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Questions tagged [capillary-action]

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Meniscus and capillary surface

Can anybody explain what the difference between capillary meniscus and capillary surface?
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Capillary action

I've learnt that capillary action is caused by forces acting on molecules near the interface between solids, liquids (and gasses as well). But there are few things I don't understand. Imagine we ...
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Determining the height of water level rise in a combined capillary tube

What will happen when we fix another capillary tube upon a capillary tube which has not enough space to its free capillary elevation?
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Does capillary rise violate hydrostatic paradox?

If $p$ is a pressure and $p_A = p_{\text{atm}} + hdg,\,$ $p_B = p_{\text{atm}}$, is hydrostatic paradox violated, shouldn't $p_A=p_B$?
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Measure static pressure with measuring tubes of different diameter

Assume you have a horizontally placed cylindrical pipe with constant diameter. There is a flow of water, through this pipe. You want to measure the static pressure inside the tube, which should be the ...
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Derivation of height of a liquid in a capillary tube

I was going through the derivation of height of a liquid in a capillary tube when I came up with a doubt...although its a very basic doubt and you may laugh at it...but please help me...I was thinking ...
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On inserting a thin capillary tube into a large tray of water, does the total surface energy and the total potential energy of the system increase?

In both cases, the system is the liquid in the (tray+tube). I have made reasonably accurate calculations for the gravitational potential energy part. It follows from the calculations that the ...
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Why does liquid rise to same level in these different capillaries?

I'm having a doubt in the two types of approaches used to calculate the liquid rise in capillaries- one by the excess pressure method and the other by balancing weight of fluid column by the forces ...
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118 views

How fast does liquid rise in a capillary tube?

Take a small diameter tube, stick it in water, and surface tension will drive the fluid up through the tube. How fast is the fluid moving through the tube during this process? Here's my attempt: ...
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Curvature of fluid surface next to a floating sphere

I want to estimate the curvature $\kappa$ of the fluid surface next to a floating sphere. The situation is static and shown here: The fluid density is $\rho$, downward gravity is $g$, sphere radius ...
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1answer
67 views

Capillary length and Bond number confusion

The Bond number represents the ratio of gravity forces to surface tension forces, and is defined as $$ Bo = \frac{\rho g L^2}{\sigma}$$ where $\rho$ is the fluid density, $g$ is gravitational ...
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1answer
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Will water spill out of filled capillary tube, if raised from water?

if to raise a filled capillary tube from the level of water, will the inside will spill out? or will it keep stuck inside? imagine a capillary tube put in water, the water rises inside the capillary ...
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Laplace pressure of a capillary bridge

Laplace pressure is given by $$\Delta p=\gamma \left(\frac{1}{R}+\frac{1}{R'}\right)$$ where $R$ and $R'$ are the radii of the curvature of the surface. Using the following diagram the book I'm ...
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Capillary force to move a mobile glass rod

Visualise a glass rod bent to form three sides of a rectangle. A second rod, free to roll on the two parallel sides on the rectangle, constitutes a fourth side of length l. If the apparatus is dipped ...
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Why does a fountain pen soak ink automatically at times?

I've had a rather interesting fascination with fountain pens. The mechanism is a thing of beauty, but my attention was recently caught by a rather insignificant phenomenon which I've used a lot in my ...
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2answers
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Why does water hold up between the teeth of my comb?

Image for reference: As can be seen in the above image, whenever my comb comes in contact with water, a little of it is trapped between the teeth. This happens whether I dip it in still water or ...
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68 views

Does molten solder flow towards a heat source?

When soldering both plumbing and wiring I have heard the advice that you shoulf apply solid solder opposite to your heat source, since the solder "will flow towards the heat" once it melts. Is this a ...
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The vertical component of surface tensions in wetting

To find the contact angle made by a droplet on a flat surface at equilibrium, we take the sum of all surface tensions at the boundary of the droplet to be equal to zero (Wikipedia link). Projecting ...
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119 views

How do honeycomb humidifier wicks soak up water?

I'm trying to figure out how I can make my own humidifier filter/wicks since all the commercial ones seem to be treated with antibacterial chemicals that I don't want to breathe. I thought I would be ...
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Is Pascal's law incorrect?

Consider the figure given below. Here I'm gonna talk about capillarity. The liquid inside the beaker as well as the column is water. As water has a tendency to rise in the capillary as shown, doesn't ...
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Can water drip from a capillary tube top? Perpetual motion?

In a normal capillary tube (ex: tube A), where the water doesn't travel as high as the tube's height, h, the meniscus formed is "normal" (concave, as seen in tube A). From previous posts, I ...
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Capillary Perpetual Motion

Can anyone figure out what is wrong with this perpetual motion machine? What part of it violates physics? I found it on a website a while ago, and I couldn't figure out what was wrong with it. Thanks, ...
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Capillary tube and mercury going up

My question is quite straight forward: What forces are pushing mercury up a capillary tube and then preventing it from going higher as tube gets thinner? Setup: We've got a container filled with ...
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162 views

Capillary action in different tube diameters with mercury

Imagine we put two glass tubes in a container bulged with mercury. These tubes have 2 radii which we call them : 1.Big 2.Small The height of mercury column in the big one is more than the small one. ...
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Water movement in variable diameter bent capillary?

So, I recently learned that if a capillary tube is bent in an upside down U shape, the meniscus formed will be convex (towards the ground). Furthermore, the height (shown as h) traveled by the water ...
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Meniscus in U-shaped capillary?

