Surface tension occurs due to the tendency of liquid molecules to favor their own kind. Surface tension is important in fluid multiphase systems typically at small length and velocity

learn more… | top users | synonyms (1)

0
votes
2answers
25 views

What is the effect of surface tension on an air bubble inside water?

When an air bubble is formed inside water, and while it's still inside, does a force due to surface tension act on it? Why and where does this force act? I read somewhere that a bubble would detach ...
2
votes
1answer
34 views

Evolution of minimization of surface tension

What are governing equations (or/and variational principles) for evolution of a simply connected body of water in vacuum? Initial state - for time $t=0$ we have a bounded simply connected set ...
1
vote
1answer
27 views

Modeling Water Surface Impact

I have a project that is to model the wave equation in a pond due to a pebble being thrown in. The project is quite simple as all we really have to model is the wave equation with an initial ...
0
votes
0answers
22 views

Electrostatic pressure and charge [closed]

I've become a bit stuck on a question involving the charge transferred to a soap bubble as it's momentarilly connected to a potential V. I calculated the pressure difference between the atmosphere ...
9
votes
4answers
453 views

Why does string not wick down?

I regularly drink tea at work and I often reuse the tea bags (yes I know I'm a cheapskate). Yesterday afternoon I used a tea bag once and kept it in the cup in case I wanted another cup before I ...
2
votes
1answer
51 views

Time taken in changing surface tension [closed]

I had read some where that the water in glasses has a high surface tension, but in lota (It is sort of a spherical container) the surface tension is lower. How can I measure the water surface ...
7
votes
2answers
425 views

How much of the forces when entering water is related to surface tension?

When an object enters water with high velocity, (like in Why is jumping into water from high altitude fatal?), most of it's kinetic energy will be converted, eg to accelerate water, deform the object ...
1
vote
1answer
31 views

Relationship between existence of forces on a liquid surface, and the tendency to decrease the surface area

What does the following sentence imply? "Because of the existence of forces across any line in the surface of a liquid, the surface tends to shrink whenever it gets a chance to do so." Why does the ...
5
votes
1answer
331 views

Lotus effect dust removal

I have found hundreds of papers describing the contact angle of water droplet sitting on hydrophobic surface and the change between Wenzel Regime and the Cassie-Baxter regime. Now, as I understand ...
0
votes
1answer
23 views

Measuring cross-section area of a flexible tube (5mm dia approx)

I want to measure the avg. inner cross-section area of a flexible tube of outer diameter 5mm. Since the cross-section isn't a circle exactly, use of vernier caliper to measure inner diameter fails. ...
7
votes
1answer
1k views

physics of wet hair

I'm curious about the physics behind the clumping of wet hair. More specifically, how the amount of water in hair and distance between hairs affect the clumping process. I know intuitively that when ...
4
votes
1answer
74 views

Water falling, why does it spin?

I have noticed that water, when falling will rotate. Looking closely at a thin stream from a faucet and placing a flat object mid stream you will see the water is rotating. The further down the stream ...
2
votes
1answer
45 views

How does surface tension enable insects to walk on water?

I understand that water molecules at the surface have a net inward attraction due to the lack of water molecules above them. I've been reading a bunch of articles, and they say that this inward pull ...
2
votes
4answers
71 views

In the formula for the mass of a drop of water on the end of a tube, is r internal or external radius?

In the formula for the mass $m$ of a drop of water forming on the end of a vertical capillary tube, $$m = \frac{2\pi r \gamma}{g},$$ does $r$ refer to the internal or external radius of the ...
1
vote
1answer
35 views

Resource(s) for developing a good understanding of surface tension?

I have read through several junior undergraduate level explanations of surface tension. Here is a typical presentation at that level: Molecules at the surface of a fluid experience approximately ...
4
votes
0answers
54 views

Why do floating objects attract? [duplicate]

Objects floating on the surface of calm water seem to be attracted to one another and tend to come together in a drift. Is this attraction like gravity?
3
votes
0answers
42 views

Why will two bubbles floating on water surface attract each other?

