Capillary Tubes In a Vacuum Chamber-Negative Absolute Pressure (Part II)

[@TheActionLab]

Cool paper on negative pressure published in Nature Physics: www.nature.com/articles/nphys2475

[@KnotRight4Ever]

I think u just explained why dark matter reacts to the universe by expanding at a constant endless increasing speed. I still think dark matter is just matter with a negative charge nucleus not like anti-matter with a anti-proton but actual electrons with protons revolving around them I know the math has never worked out on this but I think if someone could make a negative spectrum reader we could see this also I believe it's why dark matter has force interaction with matter but doesn't interact with it chemically because the outer atoms attract (-) an (+) but the they can't jump to nuclei. It would probably mean that dark energy is positively charged positive energy and that's why we can't see it it's not giving off radiance jumping, it's energy that's attracting it which causes darkness by removing light not the absence of it, I think this attraction is matter acting like the liquid in ur example under a negative force pulling itself into existence. I think if dark matter didn't exist photons an other subatomic particals wouldn't act sporadic they'd act like atomic particals (non-quantum), light could sit like a heavy gas or liquid.

[@energyforever720]

hello fellow human. except for the word capillary, not sure how relevant this comment is to your video. i was interested in seeing how capillary action works and wondered two things: 1: why doesnt capillary action occur with a regular straw for beverages? 2: if part of the reason the liquid climbs up a tube is due to the liquid being magically attracted to the surface of the tube, why doesnt the liquid climb the outside of the tube? i did wonder something about your video: if the pressure of the air is higher than the pressure of the liquid, would that be equivalent to saying the force of your hand pushing down on my hand is more than the pressure of my hand pushing upward on yours? if so, and your hand represents air and my hand represents liquid, would the logical conclusion be that your hand would overcome the force of my hand and therefore push my hand down aka the air pressure would overcome the pressure of the liquid and therefore push down on the liquid? if so, it would seem logical the air would push down on the liquid until the liquid was level, and so, it would seem there is a force greater than that of the air pressure, which allows the liquid to pass the zero point, which actually creates a positive pressure. i literally got kicked out of school so i have no conventional education to compare your logic to, but, to me, according to my logic, your logic is backwards. maybe you did that intentionally or maybe you were taught backwards or maybe something else. who knows for sure?

[@craigslist6988]

I wish I didn't watch this. This is more wrong than the short! You doubled down on the wrong here... Turning the adhesion into a pressure is a terrible idea for teaching. Engineers use pressure very abstractly sometimes, like with the lift for an airplane wing, because the math works and happens to capture the physics well. So I can see why you might hear engineers talking about negative capillary pressure IN SPECIFIC CONTEXTS, but it's a really confusing educational explanation. You might as well say it happens due to the lower entropy of even liquid heights. Like, yeah, the entropy of equal liquid heights in this case is lower than the unequal case... but if you explain it that way to an undergrad class it's going to be.. high entropy.

[@norbertfeurle7905]

The liquid is not at a lower pressure than the atmosphere at the top of the tube, because as you said correctly in another video there would be movement if it where. The liquid at the top of the tube and the bottom of the tube near the rest liquid is at about the same pressure, because some of the liquid normally occouring downward force due to gravity is cancelled by the adhesion force.

[@grahambarden7632]

ACTION LAB - You need to address GRAVITY and its role in balancing how high the liquid travels in the tube. Negative pressure is not a force - like "centripetal force" is not a force!

[@stuckinfirst]

Congratulations, Action Lab, your channel has matured to the point where you no longer need to do a countdown before turning on your vacuum pump.

[@ThePrufessa]

I think you just caught him slipping. I'm pretty sure he still does the countdown. But maybe he did give it up. Good catch cuz i didn't even notice.

[@samuelplyr99p]

4:30 he certainly did count down

[@gregdwilson2]

Thank you for addressing some of the problems with the last video, however, I think there are a few things that need clarification. "What causes water to flow is pressure deltas" is not categorically true. Any object moves because of the net forces acting on them. Because multiple forces play an important role here, you cannot just say that it is pressure causing all of this to happen. It is not simply pressure that raises the water in the capillary tube. It is because the forces of water tension, gravity, adhesion and pressure all create a net force upward causing the water to rise. An important thing to note is that this changes throughout the water because different forces are acting on different parts. For example, the adhesion forces only occur on the edge of the container. The surface tension only occurs at the air surface interface. Water pressure only occurs below the water air interface and changes as a function of depth and the inter-molecular forces cause there to be negative pressure in the water. Once the water rises to an equilibrium point, you still have pressure deltas, but no flow because ALL of the forces in this complex system have balanced out. Trying to state it is all pressure is very very bad practice. When you dump some water on a hill and watch it flow down, you wouldn't say, "Pressure differences in the water cause it to flow down the hill." You would say, that gravity and normal forces cause the water to flow down the hill. By pumping out all of the air in the vacuum you showed that atmospheric pressure didn't effect capillary action. This shows that atmospheric pressure does not account for the rise but it is entirely due to water, thin tubes, and gravity. Just tip the entire thing on its side and you will see the shape and height of the meniscus suddenly change which shows that just relying on pressure is dangerous. Horizontal capillary tubes are an entirely different experiment with their own fascinating effects.