What does the meniscus look like for a U-shaped capillary? From similar questions, I learned that the total height (labeled as h) reached by the water in the un-bent capillary is less than the total ...
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Is calculating the capillary pressure by surface area always equivalent to calculating with the radii of curvature?

The typical method for calculating the capillary pressure of a cross section is to use the following equation: $P_c = \sigma (\frac{1}{R_1} + \frac{1}{R_2})$ Where $R_1$ and $R_2$ are the radii of ...
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Why is the critical seperation distance between two plates for capillary condenstation to occur negative?

I am currently reading this paper: Auto-adhesion model for MEMS surfaces taking into account the effect of surface roughness Can be found here: https://www.spiedigitallibrary.org/conference-...
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Doubt in capillary rise

The capillary action formula is given as: $$h=2T/ρgR$$ where h is the capillary rise, R is the radius of curvature of miniscus, ρ is density, g is force of gravity and T is the surface tension. Now ...
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Concept of contact angle, cohesive and adhesive forces

I was reading the topic of contact angle from a book and I couldn't exactly understand it. The first photo depicts the general case when a solid surface touches a liquid surface. $Fs$ is the adhesive ...
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529 views

Capillary Rise and a Surfactant - Experiment

Proposed Experiment: Consider a capillary tube, dipped in a container filled with water (Assume that the tube doesn't topple over or sink, it is fixed in its position somehow). It is obvious that we ...
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Capillary being pulled out of a large reservoir

For the above question, they've equated the excess pressure across the meniscus to the pressure due to height of liquid column in the capillary, as follows: This clearly gives RH = constant, hence ...
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1answer
306 views

Height In a Tilted Cappilary tube

If we tilt a cappiliary tube, i had the doubt that would the height rise of fluid change change..? If not why.. and if it would how may we proceed to find the change? I have assumed the condition to ...
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Can particles be sucked into a pipe while water is pushed through it

The picture below shows a piece of equipment dentists use, called a "water scaler". As you can see, there's water spraying out of it through a very small hole right in front of the bend. I've been ...
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In derivation of capillary rise we take the upwards pressure as 2T/r…How?

In derivation of capillary rise will take Texas pressure due to surface tension in upward direction as 2T/r...Can some please explain how did this came
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What will happen if I break a raised capillary tube?

Suppose I have a capillary tube inside a water trough and water level raises inside the tube till point 'x'.Now if I break the tube below this level 'x', will the water keep on flowing forever because ...
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174 views

Capillary action in the presence of pin holes

Assume that capillary forces are sufficient to draw a fluid up a tube. Now repeat the experiment with very tiny pin-holes in the tube. The question: do the pin-holes limit the capillary action? Or ...
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Frequency of water droplets from capillary

I would like to determine the drop formation frequency of water dripping from a capillary tube of some radius. I know I can calculate the mass of each droplet by looking at the relations between the ...
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257 views

Physics of dunking biscuits

Together with my 5 years old assistant, after endless observations breakfast after breakfast, we finally decided to be serious about it, and quantify a remarkable property of biscuits in milk. ...
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Does folding a paper towel help dry your hands faster by creating interstitial forces?

The question is based on a TEDx video, where the speaker claims that folding a paper towel before using it creates interstitial forces which help dry your hands faster. The question: Does this ...
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349 views

Effect of acceleration on rise of liquid in capillary

What would be the effect of vertical acceleration on the rise of liquid level in a capillary tube. Will the liquid not rise if we provide the system a downward acceleration equal to $g$ ? Consider ...
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Conservation of Energy in Capillary Tube

The capillary action lets a liquid rise in a narrow tube to a certain height. In this, the liquid gains some potential energy. According to the Conservation of Energy, the energy must come from ...
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Why would water rise if the height of the capillary tube above the water surface is decreased?

While studying fluid mechanics I came across a section which say: If a tube is submerged in water and some part is empty Water rises in a capillary tube say to height $ h$ .Now changing the length ...
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Can a capillary opening lift a huge load?

The problem I pose is about an application of the Pascal law and capillary action. It is based on a plot which I describe hereafter. Imagine a one side sealed cylinder with a piston on the other side....
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88 views

Diameter Shifting Capillary Tubes

Is there any known material of which to construct a capillary tube that would make it possible to compress the diameter of the capillary tube while maintaining the internal shape? Intent being that ...
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Why is the angle of contact different for a meniscus and a droplet in the same water/glass/air environment?

There's gravity, there's adhesive and cohesive attractive forces. Fair enough, most materials seem to compare water to mercury in capillary tubes when explaining capillary action and above properties ...
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Contact Angle In Capillary

One Professor recently told me that in an insufficient length capillary, the contact angle doesn't change, its an inherent property which does not change. If the edges of capillary are extremely sharp ...
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Bent capillary tube

What would happen if I bend a capillary tube and use it as shown in figure? 1.Will the water(or any other adhesive liquid) level remain same as before bending? 2.or it will come up till end? 3.Or ...
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1answer
3k views

How does capillary action work in tubes which are closed at the top?

In all textbooks the examples and descriptions use tubes which are open at both ends. Our teacher remarked that if it were closed at one end like a test tube (albeit a thin one) even then capillary ...
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percolation permeability threshold in Helium before and after lambda point transition

There's an experiment demonstrating the properties of super-fluid Helium compared to normal fluid Helium, in which the Helium is put in a jar who's bottom is porous. The super-fluid can pass through ...