Questions tagged [capillary-action]

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15 views

Angle of contact in a capillary tube?

Why the angle of contact of water and glass is 0. According to the capillary action why the angle of contact of water and glass is 0.
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79 views

How can a tree fill a coconut with water? [duplicate]

Water goes up in plants by cappilary action. So that should also explain water inside coconuts. My doubt relates to the easy experiment of transfering water from a filled glass to an empty one using ...
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41 views

Why can water wicks act like siphons?

Take two empty cups (cup A and cup B) and fill cup A with water. Take a length of wet cloth and run it from the bottom of cup A to the bottom of cup B, while the cups are standing next to each other ...
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Mechanism behind capillary action

When we place a capillary tube in a beaker containing a liquid, why does the liquid level in the tube rise? Also, if it rises, won't there be a difference in the pressure at points A and B?( A is ...
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173 views

Pressure variation in a capillary tube

The following image shows capillary tubes placed in beakers containing water and mercury: We know that the rise or fall in the level of liquid in a capillary tube is given by Jurin's law: $$h=\frac{...
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Does capillary action affect the accuracy of mercury barometer?

We know that mercury barometers are used to measure the atmospheric pressure by determining the height of mercury in the vertical column. Further, we know that the level of mercury in a capillary tube ...
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45 views

Surface tension and Speed of capillary action

I have read that the height of meniscus in a capillary is directly proportionate to liquid-air surface tension. That left me wondering, is the speed at which capillary action occurs also ...
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2answers
37 views

How to avoid water tension in a hose?

I am doing a project in which I have to flow water between two containers, which are connected at the bottom by a 1/4" hose. Remarkably, the surface water tension is such that water does not flow ...
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1answer
87 views

Why does solder wick absorb solder?

Solder wick is basically just braided copper wire that absorbs molten tin solder in contact. But how does it work? The molten solder is very effectively sucked into the braids. The same effect is not ...
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744 views

How is it possible for tall trees to pull water to heights more than 10m?

Which force actually drives water so high up, since pure atmospheric pressure will only get you up to about 10 meters if you're using suction and a long straw and yet tallest trees are over 100 meters ...
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1answer
71 views

Diameter to prevent water flow into a closed-end tube?

Imagine I drill three holes of different diameter into a large block of plastic but the holes don't go all the way through. (They form three close-ended tubes, see the image.) I then submerge the ...
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Meniscus and capillary surface

Can anybody explain what the difference between capillary meniscus and capillary surface?
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48 views

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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835 views

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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1answer
67 views

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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1answer
324 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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2answers
217 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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2answers
47 views

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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339 views

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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1answer
35 views

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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1answer
200 views

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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203 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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55 views

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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1answer
191 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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1answer
307 views

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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507 views

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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2answers
504 views

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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265 views

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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1answer
299 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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197 views

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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1answer
367 views

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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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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4answers
906 views

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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1answer
179 views

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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786 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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1answer
65 views

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
455 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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88 views

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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13k views

In derivation of capillary rise we take the upwards pressure as $2T/r$. How?

In the derivation of capillary rise, we take excess pressure due to surface tension in upward direction as equal to $2T/r$. Can some one please explain how does this come about?
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469 views

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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1answer
252 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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281 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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2k views

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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469 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 ...