[@TheActionLab]

Gregory Wilson actually talking about forces and pressure is the same thing. And yes when water flows down hill you do need to talk about pressure deltas. You can use fluid dynamics to calculate the pressure differences in the flow using navier stokes equation. Fluids flow due to pressure. You can call it a force but it’s harder to deal with forces in fluid dynamics than pressure. Fluids moving anywhere is a fluid dynamics problem and if you want to know why or when fluids will flow you have to calculate pressures. That is why I’m talking about pressure. Any paper that has to talk about fluid movement must discuss the fluid pressure.

[@gregdwilson2]

@@TheActionLab Forces and pressure are not the same thing. It's like saying mammals and cats are the same thing. Pressure is indeed a force but force is not always pressure. Pressure is only one type of force. Is it important? Yes. Is it adequate? No. While I agree that it is important to talk about pressure, you can't say that pressure is the only thing at play here and describe it in terms of only pressure. Even in the Navier-Stokes equations you explicitly define other forces (apart from pressure) acting on the continuum such as gravity. So in the general equation it is pressure AND gravity that causes flow, not just pressure. Throw in the capillary action and you have the adhesive force and surface tension that now need to be added to the equation. You cannot say it is only pressure, it is ALL of those forces . Take this quote from a professor at Boston University, "There are basically two ways to make fluid flow through a pipe. One way is to tilt the pipe so the flow is downhill, in which case gravitational kinetic energy is transformed to kinetic energy. The second way is to make the pressure at one end of the pipe larger than the pressure at the other end. A pressure difference is like a net force, producing acceleration of the fluid." Look up experiments of capillary flow on the international space station. This is actually a problem in liquid rockets. Gravity has changed which drastically changes fluid dynamics. I understand trying to simplify it but you have thrown out the dishes with the dish water.

[@TheActionLab]

I actually never said that pressure is the only reason for anything in this video. I’m not really sure what your point is here. In any calculation you have to account for all forces/pressures. Of course that’s true. In this case capillary forces create a negative pressure. The difference in pressure can be calculated like this: deltap=2*gamma*cos(alpha)/r where gamma is the surface tension between water and air, alpha is the contact angle of water on glass and r is the capillary radius. Thus you can use this pressure to calculate exactly how high your water will rise in the tube under any circumstance (centrifuge, normal gravity etc.). This is very useful. I’m not sure what your problem is with mentioning pressure in a capillary tube. And edit: I just realized you said pressure is a “type of force” what on earth are you even talking about? Pressure==force/area. It’s not a type of force.

[@gregdwilson2]

The Action Lab The problem arises when you try to link the atmospheric pressure with the liquids pressure to describe capillary action. Your balloon example is exactly this. It’s an incorrect way to describe capillary action and meniscus. Apart from that, I never said I had a problem talking about pressures in the liquid. I just said don’t forget the other physics like gravity. As far as pressure being a force I was generalizing it to the pressure term in the fluid dynamic equations as something that can cause acceleration. Yes yes, pressure is not a force, but pressure differences in a liquid result in net forces on water molecules that cause acceleration. I agree that the wording was not the best but it was pretty clear what I meant. Pressure differences can cause water molecules to flow. Gravity can also cause water molecules to flow. These are independent terms in the fluid dynamic equations. The comparison is pretty clear, especially when looking at the equations. I still think you are missing the point I was trying to make. I’m a little confused as to why you are dead set on explaining this phenomena in terms of pressure. Help me understand your reasoning because I don’t believe it makes your explanation easier to understand, especially for the casual KZbinr.

[@alphadraconis9397]

@@gregdwilson2 I think James wants to explain this phenomenon in terms of pressure and not gravity. It would be cool if he could tilt the tubes in vacuum. Since capillary action is pulling up the liquid here, and in vacuum there is no air to push on the liquid, gravity is actually pulling the liquid down.Correct me if I am wrong but I noticed the level of liquid in all tubes remain same even in vacuum when not boiling , around 6:17. So I think both of you are almost correct. Each factor is occurring independently and they are interacting and cooperating to make up this complex system. Here James is not tilting so he does not take gravity into account I think.

