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

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Formation of vortices in superconductors

So I'm trying to understand how mixed state of a type II superconductor becomes the energetically favourable state. I've been through a simple approximate calculation considering a S-N boundary to ...
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67 views

Surface tension & capillary action

While deriving the equation of height to which the fluid rises, we say that the surface tension pulls the water till the weight of water balances it, my doubt is that how can any force pull on ...
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Should cohesion be considered as a resistant force here?

In some droplet generators, a pressure pulse is applied on top of a liquid reservoir connected to a nozzle and FIRST, a liquid jet is emerged from the nozzle and THEN, pinch-off of a droplet will ...
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12k 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, ...
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1answer
72 views

Why does water remain as a “hemispherical bubble” when it falls on a page?

Today while drinking water, a drop of it accidentally felt on a page of my book, and I was thinking that, "Oh my god! The water will spread instantly, making the part of page wet". But, I observed, ...
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1answer
156 views

Turbulent and smooth flow of water from a tap

When water flows normally from a tap, we can say it is turbulent ( Pic 1 ). But when we attach a piece of cloth to the opening of tap, water flow becomes smooth ( Pic 2 ). We can say that by touching ...
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72 views

What is the surface tension of liquids in space?

I mean does surface tension exists in space on liquids? Let's take an example if I have to write something using ballpen in space and space does not have gravity. Does it works because of the surface ...
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2answers
186 views

Surface tension and capillary rise

The expression for the height rise in a capillary tube is well known, and the surface tension of the liquid air interface is involved. But as I understand the adhesion force between the water and ...
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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: Notice: This is a cork ball attracted to sides of a glass of water
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2answers
457 views

How come a cork float to the side of a glass? [duplicate]

There's a not-so-recent video by a user named quirkology here, where he shows bets that usually work. From @2:19, he puts a wine bottle cap at the center of a glass ...
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26 views

How can I estimate meniscus height and surface area of liquid metal in a crucible at high temperatures?

Is there any methods that can estimate the height of meniscus or the surface area of liquid (liquid metal) in terms of temperature, pressure, viscosities of liquid and contacting gas, and the ...
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3answers
121 views

Coffee Straw Physics

When I put my little, cylindrical coffee straw into my coffee, the liquid immediately rises about half a centimeter up the straw without provocation. This is also the amount of coffee that the surface ...
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1answer
231 views

Why is Surface film a stretched membrane due to surface tension

Surface tension is the property of liquid at rest by virtue of which the liquid surface tends to occupy minimum surface area and behave like a stretched membrane. If surface tension is property ...
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83 views

Why small droplet goes upward after pinch-off?

This small droplet moves against gravity. How to calculate its initial upward velocity exactly after pinch-off?
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1answer
57 views

If the surface tension is reduced to half(say by using a surfactant), what would be the effect on the size of an air bubble in the liquid

If I reduce the surface tension to half of the original value, what would be the effect on the size of an air bubble in the fluid? What would be the effect on buoyancy and drag forces? Also, if I ...
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2answers
136 views

Can a fruit fly move through a large bubble without popping it?

Assume what logistics you need to in order for something like this to be possible. Can a fruit fly move through a large bubble without popping it?
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2answers
393 views

Why is raindrop spherical in shape? [duplicate]

As the topic suggests why the raindrop is spherical in shape? Why it is not triangular or bipyramidal or tetrahedral? Is centre of mass or density of water related to it?
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2answers
48 views

When drying paint brushes washed with water, which way is the best to orient them?

After washing my paint brushes with soap and water and rinsing them, in order to avoid damage to the bristles and the ferrules and the wooden handle, is it best to hang them bristles down and let ...
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1answer
61 views

Does buoyancy change on smaller scales?

For baseball size objects on the order of centimeters across we have experience with what floats and what doesn't. A stick will float and a rock will not. But what if the rock were a grain of sand? ...
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3answers
837 views

Why does a pitcher with lemon juice have foam, while one with pure water does not?

Whenever I pour water into lemon juice (pouring directly from the tap into the pitcher, not quietly along its edge) I get a foam on top: The same pitcher with water (same water tap, pitcher, time ...
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1answer
508 views

What is the cause of the surface tension of the liquids? [duplicate]

What is the cause of the surface tension of the liquids? How to know the direction of tension force on the free surface of the liquid? I know that the surface tension is the force acting normally ...
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0answers
63 views

Can a liquid in a tube have a contact angle of 0 or 180 degrees with the tube?

When a liquid is placed in a tube, it makes contact with the solid walls and has a contact angle (the angle between the tangent to the liquid surface and the wall). What does it mean for the contact ...
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1answer
68 views

When metal solidified, why is its surface not flat like polished?

I expect that what one can see on the outside of a just solidified piece of metal is just the "raw" surface of the inner stucture. Solidifying metals or alloys arranges in partial christal latices ...
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Is surface tension the result of a pressure drop over the air-water interface or visa versa, for a two sphere system?

For a liquid bridge between two spheres the Young-Laplace equation states that: $\vartriangle p= \gamma\bigl(\frac{1}{R_1}+\frac{1}{R_2}\bigr)$ where $\vartriangle p$ is the capillary pressure ...
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1answer
211 views

Difference in electrons excitation in Au (111) between perpendicular and diagonal orientation?

