Questions tagged [capillary-action]

The tag has no usage guidance.

Filter by
Sorted by
Tagged with
2
votes
1answer
48 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{...
0
votes
0answers
28 views

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 ...
5
votes
0answers
461 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 ...
3
votes
2answers
159 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 ...
1
vote
1answer
224 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 ...
1
vote
1answer
238 views

Capillary turned upside down

I have a glass capillary filled with water at half volume. The meniscus shape is well known. I turn the capillary upside down. The water does not flow out. What shape the new meniscus will be? Roughly....
2
votes
2answers
187 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 ...
1
vote
2answers
1k views

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 ...
5
votes
1answer
414 views

Does gravity affect water permeability?

Suppose I have an approximately rectangular prism composed entirely of folded paper. If I place 600lbs on top of these rectangular sheets of paper, the paper should compress. How does this affect ...
1
vote
1answer
170 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 ...
0
votes
0answers
38 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 ...
0
votes
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 ...
0
votes
1answer
269 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. ...
0
votes
1answer
71 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 ...
0
votes
1answer
175 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 ...
0
votes
2answers
3k views

Capillary action and perpetual motion

From Wikipedia Capillary Action Thus for a 4 m diameter glass tube in lab conditions given above (radius 2 m), the water would rise an unnoticeable 0.007 mm. However, for a 4 cm diameter tube (radius ...
8
votes
2answers
670 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 ...
5
votes
4answers
4k views

Why doesn't this capillary action generator work?

So I was doing a bit of reading. Apparently the obstacle to generating energy from the forces driving capillary action is breaking the surface tension at the top of a capillary tube. It is just ...
0
votes
2answers
12k 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?
0
votes
1answer
44 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 ...
0
votes
0answers
13 views

Meniscus and capillary surface

Can anybody explain what the difference between capillary meniscus and capillary surface?
0
votes
1answer
280 views

Direction of surface tension

consider the capillary tube shown in the diagram. According to my book the direction of surface at the point of contact is towards the surface as in diagram 2, but shouldn't it be away from as in ...
0
votes
1answer
41 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 ...
0
votes
0answers
60 views

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?
9
votes
2answers
821 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 $p_A=p_B$?
0
votes
0answers
70 views

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 ...
10
votes
1answer
691 views

Sandstone getting soaked with water [duplicate]

I have seen someone putting a sandstone in water. With only about 10% of the stone sitting in the water. One could see the stone getting soaked with water. So there must be a force, which lets the ...
0
votes
1answer
64 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 ...
0
votes
0answers
78 views

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 ...
1
vote
1answer
421 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, ...
1
vote
0answers
63 views

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 ...
4
votes
1answer
254 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: ...
0
votes
1answer
52 views

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 ...
10
votes
2answers
5k views

How is the water meniscus at the edge of a capillary tube?

Suppose we have a capillary tube in which water can rise to a height of x cm. If we dip the tube such that the height above the surface is less than x, then how will the water meniscus be at the edge ...
1
vote
1answer
35 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 ...
0
votes
1answer
281 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 ...
0
votes
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 ...
1
vote
2answers
90 views

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 ...
4
votes
2answers
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 ...
0
votes
1answer
894 views

Absorption of Water

I was just watching the videos Chris Hadfield put on youtube from space, and was wondering why water doesn't get absorbed as well onto his toothbrush in space? And what characteristic of toothbrushes ...
0
votes
2answers
50 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 ...
4
votes
1answer
279 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 ...
1
vote
2answers
2k views

Capillary engine is impossible?

I read some articles saying that it is not obvious (or maybe impossible) to generate energy using capillary action. On the other hand in my understanding trees uses capillary action to extract water ...
1
vote
0answers
186 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 ...
2
votes
1answer
343 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 ...
4
votes
1answer
785 views

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 ...
1
vote
0answers
47 views

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-...
5
votes
7answers
17k views

Capillary tube of insufficient length

I was wondering if we have a very thin glass tube placed in a tub of liquid and the portion of the tube outside the liquid is lesser than the height to which the liquid can rise because of capillarity,...
1
vote
4answers
839 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 ...
3
votes
1answer
2k views

Can capillary forces be used to make hydro electricity?

Could a device with very thin columns of glass or something that attracts water more be used to pull water up and then release it to drive generator and perhaps add vacuum. I have been wondering ...