[@Bigfoot_With_Internet_Access]

When you realize you can have negative pressure *Confused screaming*

[@reyalexisjelly]

Just Some Bigfoot With Internet Access isn’t negative pressure just like blowing something up?

[@thunderman0880]

Yes, it is called tension

[@thunderman0880]

rey alexis it is tension

[@pulsegamingbird3764]

So what your saying is if i pull on something then it has negative pressure?

[@Tyrian3k]

A liquid can only flow up if there is a force pushing it up. In a normal container, gravity is pushing down and the water pressure is pushing it up. Both are equal, so no movement happens. In a capillary, the forces pushing the water up are the pressure of the water plus the adhesive and cohesive forces, so it rises above the level that it should until it reaches the point where equilibrium is reached again, i.e. P0=PI. If, as you say, P0 > PI, the water would flow, as you yourself said in the beginning of the video. Specifically, it would flow down until PI=P0. Moreover, if the water's pressure at the top of the capillary was lower than everywhere else, it would have boiled there first. Pressure is basically the combined forces of molecules bouncing off a surface. Asserting that there is such a thing as negative pressure is to assert that particles can travel at a negative speed and possess a negative amount of kinetic energy and a negative momentum. Also known as complete nonsense.

[@mymoomin0952]

Negative pressure is effectively tension. If you wanna know more you can read the Nature article in the pinned comment, or the Wikipedia article if you want something more approachable.

[@akshayvinodnair]

I think negative pressure just means that the force causing it is in the opposite direction but that doesnt mean that negative pressure is less than absolute zero pressure cuz the negative sign indicates the direction and is not related to the magnitude of the pressure otherwise it will be like saying that temperatures below 0 K exists

[@brando3342]

Next video: "Stretching liquid in a negative zero pressure atmosphere".

[@_Killkor]

warming it up using laser with negative Kelvin temperature

[@quirtt]

@@_Killkor XD thats actually impossible

[@Nick-Matchem]

Himadri Mandal I think that’s the idea

[@dan2800]

creating -0 pressure

[@babyskeleton7990]

@@quirtt is actually possible to create negative temperature using laser

[@RBLXProd]

Disconnected from the server Banned Reason: Breaking Universe Law [ disconnect ]

[@Dondlo46]

NOO YOU CANT JUST CHANGE LAWS OF PHYSICS haha pressure go boom

[@ThePrufessa]

You can't just change the spelling of physics

[@EliteCubingAlliance]

ThePrufessa 😂😂😂

[@Dondlo46]

@@ThePrufessa lmao forgot how to spell

[@ThePrufessa]

@@Dondlo46 lol you set it up so perfectly i couldn't resist.

[@legacyconsolegod9261]

I hope the devs don’t patch this bug.

[@JanmajayMandal]

It's virus not a bug

[@dan2800]

@@JanmajayMandal its a feature not a bug or virus

[@FrozenLabRat]

They have still not patched the quantum tunneling glitch. Where is the bugreport?

[@thngzys]

If they do, plants would be dead. I bet another dev has commented "Don't touch this or you're fired, black magic here." beside the function.

[@netpilot5]

"Negative Pressure" does *not* mean what you are describing! Pressure is a quantity of force over an area. By definition, force is a vector (i.e., it has a direction.) Also, pressure is always normal (i.e., perpendicular) to the surface it acts upon. The negative sign in front of pressure does not mean that the *quantity of pressure* is negative. It means that the *direction of the force* is in the opposite direction. Michael S. Turner, a theoretical cosmologist who coined the term dark energy in 1998, summarizes the concept of "Negative Pressure" in an article in this way: "... it's direction - an inward, imploding, or contracting force, rather than the outward-pushing force typically defined as pressure. The minus sign next to those atmospheres doesn't mean "less than nothing"; it's an arbitrary signifier denoting *"in the direction opposite of positive."* (my emphasis) Solids have negative pressure when they pull in, like stretched rubber bands or springs. Liquids can have negative pressure in metastable states, when they resist turning to vapor." The excerpt quoted above is explained quite clearly in the context of this 2003 _Discover_ article titled "The Physics of Negative Pressure": www.discovermagazine.com/the-sciences/the-physics-of-negative-pressure

[@srpenguinbr]

Isn't that what he said? That negative pressures mean tension instead of compression?