Two identical bubbles floating on water surface will form clumps, according to the "cheerio effect". But what's the detail about the force? It's necessary to calculate the shape of water surface, in ...
3
votes
4answers
762 views

What is the physics behind a soap bubble?

A soap bubble is an extremely thin film of soapy water enclosing air that forms a hollow sphere with an iridescent surface. What fluid dynamical process occurs during the popping of a soap bubble?
4
votes
1answer
44 views

What are circles on broth (eating soup) surface?

Think about broth in the soup, usually it has circles on its surface. What are their properties? Why there are many of them (not a few big blobs)? Are they depended on liquid's temperature? What needs ...
3
votes
2answers
326 views

Why doesn't the water spill out?

In this experiment, a number of coins are put into a cup full of water, without spilling it. http://www.youtube.com/watch?v=N2mKpZHnEzw Firstly, let me clarify one thing. If you fill up a cup ...
3
votes
1answer
110 views

Formation of meniscus

If molecules at the surface of a liquid have higher energy and want to minimise the surface area, then why is a mensicus formed which of course increases the surface area?
1
vote
2answers
86 views

What is a good model for computing water dropping on a surface?

Before introducing my question I would like to outline the fact that I'm a coder, so I can be wrong when using some kind of terminology. What is a good model for computing the flow, the shape and all ...
1
vote
0answers
69 views

Needle Floating on a Water Surface

So, I'm trying to find the largest radius of a needle before it ends up sinking, and I know that it's a balance of needle weight vs surface tension. However, I'm not really sure how the surface ...
4
votes
1answer
99 views

where does the energy of water droplet go?

My experiment: I took a string (3 mm diameter and wet) and a water source (1 drops per 2 seconds). Then I attached the string to the water source. The string was then tied to ground Observation : ...
7
votes
2answers
145 views

Tension in string due to surface tension

Suppose you take a loop of string and place it on the surface of a liquid, the string should become taut due to surface tension. How would you be able to calculate the tension in the loop of string? ...
2
votes
1answer
63 views

Non-determinitric flow of water stream on vertical porcelain surface

I noticed several times while washing my hands that accumulated water when starts streaming vertically does not flow vertically in straight line on vertical porcelain surface under the force of ...
3
votes
2answers
86 views

Why is it tension in surface tension?

Why is it called surface tension not surface compression?
2
votes
2answers
2k views

About an upside down cup of water against atmosphere pressure

There is an experiment we learned from high school that demonstrated how atmosphere pressure worked. Fill a cup of water and put a cardboard on top of it, then turn it upside-down, the water will not ...
1
vote
2answers
376 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 ...
0
votes
1answer
256 views

Problem with ring-method of du Nouy for calculating surface tension

I need to calculate the surface tension of a liquid with the ring-method of du Nouy and the correct formula to use is: $\gamma = \frac{F}{4\pi R}$ I understand that the surface tension is the ...
19
votes
4answers
1k views

Why does a cork float to the side of a glass?

What is this physical phenomenon and when it's happen ? Please take a look at this picture: Link to picture Notice: This is a cork ball attracted to sides of a glass of water
3
votes
2answers
85 views

Does quasi-static motion imply zero energy dissipation?

When a droplet is deposited on a surface with some surface roughness and subsequently tilted it can stick due to pinning (think of droplets on a window after rain). What I am interested in is ...
6
votes
2answers
296 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 ...
5
votes
2answers
291 views

Can water pressure ever be high enough to trap gas bubbles or keep them from surfacing?

Can water pressure ever become high enough to trap gas bubbles and/or keep them from surfacing?
1
vote
1answer
878 views

Problem understanding the capillary action equation

As you know the equation of capillary action id given by: $h=\dfrac{2\gamma\cos\theta}{\rho gr}$ Where: $h$ is the height the liquid is lifted, $\gamma$ is the liquid-air surface ...
4
votes
1answer
925 views

Why does water sometimes form bubbles when I pour it into a glass?

