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# Dataphysics GmbH

## Surface tension Dataphysics GmbH

Mechanics of continuous environments
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Solid Mechanics
Fluid Mechanics
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## The paper clips are standing on the water due to the surface tension.

Surface tension of a drop dripping from milk

Surface tension is a property of liquids that causes their outer layer to act as an elastic sheet.

This is the property that causes two levels of fluid to abduct each other;

Like two drops of water that kidnap each other and make a bigger drop.

Surface tension is a quantity Dataphysics GmbH

that has a force per unit length or energy per unit area and is usually

denoted in physics by display \ displaystyle \ gamma} \ gamma. Surface tension can

also be considered as the amount of work required to create a new joint surface unit.

## Contents

1 cause
2 Show minimum levels with liquid level
3 effects
3.1 capillary effect
3.2 Breaking the flow of liquid to the drop
3.3 Effect of ionic structures on surface tension
3.4 Effect of molecular structures on surface tension
4 surface tension in everyday phenomena
5 Gallery Dataphysics GmbH
6 Related Articles
7 sources
Cause

## Graph the forces applied to two molecules of a liquid.

Each liquid molecule is abducted by other liquid molecules. Molecules inside the volume of the liquid are abducted from all directions and the result of the force applied to them is zero.

But molecules that are on the surface of the liquid are only abducted from one side to the other by the molecules, and the abduction force across the liquid boundary (for example

, from the air molecules) is less to them; Therefore, a pure force is applied to the molecules on the surface of the liquid, which is neutralized by the resistance of the liquid to compression.

As a result, a force is created in the liquid that wants to lower the liquid level. Therefore, the liquid surface acts

as an elastic sheet and shrinks so that it has the lowest possible surface.

Another way to explain surface tension is that if a molecule is next to its neighbor molecule, its energy is less than when it is not next to its neighbor. Internal molecules have the largest

number of possible neighbors; But the molecules on the surface have fewer neighbors and therefore have more energy than the energy of the inner molecules;

### Therefore, Dataphysics GmbH when a liquid wants to

minimize the energy of the straw, it tries to reduce the number of its surface molecules,

which means that a liquid wants to have the lowest possible level.

To reduce the surface area, a liquid always takes the smoothest possible shape on its surface (mathematical proof of why the

smoothest surface corresponds to Dataphysics GmbH the smallest area requires the

Euler-Lagrange theorem). Each new curvature on the surface results in more area and therefore more energy.

In fact, the reason for creating a force-resistant surface on the surface of liquids is the resistance of the liquid to changes in external area

Because the fluid tends to remain at a minimum surface state, another reason is the resistance of the surface molecular forces (van der Waals) to distance from each other.

## Display minimum levels with liquid level

### Minimum level

If we want to find a two-dimensional procedure that falls between certain boundaries and has the lowest possible level, we may find it difficult to come up with mathematics; But instead we can

wire the borders and put it in a container full of soap and water. The layer of soap bubbles that builds up between

the wires almost represents a procedure with the lowest possible surface (if

it were not for th

e gravity of the earth, it would have formed exactly the lowest level). 

Effects
Capillary effect

Show capillary effect for two tubes of different materials. Water adheres more

to the red tube and to the blue tube than the water adheres to itself.
The capillary effect is the rise of the liquid level in the tube that is immersed in the liquid. If the pipe is narrow enough and the water adhere

s to the pipe is high, the surface tensi

on can raise the water in the pipe. The height of the rising water is equal to

display \ displaystyle h \ = \ {\ frac {2 \ gamma _ {\ mathrm {la} cos \ cos \ theta} {\ rho gr}}} display \ dis

playstyle h \ = \ {\ frac {2 \ gamma _ _ \ mathrm {la}} \ cos \ theta {{\ rho gr}}

## where in

display \ displaystyle \ scriptstyle h} display \

displaystyle \ scriptstyle h} The height of the liquid is high.
display \ displaystyle \ scriptstyle \ gamma _ {\ mathrm {la}}}

display \ displaystyle \ scriptstyle \ gamma _ {\ mathrm {la}} سط Surface tension between liquid and container.
display \ displaystyle \ scriptstyle \ rho. display \

displaystyle \ scriptstyle \ rho} is the density of the liquid.
display \ displaystyle \ scriptstyle r} {\ displaystyle \ scriptstyle r} is the capillary tube radius.
display \ displaystyle \

## script

style g. {\ displaystyle \ scriptstyle g است Gravity acceleration.
display \ displaystyle \ scriptstyle \ theta.

display \ displaystyle \ scriptstyle \ theta است The contact angle of the liquid and the surface of the pipe. If display \ displaystyle \ scriptstyle \ theta. Display \ displaystyle \ scriptstyle \ the

ta} is greater than 90 °, like mercury in a glass tube, the liq

uid goes down instead of rising.
Break the liquid flow to the drop

## The middle state of the current that breaks into drops.

The flow of water from the milk drips, no matter how uniform. This is due to a phenomenon called plateau-rail instability,  which is itself a direct consequence of surface tension.

The effect of ionic structures on surface tension

The surface tension of water at zero degrees Celsius is 75.64 dyn / cm,

while the surface tension for a 6M NaCl solution is 82.55 dyn / cm, because the surface tension is actually the result of intermolecular

van der Waals forces, and the stronger these forces, the higher the tension.

The surface also becomes larger. The addition of polar and ionic particles,

such as sodium chloride, to the water causes the attraction between the particles to increase,

because the attraction between the ionic particles and the water molecules is

stronger than the attraction between the water molecules alone, so the surface tension