[@Pika250]

This is exactly how such trees as redwoods and the like operate; they use the roots to pull water from the soil, through the xylem (which plays the role of the capillary tubes), and into the leaves where it just evaporates. I recall watching a video by Veritasium about this not too long ago.

[@Abish_]

🔴 P°- P1= 2S/R where, S=Surface tesion of liquid R= Radius of tube

[@TheActionLab]

Abish Adhikari don’t forget to times by cos(alpha) where alpha is the contact angle of the liquid:)

[@Abish_]

@@TheActionLab kzbin.info/www/bejne/aKi5g2yjbbKrhZY Time stamp : 25:35

[@justsomeguywithasmolmustac9476]

@@Abish_ Bruh can he understand Hindi??

[@n0nenone]

@@justsomeguywithasmolmustac9476 lmao no

[@Abish_]

@@justsomeguywithasmolmustac9476 he can see the formula in that video

[@grahambarden7632]

I think you need to acknowledge GRAVITY in your discussions! That is why the capillary action reaches an equilibrium. In blood pressure manometers and thermometers, there is a vacuum above the liquid and the mercury rises to the point that gravity determines- as you mentioned, no glass interaction. But I learned from your video!

[@danielleohallisey4218]

I appreciate your thinking but wonder if you’re not conflating adhesion force with pressure? In other words, instead of P1

[@JohnH0130]

1:21 "...at the water liquid interface, the pressure in the liquid is below atmospheric pressure." Intuitively, at first I was tempted to disputer this. But giving it more thought, I see you are right, based on a force analysis at the surface layer. The surface layer is stationary because atmospheric pressure is pushing it down, capillary forces are pulling it up, and the liquid pressure is also exerting an upward force at this point....and the sum of these forces has to be zero net force. This only adds up if the liquid pressure at the interface is below atmospheric pressure.

[@zka77]

P1 < Peanut

[@marydavis9557]

YOU should totally make a video in regards to NASA release of “UFOS”. I don’t know if you do that type of stuff. But I love how you explain things so I could enjoy that video!!!!

[@Bnslamb]

Navy release, not NASA.

[@marydavis9557]

ooooo okk thank you thank you ❗️ I wasn’t sure

[@milos_radovanovic]

Ok now you definitely need to show us the Schlieren photography of that phenomenon! Or if it exist, some kind of pressure sensitive color indicating liquid (like liquid crystal or something)

[@DANGJOS]

@The Action Lab 3:07 Here you have that *Po* is larger than *P1* but the *Po* above the meniscus is also larger, yet there is a flow upwards. Perhaps there is an even lower pressure near the walls that allows for a pressure differential?

[@IrocZIV]

So... If liquids have different surface tensions do they react differently with capillary tubes?

[@h7opolo]

thanks for revisiting this concept for a more detailed explanation.

[@decodedbunny101]

Ahhh yes I’m still in high school Learning pressure But I fail other subjects

[@ThePrufessa]

I sell pressure. 8ths only.

[@justincoleman9776]

Learn your pressure well. Once out of High School, the pressure goes waaaayyyyy up

[@tamjidtahim3422]

no matter how early i come the comment section is always filled with likes

[@jindivik321]

you come early often?

[@inventsc]

Brillaint video .. loved this one and how well you carefully demoed and explained it.. also on the references to nature …

[@davidhenningson4782]

Great video! Interesting 👍

[@DANGJOS]

@The Action Lab Do you think you could do a video demonstrating Rayleigh scattering? A few partially wrong explanations by certain physics educators are out there too, so it would be cool if you could give an electrodynamics explanation as well.

[@markinipannini]

Pressure was so low it made his moustache uneven 😳

[@komalkuku]

I really hated this topic because i couldn't understand it howmuch i read but since you explained it i think i can understand it a little better

[@rohitgolabhavi]

Ur voice is too good Bro 💎😘

[@button_bud3759]

R u a bot ? Like an automated comment program

[@MuhammadDaudkhanTV100]

So super nice and great full

[@Fahnder99]

6:30 I'd say no, because it's in a steady state and hence at the top of each surface, the pressure is almost zero (according to the quality of the vacuum and adhesive forces between water and glass). Orelse, water would be flowing. But towards the bottom of the tube, it raises due to gravitational forces. I think, you could measure that.

[@jang.pichert2852]

This is really funny, al thou there is a lot of possible force at play there is no way a pressure can be less than 0 by definition.

[@TechsScience]

Can you make a perpetual machine using capillary action?

