The Levitating Liquid Pendulum

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I'm reluctant to say "gravity defying", but come on, this is cool! You can levitate a viscous liquid just by shaking it! Not only that but a buoyancy effect appears on the other side. I also show Kapitza's pendulum.
Here's the playlist of videos that feature the stroboscopic effect:
• Videos featuring the s...
Here's the original upside down pendulum video:
• Upside down pendulum
David Acheson's books are here:
academic.jesus.ox.ac.uk/dacheson/
The Kapitza pendulum paper is here:
butikov.faculty.ifmo.ru/InvPen...
Here's the research that lead to all the nice levitation footage from Benjamin Apffel, Filip Novkoski, Antonin Eddi and Emmanuel Fort:
arxiv.org/abs/2003.04777
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stevemould.com/books
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[@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!

[@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.

[@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...

[@rubeningels5060]

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

[@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.

[@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

[@nickjanssens1045]

Wow, I've seen lots of mind-bending science youtube videos but a boat floating upside down on the bottom of a levitating lake of silicone oil might take the cake. Great video!

[@JHA854]

"Here is my vibration generator" Okay, Steve.

[@markm0000]

Steve’s wife: Give that back!

[@boxed_in4357]

@@markm0000 holup

[@chrisbustos1431]

@@markm0000 😏

[@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

[@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.

[@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

[@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.

[@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.

[@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.

[@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

[@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

[@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"

[@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!

[@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!

[@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

[@yajnavalkiagargi8100]

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

[@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

[@WhiterunGuard11998]

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

[@StraightOuttaJarhois]

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

[@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!

[@richardpike8748]

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

[@Billiegoose]

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.

[@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.

[@pawelmiechowiecki7901]

I am fixing my car light and TV this way

[@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?

[@heathispieces]

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

[@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.

[@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.

[@reeeil]

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

[@philipmcbride3900]

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

[@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

[@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"

[@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

[@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.

[@Terrain239]

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

[@rensvanbreukelen3762]

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

[@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!!!

[@doommuffinz5276]

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

[@thedoubster]

You are fantastic at explaining things and this is crazy stuff god bless Steve Mould

[@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.

[@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...

[@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!

[@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

[@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

[@thePronto]

It's something that plastic surgeons sell to women for $5,000. Fully installed...

[@750kv8]

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

[@R2D2internet]

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

[@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.

[@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!

[@pooyataleb2514]

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

[@Anton-cv2ti]

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

[@silvenshadow]

Great video and something I've never seen before. Truly amazing content.

[@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.

[@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.

[@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

[@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!

[@anonymous.youtuber]

Astonishing ! If it weren’t your video and explanations I’d be suspicious. Great vid as usual ! 🙏🏻

[@zedfalcon6972]

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

[@zedfalcon6972]

@Evi1M4chine precisely

[@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.👍

[@jannehuhtala]

What a great analogy again! Thank you for the video!

[@nikosrouselis2317]

It's been a very long time since i've seen such an interesting video... Thank you.

[@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)

[@Gusto20000]

Submerged upside down - could it be “supermerged”?

[@danielorta8563]

Your explanations are incredible. Thank you!

[@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!

[@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!

[@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 👍

[@SkyraHope]

This explains a lot of things for me! Thank you!♥️👍🌟

[@AlexMoreno-zj7po]

excellent pendulum explanation on the table

[@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

[@loganstrong5426]

So, effectively, "How to film the upside-down boat scene from Pirates of the Caribbean."

[@ashtonhoward5582]

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

[@animalbird9436]

Yeh m8. Very knowledgeable.. 1st time watcher and impressed.

[@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 :)

[@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.

[@chichcnc]

Wow. That was a great video Steve Mould

[@omshakal]

Thank you Steve, I'm guessing this is the final key to my perpetual motion machine.

[@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?" ;)

[@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

[@b33thr33kay]

Man, you're so good at communicating science.

[@lucasbattistella5400]

I can not believe you just explained that Pirates of the Caribbean scene where they flip the boat

[@djdrav]

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

[@Ecktor]

9:46 Are serious mr Mould? 😂 Reverse-buoyancy?! 2020 cannot ever surprise me, but turns out you still can! 🤣

[@cezarcatalin1406]

2020 can’t surprise you ? Ha ! I bet you aren’t prepared for the Christmas surprise !

[@blaineburgess]

This just blew my mind when it clicked in my head. That’s just... i loved this

[@CutcliffePaul]

Brilliantly explained. It's good to understand somethng intuitively, even if you have to do some non-intuitive work to get there.

[@defalt2900]

I can't wait to create precarious equilibrium with honey every time I use it now!

[@NicklasUlvnas]

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

[@krystofbohac5313]

Physics just never ceasees to amaze me!

[@Ciencillamente]

Woaaahhh!! that was amazing!! Thanks a lot Im working with acoustically levitated droplets of water, not the same or even a similar system, but also cool

[@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.

[@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 😁

[@stephenstreet1045]

Smashed it again Steve.

[@siepkevankeulen]

This video is both mind-blowing and so so relaxing xD

[@TheWolfboy180]

10:05 Supermerged?

[@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.

[@thePronto]

4:40 a prototype impotence cure combined with a sex toy that Steve is planning to bring to market. I don't recommend "Kapitza's Pendulum" as a brand name...

[@davidwuhrer6704]

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

[@bscutajar]

This was absolutely fascinating

[@grazedrightbeef8921]

That was such a good explanation

[@U014B]

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