water up faster than it can push down on the boat to push the boat up.

[@shashanksinha324]

I saw that levitating liquid and inverted bouyancy video but wasn't able to wrap my head around it,you made it pretty clear. Though I do not understand the whole process but the explanation you provided made intuitive sense. Great work.👍

[@FederationStarShip]

Amazing scientific communication here. Putting the components on the flat table to remove gravity from the picture was brilliant

[@R2D2internet]

8:40 ventriloquism! I love your videos! Also their fixes :D

[@TonkarzOfSolSystem]

Another way the think of the force system depicted at 8:00 is that when the rod is pushed up the pushing force is closer the the center of mass of the rod meaning the the rotation causing component of the force (the "moment" force) is smaller due to having less leverage. A bit like the way a weight on a seasaw has less rotation causing force the closer it is to the pivot.

[@photelegy]

4:20 I want this as an XXL version so that I could dive in it until I dived through the first one and jump into the second one 😊 It reminded me of a part in the movie "A world beyond", when they swam in a levitating water bubble. 10:28 How would it feel to just hold out the head (like the upside down boat) and still don't falling down. 😅

[@vibaj16]

While being violently shaken up and down

[@yvesstocky9936]

That would be fun, but it might colapse then.

[@toadamine]

Shaken swimmer syndrome... lmao

[@shreyasp3287]

Sir your videos inspire us to learn more about the world around us and question the curious phenomenon around us for those of us whose parents didn't went to university you inspired us to take action by these different content thank you

[@lateoclock4281]

I think it's awesome when scientists do things like make their buoyancy test items look like tiny boats. Makes you think they're enjoying their work 👍

[@lelsewherelelsewhere9435]

The vertical pendulum's net difference of forces between "pushing up" vs "pushing down" is why (engine) piston (and rod) movement when at the bottom of the cycle is very different than just the mirror of piston movement at the top of the cycle. It also explains why changing the piston rod length has "weird" effects on where (in the cycle) the piston head moves fast vs moves slow.

[@SmileyFace01]

"To qualify to enter this competition you must be resident in the United Kingdom and aged over 18 years." *Sad Czech noises.*

[@SmileyFace01]

@Evi1M4chine wut?

[@nahometesfay1112]

@Evi1M4chine I don't think you have to spend any money to enter. While these kinds of promotions are intended to make you spend money they can't make you spend money (I may be wrong if the laws are different in the UK)

[@markp5726]

Sorry sir, your application is invalid because you did not czech the UK resident box.

[@SmileyFace01]

:^)

[@barakathiongo4835]

@@markp5726 good one mike

[@Uncrastinating]

Very cool video! Also interesting is seeing the liquid drip from that upside down boat, sort of escaping the tension through that pointy bit on the top!

[@pooyataleb2514]

5:10 it's not what you think mom! I can explain this is an upside down pendulum

[@heathispieces]

My mind has been blown by your last few videos! Keep it up!

[@zedfalcon6972]

10:04 I think the word you're grasping for is "supermerged"

[@zedfalcon6972]

@Evi1M4chine precisely

[@ipbatinic]