[@Andreadel96]

I would not think so. The same energy that you could get by the water moving into a tube would be needed to get the water out again. I think you could compare this to water moving from a high place to a low place. You can extract energy from that, but afterwards you have to move the water up again, using up the same amount of energy.

[@iridium1118]

Techs Science ask the 1st and 2nd law of thermodynamics

[@macrovideo2691]

Another Cool Video.. so much love your work… I'm always inspired of the action lab so cool to watch… more power thanks..

[@WouterVerbruggen]

For extra understanding, think of pressure as a force per area. So under tension, there's a negative force per area, hence a negative pressure. Fluid physics things like this are fun, but the math is horrible. Our faculty has a fluid track, teaching things like capillarity and advanced fluid mechanics, which are nightmarish if you're not a math genius. Glad I went into material engineering physics 😆

[@ThePrufessa]

This was very good backup information. A breath of fresh air from all these other idiots that have no idea what they're talking about.

[@ThatCat-aclism]

To expand on this idea. If you had a secondary layer that increased the relative pressure of atmosphere around the entire thing to say. +10atmospheres then you could continue to lower the internall relative pressures and use the zone at p1 similarly to how we use ground in AC electronics. So we only need relative -12/+12 and 0v In this we would have -10P0/+10P0 /P1

[@王海宁-h7e]

Thank you! I've been confused by the extreme negative pressure that can occur in a capillary tube and you clearly explained it to me! BTW, is there any published paper addressing on this issue?

[@lochanjain6301]

Same just same thank u very very much for doing this ❤️ thank u alot Because it's a those thing which I think before sleeping..

[@Casbelu]

Ok, to be consistent and respectful, I feel obligated to comment again...this time I was able to avoid rage commenting throughout the video lol. 1) regarding the balloon analogy. Your still conflating. Your defense of it is just the shape of it. If that’s your only point...ok...I guess. But that wasn’t your point. Your point initially was that you used it as proof positive of the pressure differences. (See this balloon in a tube, see the shape? That’s because it’s at a higher pressure than the surrounding air...see the shape of that miniscus? Aha! Proof positive. No...no, that is not the way any of this works. You might has well compared it to the shape of a sausage and defended your comparison in the same way. You openly admit several times throughout the videos that the miniscus has the shape it does because of the adhesion forces to the wall. You mercury example is actually perfect. It doesn’t have that shape why? Because it is repelled by the wall...water does why? Because it is attracted to the wall....ok, exactly-your admitting/acknowledging the point. So stop pretending it is somehow an evidence of your pressure differential theory. Another way you could Prove it is just to take your setup, measure the minisci, then add another larger tube to the end, and remeasure. If your theory is correct, then all the meniscus shapes would change, because you now have a even higher pressure differential. That won’t happen, the shapes will remain, because they are formed from the hydrophilic interactions with the wall...not a pressure differential. So, can we please not pretend what you said here made any sense? Thanks... 2)regarding the experiment as a whole, contrary to the first point, I had to do some honest introspection watching the video. My gut reaction was “ok, in a vacuum you no longer have the atmosphere pushing down, which is what (by my own admission in my prior rant) cause the water to be pushed UP. So...if we remove that, the tubes should equalize. When that didn’t happen I had to strongly consider I was wrong. That is the logical, humble thing to do when your predictions don’t work out the way you thought they would... Had the alternative explanation you offered been logically sound, I probably would have just stopped there, but it wasn’t. This caused me to contemplate where my own prediction went wrong, and the. I had a 🤦🏻‍♂️ moment.... Of course the tubes didn’t equalize... 1) (minor) the smaller tubes have a relatively higher attraction force to the wall, relative to their size. Think about it like this...you put Velcro on 2 different walls, glass/Velcro. Then let it go. The wall with Velcro will stay high, while the one with glass will drop. A better (less binary) example might be jelly on glass vs carpet. The friction is higher in one, so it “holds it up”. With this in mind, and interesting experiment would be to pour the liquid in a vacuum (as apposed to applying the vacuum after). Since the attraction to the wall should not cause water to climb up (more than the effect of te water planing out) but only adhere laterally, this may prove / disprove one of our theories. I think the fundamental thing that is bothering me is that you keep making an observation, and trying to cram it into your prior. The balloon / tube thing was a good example. Observation (hey...that shape is similar) prior (what makes shape 1 must make shape 2). No, different principles. Pressure is a force, there is no such thing as a negative absolute pressure. The force created by a vacuum ISNT created by the vacuum directly, it is created by he atmosphere pushing, and you removed the force pushing back. Pressure is something, vacuum is nothing. You can’t have negative nothing. Light is something, darkness is the absence of light. You can remove light which makes dark, but you can’t and absolute negative light (absent maybe dark matter? Or anti-matter?) in the same way, you can remove pressure, but you can’t truly have a “negative absolute pressure). These videos were all based around this observation, that you kinda crammed into “hey, it’s like there is a negative pressure”. No, no there isn’t, there are other forces at play here. Redefining tension as “it’s like a negative pressure” is exceedingly aggravating. So, are we going to start saying if I tie a rope to a brick and lift it up, I’m applying negative pressure to the rope? Common, really? Is that what we are doing here? Anyway, all in all keep up the effort / content lol, rant over :). Oh, and, thanks for doing the follow up! I think it’s interesting to have several follow ups on a video, because it lets people chat, give views, and then validate/invalidate thoughts. I think that’s actually really valuable. I was actually responding with another explanation that when I did all the math, I found I made a silly baseline mistake in my assumption. That’s valuable. The Socratic method of exploring is valuable, and I think the videos are good in that vain. :). And, who knows-I too cold be completely ignorant, we never learn if we aren’t open to the possibility that we don’t know :).

