English Deutsch Français Italiano Español Português 繁體中文 Bahasa Indonesia Tiếng Việt ภาษาไทย
All categories

2006-10-07 18:59:07 · 11 answers · asked by kannan 1 in Science & Mathematics Physics

11 answers

A phsycial properties call surface tension.

2006-10-07 19:01:42 · answer #1 · answered by Anonymous · 3 0

All the liquids shows a physical property called "surface tension", which makes the liquids to form a shape which gives lowest possible surface area. As the spherical shape gives the lowest possible surface area, all the liquids droplets form spherical shape

2006-10-08 04:27:05 · answer #2 · answered by Skpin 1 · 0 1

it is due to surface tension
surface tension is a phenomenon in which the liquid tries to have minimum surface area and since the surface area of a sphere is min the drop assumes a spherical surface
if u consider a bucket full of water then the molecules of water inside the bucket have other molecules on each side and hence they experience collisions in all directions but molecule on the surface has an outward force and becomes unbalanced and hence to minimize its potential energy it tends to have minimum area

2006-10-08 03:58:42 · answer #3 · answered by Anonymous · 0 1

Because of surface tension. the water molecules try to minimise the surface area as small as possible, hence a drop of liquid is spherical.

2006-10-08 02:09:54 · answer #4 · answered by St Harpy 6 · 0 1

A drop is a small volume of liquid, bounded completely or almost completely by free surfaces. The simplest way to form a drop is to allow liquid to flow slowly from the lower end of a vertical tube of small diameter. When the pendant drop exceeds a certain size it is no longer stable and detaches itself. Drops may also be formed by the condensation of a supercooled vapor or by atomization of a larger mass of liquid. The weight of the largest drop that can hang from the end of a tube of radius a is nearly

mg = 3πaλcosα

where λ is the surface tension of the liquid and α is the angle of contact with the tube. This relationship is the basis of a convenient method of measuring surface tension.

Due to the different refractive index of water and air, refraction and reflection occur on the surfaces of raindrops, leading to rainbow formation.

Without surface tension, drops would not be able to form. The dimensions and stability of drops are determined by surface tension

In physics, surface tension is an effect within the surface layer of a liquid that causes that layer to behave as an elastic sheet. This effect allows insects (such as the water strider) to walk on water, and causes capillary action. Interface tension is the name of the same effect when it takes place between two liquids.

Surface tension is caused by the attraction between the molecules of the liquid by various intermolecular forces. In the bulk of the liquid each molecule is pulled equally in all directions by neighboring liquid molecules, resulting in a net force of zero. At the surface of the liquid, the molecules are pulled inwards by other molecules deeper inside the liquid but they are not attracted as intensely by the molecules in the neighbouring medium (be it vacuum, air or another liquid). Therefore all of the molecules at the surface are subject to an inward force of molecular attraction which can be balanced only by the resistance of the liquid to compression. Thus the liquid squeezes itself together until it has the locally lowest surface area possible.

Surface tension is represented by the symbol σ, γ or T and is defined as the force along a line of unit length where the force is parallel to the surface but perpendicular to the line. One way to picure this is to imagine a flat soap film bounded on one side by a taut thread of length, L. The thread will be pulled toward the interior of the film by a force equal to γL. Surface tension is therefore measured in newtons per meter (N·m-1), although mN m-1 are normally used.

A better definition of surface tension, in order to treat its thermodynamics, is work done per unit area. As such, in order to increase the surface area of a mass of liquid an amount, δA, a quantity of work, γδA, is needed. Since mechanical systems try to find a state of minimum potential energy, a free droplet of liquid naturally assumes a spherical shape. This is because a sphere has the minimum surface area for a given volume. Therefore surface tension can be also measured in joules per square metre (J·m-2).

The equivalence of both units can be proved by dimensional analysis.

A related quantity is the energy of cohesion, which is the energy released when two bodies of the same liquid become joined by a boundary of unit area. Since this process involves the removal of a unit area of surface from each of the two bodies of liquid, the energy of cohesion is equal to twice the surface energy. A similar concept, the energy of adhesion, applies to two bodies of different liquids. Energy of adhesion is linked to the surface tension of an interface between two liquids.

Surface tension has a big influence on many common phenomena, specially when certain substances, surfactants, are used to decrease it:

Bubbles have very high surface areas for a very small masses. Bubbles can not be formed from pure water because it has a very high surface tension, but the use of surfactants can reduce it more than tenfold, making it very easy to increase its surface area.
Colloids are a type of solution where surface tension is also very important. Oil will not spontaneously mix with water, but the presence of a surfactant provides a decrease in surface tension that allows the formation of small droplets of oil in the bulk of water (of vice versa).

2006-10-08 02:08:23 · answer #5 · answered by Anonymous · 0 0

this is because the molecules in a liquid are always in "groups" moving randomly and the gravity also acts on them

2006-10-08 03:31:42 · answer #6 · answered by U know who 3 · 0 1

due 2 surface tension present in water droplet

2006-10-08 06:40:27 · answer #7 · answered by debikachakraborty 3 · 0 1

WHILE THE WATER DROP IS FALLING DOWN INORDER TO REDUCE THE PE IT ATTAINS THE SHAPE AS SPERICAL, ALSO TO REDUCE THE SURFACE TENSION.

2006-10-08 09:14:33 · answer #8 · answered by manu n 1 · 0 1

It is because of the gravitional pull of the earth

2006-10-08 02:45:43 · answer #9 · answered by hotchocredrose 3 · 0 1

bcose of surface tension ..... whtever dat means ...... get it?

2006-10-08 02:31:07 · answer #10 · answered by amazed !!! 4 · 0 1

fedest.com, questions and answers