My interest stems from the moment you inject air at the interface of the liquid medium and the bottom of the vibrating vessel, you are effectively adding a gaseous spring, or the electrical equivalent of a capacitor, hence the mechanical equivalent of a damper, between the solid vibrating bottom of the vessel and the liquid medium you need to coerce into a vertical oscillatory motion (vertical as in parallel to the gravity acceleration vector). Because liquids are nearly incompressible, and can't easily cavitate at such low frequencies (inertial dynamic forces are too low) then coercing the body of liquid to vibrate with the vessel is intuitively obvious when st the beginning of the experiment, the solid bottom of the vibrating vessel and the denser body of liquid are in full contact. It's mechanically solid linkage between the two. So when you inject air between them, that link becomes a spring. It's like miatching impedance matching, isn't it? The equivalent capacitive reactance of the air has to do with its density, specific weight, and viscosity (environmental coefficients exist, so vessel pressure and temperature would affect that "springiness"). I believe that's why there is instability on both top and bottom of the levitating liquid; there's a time constant because of the air not being solid and this nonlinear, just as in an electrical equivalent circuit (low-pass filter, or R-C). I'm guessing that chaotic oscillatory "noise" we only see once the air is introduced, could be attenuated by better matching the impedance (electrocal equivalent of AC Coupling) by using a denser gas (a bigger capacitor) because your oscillating frequency is pretty low and your liquid is pretty heavy, therefore its inertia calls for a stronger coupling. Impedance matching like the fluid they put on your skin to better couple the ultrasonic frequency from the probe elements to your body. Is this insanity or is this a positive contribution to refine the understanding of the second-order dynamics we can observe from this apparatus? By the way, maybe this helps: In terms of density, the upside down boat is no different than the air layer underneath the body of levitated liquid - the air *must* float underneath the liquid just as the boat does. Lastly, before the bonus question, what happens if you inject silicon oil at the bottom? Does it just float back to join the silicon oil on the top? I don't think so, because it's like the boat. It's has to float on the surface even if upside down. Right? In a weird way, the underside of the levitated liquid is a inverse buoyancy universe. Not exactly a diode bit :) BONUS QUESTION : The question is, if you had a heavy load to the low-pass filter, you would normally see attenuation; But we see chaotic noise, not standing waves of surface perturbations. What is causing that mechanically chaotic noise in a closed physical system? Scroll for a theory... Though there's only one oscillating driver at only one single frequency, and to boot, it's presumably a sinusoidal wave, hence no harmonic content, but even if it were triangular the harmonics are a multiply of the fundamental frequency (120Hz) so they don't interfere and cause chaos. But I think the topside of the levitated liquid interacting with a less dense liquid is like an inductive load and the levitated liquid is the equivalent of a transmission line. Of you don't match impedances throughout the system, you will get reflections of unabsorbed energy (electrically bad or no termination so your signal rings) and those reflections are chaotic because of many factors like the propagation time of sound through the differing fluids, etc. If you ever read this, please correct me. I could really use a prize: Give me 5 minutes in your office waste bin. Thank you so much for your amazing and inspiring videos!!

[@NicklasUlvnas]

05:08 I will not ask what else you use that thing for...

[@matteo234321]

The last part where the boats seem to float up-side down really looks like a nice segway to gravitational fields. I look forward to your videos!

[@generalpartridge7653]

Awesome explanation, 3rd year physics undergrad here and always love watching your videos. Don’t suppose you’d do one on complex networks? (My dissertations on it haha)

[@wesleyooms]

Thanks for this great video. I like your intuitive approach to explain the stability of the vibrating inverted pendulum. You can even explain the stability of the vibrating inverted pendulum without mentioning forces and vectors (which is already quite advanced for children in elementary school) When pulling the rod, it acts as a hanging pendulum. When pushing the rod, it behaves like an inverted pendulum. The time it takes from a perturbed pendulum to move towards it's equilibrium point is much shorter than the time it takes for an inverted pendulum to move from it's equilibrium position towards a small displaced position. It's not as accurate, since it's a little more complicated than that, but it's even more intuitive.

[@johnchessant3012]

The inverted boat broke my brain. :(

[@cezarcatalin1406]

Windows blue screen intensifies.

[@xponen]

the air pressure underneath the oil is high, it pushes the boat/ attempt to punch the boat thru the oil, but the vibration of the oil exert a flattening pressure on the oil, and the boat must resist this pressure. So when air pressure is equal to the flattening pressure then the boat stayed at the oil surface and never punch thru.

[@Rabbit-the-One]

Sorry

[@fewwiggle]

@@xponen The boat is still denser than the air, so the boat should fall toward the earth. IOW, the high pressure air pushing the boat up is not the explanation.

[@xponen]

@@fewwiggle that's like saying "denser than air contraption cannot fly". The reason it float is because the pressure is higher underneath the oil, the oil has lower pressure, ie: lift. You can test whether this is true; if it is true then when the boat detach from the oil it will fall to the bottom, if it is false then when the boat detach from the oil it will float back to the oil.

[@korumann]

Glad to see Steve taking part in the "Expanding on something Steve Mould made a video about a few years ago" genre.

[@djdrav]

8:40 Your voice says liquid, your mouth says water. Noice dub.

[@b33thr33kay]

Man, you're so good at communicating science.

[@radicalxedward8047]

I was just watching a video yesterday from Cody’s Lab about floating a liquid on a gas (gallium on xenon I think). Weird timing.

[@derp-construction3341]

This explains how the multi level river worked in that Chronicles of Narnia book.

[@faxezu]

I think where is a typo in the thumbnail 😅

[@shanonfrancis5071]

There's a typo in your comment though.

[@georgplaz]

is there? which?

[@faxezu]

@@georgplaz silicon was written Silocon.