[@revcrussell]

This is why a little knowledge is a dangerous thing. No, you can't get negative absolute pressure, that is the point in calling it "absolute pressure". No, water doesn't just flow due to pressure differentials, as seen by this capillary action. P = ρgh is a generalization and doesn't apply to capillary tubes. The pressure that drives the water flow is actually coming from the water itself, not the air pressure *just as your experiment shows* . Actually the rise of height in a capillary tube is *not* dependant on pressure at all, see Jurin's law.

[@gertrude1310]

Probably a dumb question, but could you use that effect to create an infinite fountain (assuming you curved the tube like a faucet and had it low enough, but not as low as the base level)

[@Alittleguy_]

How would that work?

[@delusion2694]

My mom: what you watching. Me: uhh... watching a dude teaching me that liquid has negative pressure. My mom: NUNI

[@emojiguy6374]

Nice moustache !

[@troywhite6039]

Have you tried filling it until the capillary tube overflows but attaching another tube that feeds the overflow back into the large fill chamber. Would that cause a constant motion of it flowing into the fill chamber as it is pulled through the overflow tube via gravity and vaccum and capillary action forces all working in unison?

[@abdulrhman5502]

The water is begin "pulled up" by the tube so when it reaches the top there is no force acting on it to make it flow over

[@al1383]

1:24 looks like if you had a tube coming from the small tube back to the largest tube it wod flow down hill into it. Perpetual motion?

[@abdulrhman5502]

The water is being "pulled up" by the tube so when it reaches the end there is no force acting on it to make it flow over

[@ektaagarwal9288]

James , make a video on stress strain curve for various materials ....

[@greggiannak5079]

3:39 I like peanuts too

[@msmrzedme]

Pee not 😂

[@_Killkor]

@@msmrzedme Don't pee there

[@bmarkx2595]

*The Action Lab now with mustache*

[@richbarrows3922]

Maybe a hammock is a better analogy for the tension on the surface of the water called Surface Tension. The pressure of air at the surface must be equal to water surface or else there would be a force causing motion.

[@jorisvergeerTBA]

@the action lab, this has nothing to do with pressure. The capillary action happens because water molecules are sticking to the glass tubes and surface tension pulls up more water, bringing more water in contact with the glass, which can then stick to the glass and pulls in even more water. It Goed on until the upward attraction is in equilibrium with gravity. It has nothing to do with pressure. It is more a electrostatic effect. It is more comparible with a magnet pulling up a string of paperclips until the point where the string becomes too heavy and let's go of the magnet. No pressures involved there either.

[@thakyou5005]

With this guy it's like I'm always in school but the difference is this school has only one teacher and it's always fun to learn and he doesn't yell at you if you eat or do anything else while watching / listening lol. Reminds me of the days when I really enjoyed school. One good day would have a lot of talking and interesting subjects which would make the school day so short and I'd be sorry when it would end... ah, good old days. But of course,.most of my school days weren't perfect like that xD.

[@sovietunion6109]

incredible

[@davidpuissegur1263]

Video idea. What does a electrical arc look like in a vacuum ?