In Au (111) single crystalline as shown in attached file, is there a difference the way electrons are excited when they are excited from perpendicular and diagonal orientation as shown in the figure ...
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Does wetting of fabric surfaces depend on the microscopic surface structure?

I am trying to coat a polymer fabric with a metal alloy by dipping it into the molten metal. (For example a polyamide like Nylon in eutectic Bi/Sn alloy at 138°C , as in Wetting the surface for ...
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66 views

Wetting the surface for soaking Nylon fabric in metal

I'm trying to create metal covered lace. My sister would use it as an artistic material. An interesting material A relevant point is that the mechanical rigidity of the metal is used, so it is not ...
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3answers
363 views

Size of a glass capillary for noticable capillary action

How big would a glass capillary have to be to have noticable capillary action? Also, does capillary action happen in plastic tubes?
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3answers
208 views

Meniscus attached to an inclined plate

To be more specific, suppose a hydrophilic infinite plate is stuck into a semi-infinite region of water, above the water is a semi-infinite region of air, when the plate is stuck into the water ...
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1answer
178 views

How does this capillary-action setup not become a perpetual motion machine?

If you have a very thin glass tube and you place it into water, let's say the water in the tube rises to the height of $x$ mm from the surface of the water. What would happen if you poked a hole in ...
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1answer
59 views

The shape of a bubble? [duplicate]

I have always wondered about a shape of a soap bubble. Why is it always spherical and not some other shape (like, cylindrical)? And why are the layers of the soap bubbles so thin? Also when someone ...
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2answers
250 views

Calculation of tension in a loop with force acting outwards

I'm having a few problems with understanding how to calculate tension in a loop. If I have a circular loop, and some force is applied uniformly radially outwards in such a way that the force acting ...
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1answer
350 views

Capillary action meniscus height in a tube fitted inside another tube?

I was thinking about how would capillary action change in a tube (classic example) and in a tube fitted inside another tube (considering water as the liquid involved). Height of liquid column: ...
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1answer
89 views

Does the value of Surface tension (the value of the constant) change with a change in surface area?

Surface Tension or ϒ (as in gamma) is a constant value for a particular fluid in fixed conditions. When we increase the surface area of the interface, more molecules pop up at the surface and ...
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Fluid flowing into small pores

I have some open porous foams with pore sizes ranging from 50-100nm. I want to flow water into this structure but even at 30 atmospheres it would NOT go in. I am looking for a way to calculate the ...
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1answer
160 views

Wavy stream of liquid

When pouring a liquid into a glass some streams have a wavy shape, like the one in the following photo: (Couldn't find a better picture, sorry.) What causes the stream to be of such a shape?
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2answers
309 views

Why pouring milk from a height makes a chain shape? [duplicate]

I have noticed a chain-like shape when milk is poured from a height into a cup. Actually the chain pattern repeats itself after some distance and again till it reaches the milk in the cup. Any ...
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2answers
164 views

How to find the maximum area of a slot that can keep water in a trough by surface tension?

Assume I have a trough of water 5mm deep. If I cut a slot (oval) into that trough what is the maximum size/area (length x width) that slot can be without leaking? This question is similar to Max. ...
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1answer
57 views

Does the contact angle of a drop depend theoretically on the size of the drop?

According to Wikipedia, contact angle depends on the hydrophobicity of the surface and on thermodynamic equilibrium. But how does it in theory depend on the drop size? In other words, how would a ...
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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 ...
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Thermodynamic quantities of thin soap film on wire frame

Here is a question I am trying to solve. Sorry for the highlighting, it is not relevant. Here are my answers. For a), I would write $dE = dQ + dW$, following the first principle of thermodynamics. ...
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1answer
635 views

Why can liquid mercury sit on salt?

A video shows liquid mercury sitting on top of table salt. Even though the mercury is much denser, it does not sink to the bottom. Why does this happen? Is the mercury just so thick that it is like ...
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3answers
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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 ...
3
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2answers
178 views

What is the maximum net force of surface tension per gram of water?

I've always wondered how much force water exerted through surface tension. By maximum I mean the theoretical pulling/attracting power. Also, what would happen if you raised or lowered the power? ...
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1answer
81 views

Change in radius of a charged bubble

I was thinking about what'd happen to the radius of a bubble, if a charge is uniformly distributed over it. At the beginning, I thought that the bubble would expand, for sure, because of the ...
6
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2answers
163 views

Foam patterns on espresso

When just prepared, an espresso has a thin layer of foam, known as crema, on its surface. As I move my drink from the bar to a table, the motion destroys the homogeneity of the layer, but I've noticed ...
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4answers
9k views

Why is the pressure inside a soap bubble higher than outside?

Apparently, the air inside a soap bubble is under higher pressure than the surrounding air. This is for instance apparent in the sound bubbles make when they burst. Why is the pressure inside the ...
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1answer
166 views

Rate of Dripping of tube

My original problem was to discover the rate at which leaking taps dripped, and its relation with the tap's size, radius, etc. However, I have no clue how taps work, so I simplified the problem. ...
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3answers
114 views

Walking on water

I was wondering about walking on water. I wonder if we can use surface tension to do this. Lets say I make a pair of shoes in shape which has infinite perimeter (e.g a koch snowflake) with glass. Now ...
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4answers
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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 ...