[@faxezu]

@@shanonfrancis5071 I have an extra w if you want to buy it 😁

[@richardpike8748]

Loved your pendulum explanation with the torque and perpendicular forces, actually quite intuitive!

[@HelloKittyFanMan.]

"If you think about it some more..." and some more and some more.... This is why we have some very indecisive people! Actually, on second thought, maybe it's not.... ...Or IS it?

[@HelloKittyFanMan.]

Wa wa waaa... @Evi1M4chine couldn't get my JOKE!

[@ashtonhoward5582]

I now want my desktop background to be a shot of the two boats floating on the liquid.

[@2nd-place]

I hate silo cons. They don’t install the proper safety systems for grain storage.

[@Theinatoriinator]

the grains always so wet and it molds and rots.

[@ericl8743]

You store silage in silos. You store grain in grain bins. Silos are sealed containers of a glass layer on steel which is why they're very dangerous to enter. A grain bin is just an empty hopped with a cover on top

[@ericl8743]

www.ilfbpartners.com/farm/the-difference-between-grain-bins-and-silos/ Hier ist eine Webseite, die den Unterschied erklärt. Grain bin ist für dad Gran (auf Englisch) und ein Silo is fur die Silage. Sorry for my poor German. I only speak English and French

[@1495978707]

The reason that the buoyancy makes sense is that density is actually not what causes buoyancy. It’s a pressure gradient. If the pressure gradient provides a great enough buoyancy force to balance gravity, the thing will float. USUALLY density tends to decrease with height, and so that is what our intuition is based on. Same thing with displacement. Displacement is a way of simplifying buoyancy calculations, but you have to always remember that the buoyancy force is a surface integral of the pressure vector field. In normal circumstances, pressure increases with density. Lower things are more dense, and the lower you go, the greater the pressure. This is how your intuition gets mixed up. If you managed to balance honey or silicone oil without any of this vibration to complicate things, the pressure in the oil would be LESS than that of the air below it, despite being more dense. In the stack of air honey air, you still have pressure increasing with height, because boundary conditions have to match. The pressure at each interface has to be the same, or the interface would move. Now because the honey is denser, the pressure would vary more quickly with height inside it. But the boat is drawn upwards because the pressure in the honey is lower than that of the lower air pocket. You have to remember, force is what ultimately determines the dynamics, density leads to pressure which gives force, and changing the situation makes the derivation of force from density change since the assumptions you make are different.

[@butterflygroundhog]

"Vibration generator Ahh, the scientific way of saying a vibrator

[@davidwuhrer6704]

An unstable vibrator would do, but there are other ways to generate vibration. The implementation detail doesn't matter, only the effect.

[@davidwuhrer6704]

@Pronto I don't know, it seems catchy.

[@11mitsaras11]

I just saw the upside down boat and my mind is blown. Of all the things I've seen on KZbin, this is my " Does not compute " moment! My reality just divided by zero.

[@Friday_WasTaken]

od di just saw another video about this and the vid wasn't even new. it had a little boat floating upside down :)

[@Friday_WasTaken]

hmm infact the exact video i saw is featured in this viod :P so maybe it wasnt as old as i though :P

[@minefreak2000]

If you think about it, this is a really good demonstration of why a semi truck should slightly accelerate throughout a curve in the road, in order to stabilize the trailer behind it. Neat

[@U014B]

5:53 [Matt Parker wants to know your location]

[@Rick-the-Swift]

I hate that we have such a love/hate relationship with all those darn sneaky scientists whom we rely on and mistrust all at once. Why can't they all be more honest and upfront like this man? very enlightening.

[@AverytheCubanAmerican]

Oil? Oh boy, a certain military is gonna invade your channel

[@cezarcatalin1406]

Greetings comrade !

[@jankkhvej]

I would choose Fasthosts for that question about RSS, if I weren't the hosting owner myself. Excellent video also, thanks, Steve!

[@arshaamkabeer7901]

0:11 I read that fast thots

[@jovangerbscheid4619]

Apparently you can make an unstable equilibrium stable by frequently making it stable for very short periods. That is the general rule in this video. That's amazing!

[@johnnybravo4733]

Americans be like: “OIL? 🤨😮”

[@davidwuhrer6704]

European: Palm oil?

[@CharlieMayer1986]

Um, no? You can go have a play-party with OPEC and I'll stick to learning as much as I can about scientific quirks and quarks. I encourage you to embrace learning instead of disparaging othere.

[@davidwuhrer6704]

@@CharlieMayer1986 But you know what he is referring to.