[@cygntauri2348]

I like your quarantine mustache

[@melonenlord2723]

As far as i know, forces causes preassure. Normally, a water molecule gets a push from gravitation down and acellerates it. Are there other molecules in the way, instead of accelerating, it passes an impuls that is known as peassure, that pushs the next molecules down, which then also acellerates from this impuls and from its own gravitation force together. So the impuls from the molecules before adds the peassure up while they passes them on to the next down to the bottom. Air is a bit different but in the result it's pretty much the same. Now a capillar causes a force upwards against gravitation in this case. So the amount of peassure that adds up to the bottom gets less and at the point, where the tubes are connected, there is a peassure difference, that causes the water to flow into the smaller capillar and by that, it rises the water level up until preassure gets the same. We know that in the end in the capillar, water doesn't rise or decrease, so forces has to be canceled out. The extra amount of water above the water levels of the bigger capillar causes extra force downwards by gravitation that equals out the force of the capillar effect in this case. That means at the surface of water in the vacuum chamber, there is zero force and so zero preassure. Out of the vacuum chamber the air adds some preassure, that the water can pass on. The peassure difference is very low so there is not really much difference we can see. In that direction a molecul gets pushed it creates preassure, so how it could do less than nothing and does negative preassure? This thouth came from the forst video, where was assumed, that same height means same preassure, so it has to be less peassure when water level is higher up that it would by 1 atm and so it has to be less than 1 atm, but it is still the same on all surfaces, it's adding up less fast down the tube so at the end it's equal. Dont know the distribution of the capillar force, if it's fast adding up, so peassure becomes equally by same height pretty fast it's different until the bottom part of the tube, but as far as i think, it works without negative absolut preassure.

[@melonenlord2723]

because my explanations are weird sometimes, here a sketch: s12.directupload.net/images/200502/2t2p5vw4.png But i really dont know, how the capillar effect is distributet inside the pipe. First makes sense somehow, because in the last video, after the pipes got emptied, they got stuck on the bottom. Same preassur, so now flow there, but the bottom also becomes the top if nothing else is there that isn't effected by the capillar effect, so nearly all could be right.

[@PlagueVamp]

You have a Mario mustache. Keep it, it's cool!

[@MaghrebProductions]

Me before watching the video: there’s no negative absolute pressure as a concept. He must have meant negative relative pressure.

[@duartecastro623]

Laws of physics: exist Action lab: im about to this mens whole career

[@binashah3106]

you misses 'end'

[@fractalnomics]

Like negative prices (and interest rates) Crazy shit.

[@gabrielphilips6980]

Would this also be possible if the tube was made of hydrophobic material?

[@anaveragemcgamer9548]

Here’s a suggestion see if you could swim in other liquids like you can in water

[@Jinnuksuk]

Friendly tip: place your ads where we don't wanna see what happens next in your video. I pay no attention to most ads because they interfere with my mind flow... If what I'm watching has moments where a breather would be nice, I wouldn't mind ads as much.

[@aryangupta7982]

Can you freeze something to -273 C what will negative volume will look alike

[@ShaunVillafana]

Oh so, making black holes are we? Sounds good. Just got my vacuum pump and I'm ready to go

[@noob_machine_696]

Can you show an experiment for this 7:05 the pulling the water part

[@PMX]

In this video, capillary force is also shown in the form of a mustache

[@specialagentdalecooper5367]

8:03 me when I take off my glasses

[@michaelroditis1952]

One more physics problem solved with the vacuum!!

[@mariodistefano2973]

Can you explain why is not possible to have a similar equipment, but with the smallest diameter capillary tube bent just under the maximum height, into the biggest tube, and have so the water flowing again into the main tube, so realizing an infinite flow motion of fluid? If course I know it's impossibile, but would be funny to see what happens... :-)

[@craigslist6988]

I know this is two years old but I'm so shocked that people could have been watching this for two years not understanding this... There isn't a negative pressure in the tube. In your example the tube would fill entirely then stop. The force pulling the liquid up is the attraction of the fluid to the walls. When the tube opens to the main tube there is no more attractive force pulling it further, going further would actually mean moving away from the tube, so it will stop. If there were zero energy losses in the system (there always are, that's 2nd law), the water might continue flowing like you imagine, but you don't need a capillary tube to see that, it's called a Heron's Fountain. And it is not a perpetual motion machine for the same reason.

[@h7opolo]

so your experiment would be nullified by application of a hydrophobic material such as the product NeverWet. 8:18

[@yonatanandreas]

Well 9:39

[@h7opolo]

mercury is a liquid metal and does not fill the microscopic crevices within the glass tube due to atomic size, thus it can't fill the crevices and use surface tension to pull up more water which is a self-reinforcing effect until equilibrium is reached. So, your comment is a gross concept error, troll.