Sometimes when I'm filling up a container with water from the tap, bubbles will form on the top of the water. They look a little like soap sud bubbles, but there's no soap suds present. I notice, ...
1
vote
2answers
167 views

Water doesn't flow above the rim, one reason is surface tension. Is another reason viscosity?

According to Surface tension, water molecule don't get the force from outside and get little bit outward. Is one reason viscosity? Let's look at the water in a fully filled glass. No part is outside ...
4
votes
1answer
89 views

Variational principles: Meniscus

In determining the shape of a meniscus, we have to minimize the energy per unit length along the direction perpendicular to the cross-section of the meniscus: $$\frac{E}{L}=\int^L_0 dx [\gamma ...
15
votes
1answer
187 views

What are the equations of motion of a hole in a soap bubble?

Imagine the following situation: I have a thin stationary water film, like a soap bubble, suspended inside a large ring. I throw a small loop of string onto the film and punch a hole inside it. How ...
5
votes
2answers
727 views

Solving the Young-Laplace equation for arbitrary axisymmetric geometry

Say I have a non-ellipsoidal soap bubble and I want to numerically analyse the pressure in the inner lobe of this bubble here: The Young Laplace equation gives the pressure difference across a ...
6
votes
0answers
216 views

Surface tension between water (liquid) methane (gas)

In my project I should calculate surface tension between water and methane with lammps. I write the program.I use SPC model for water and $l_j$ for methane and water - methane. But now I don't know ...
3
votes
5answers
273 views

How can the surface of a liquid exist if there are no attracting molecules above it?

Okay this is probably a stupid question but here goes: We know that molecules in a liquid are attracted from all the molecules around it so there is no net attraction. Well, then how do the ...
2
votes
1answer
112 views

Why do new towels dry better after a few uses?

Most of you will be familiar with the phenomenon: you have bought a new towel and you first have to wash it or use it a couple of times before it starts to work properly, i.e. dry your body after ...
1
vote
1answer
207 views

Dynamic simulation of surface tension [closed]

Is there any substantial body of work in physics on dynamically simulating effects of surface tension on liquids? The texts i found so far on fluid dynamics all seem to ignore surface tension, ...
0
votes
1answer
63 views

Is there a way to define a function of a meniscus curvate?

If you cut a thin slit in thin opaque material and then put it into water and pull it out, the meniscus will be formed in the slit. For my research I need to know if it is analytically possible to ...
9
votes
3answers
214 views

Surface energy as thermodynamic potential

Consider free energy of sharp interface $\Gamma$ $$ \int_\Gamma \sigma\;\mathrm{d}S $$ or also free energy of diffuse interface of characteristic width $\epsilon$ given by Cahn-Hilliard/Allen-Cahn ...
1
vote
1answer
216 views

Stability and lifetime of soap bubbles formed with light gases like helium or hydrogen?

A friend asked me if it would be possible to make soap bubbles out of a gas like hydrogen and if you did, would they float higher, faster. Due to the lower mass of light gases (compared to the air) I ...
2
votes
1answer
109 views

English/German translation of Latin scientific texts in general, “Principia Generalia Theoriae Figurae Fluidorum in Statu Aequilibrii” in particular

I am trying to get my hands on an English or German translation of the seminal work by Gauss on fluid shapes in equilibrium: "Principia generalia Theoriae Figurae Fluidorum in statu Aequilibrii ...
0
votes
1answer
107 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 ...
4
votes
1answer
301 views

Explanation for breaking up of a stream of water into droplets

Water falling from a tap eventually breaks into droplets at a particular distance from the tap. The distance(from the tap) at which it breaks into droplets is observed to be an increasing function of ...