[@agentx7138]

How about a similar experiment but with two sheets of glass touching on one side and separated at the other about an inch so that capillary forces are gradually increased across the apparatus. I would expect to see a nice curve. How far can the liquid rise? And what liquid will rise the most or least?

[@ricknotroll7364]

If there is vantablack on a sheet of paper and nothing on the other side does light still travel through it?

[@davidbergmann8948]

Moustache 🐻

[@randomuser2461]

P. Yes, that is a good variable to describe unknown liquids.

[@randomuser2461]

You don't actually know one P is lower than the other. You are assuming a simple linear correlation then saying it must be under those circumstances. Anything past that and that can vary.

[@sbala_23]

Sir i noticed your t-shirt is awesome 👍

[@KWifler]

So if the little tube was cane shaped, could the water flow out of it? If the water could flow out, could it be directed back into the bigger tube? Then wouldn't you get an imbalance of forces that you can harness to do work?

[@shubhamsingh3519]

A black hole can be made with anything that has energy , as mass and energy are equivalent So with pressure we can make a black hole Similarly with negative pressure can we make negative mass or negative black hole?

[@bitnertinkers]

Could you create constant flow on weightless environments

[@darekk7771]

What if the glass tube was waterproof on the inside? Will water still climb up?

[@ryanthomas2374]

i just want to know where i can get that glass apparatus..

[@justincoleman9776]

Ummm. So you're saying that fluids flow from low to high pressure? P0 is a higher pressure than P1, yet the fluid flows away from P1? Either every physicist is wrong, or there's a major flaw in your explanation.

[@TheActionLab]

justin coleman huh? The flow pushes water from po to p1. From high to low.

[@justincoleman9776]

At about 2 minutes in, you explain the pressure differences. The pressure inside the tube and outside is P0, the pressure just under the tube is P1, and P0 > P1. You say that the atm. pressure is the same inside and out, but the fluid still rises up the tube, toward a higher pressure. If the atm. pressure inside the tube drops (for some odd reason), then its no longer P0.

[@ilhandurmus]

And in your drawing water will have cool evaporation due to low pressure so at the end pressure will be again normal by time because water will be in gas form

[@JackieAu]

47 views, I’m so early

[@holycow666]

I was so early that there was a negative number of views here!

[@Zeldaschampion]

I think he needs to create a negative mustache on that face.

[@The.Plague]

Mustache? Oh, I thought a caterpillar had crawled onto his upper lip.

[@Arch88ch]

3, 2, 1, black hole created successfully

[@jonathannadeau6218]

Vodka in a small glass forms the same meniscus shape but it can’t be from pressure difference.

[@狂人实验室]

非常不错的视频

[@ThatGuy-sd3zl]

I’m going to do the impossible. Proceeds to explain how it’s possible.

[@curtweisflog1567]

JUST A QUICK QUESTION FOR YOU....SPACE IS - 13 ? HOW LOW WOULD THIS VACUUM HAVE TO BE TO BRAKE? FOR SPACE TO TARE HOW LOW WOULD IT HAVE TO GET?

[@prathameshdeshmukh9530]

Hello too everyone reading this comment. You are smart and hope you have a great day :)

[@doublestuffori1703]

thanks, check out my youtube?

[@FedeG86]

Thank you from my part. 👍

[@beachboardfan9544]

Is his mustache crooked, or is the hair on his right just a lighter color?

[@TheActionLab]

Beach&BoardFan-what if it’s both???

[@beachboardfan9544]

😆

[@Pope_Protein]

Hi action lab , just wondering if you remember me a few years ago when I was in hospital :)

[@thakyou5005]

hmmm what's this about?

[@garrettmandujano2996]

Sound at 9:03 sounds like a bubble popping

[@fabiansanchez7203]

Is it really negative pressure tho? Or is it just the stickiness of the water holding itself in place

[@paramountx]

Can you talk about using negative pressure to power a car

[@ilhandurmus]

Negative pressure even extreme negative pressure is even possible with open cups or bottle or aquarium.. or even flat surface it’s not very hard :) just you make induction cooling

[@ilhandurmus]

@@Owen_loves_Butters no even gasses but off course gas will become liquid due to extreme negative pressure but if we make inside tube both side open very extreme negative pressure and with ventilation if we push it to one side gas pass through extreme negative pressure will leave the tube cold and if we make another tube with positive pressure and put between them ventilation from negative to positive pressure we Will have lifting capacity will work even upper altitudes of atmosphere even there is no thick air .. all we need is high speed RMF

[@wastelesslearning1245]

So I guess buoyancy can’t happen in sub pressure liquids?

[@VibratorySix8]

Nice moustache