Hi friends in this article we try to learn the topic What Surface Tension is? it's Example, SI Unit and Applications it is important pint in fluid mechanics so without wasting of time let's discuss the further information in detail,
Contents Covered :
a) What Surface tension is?
b) What surface tension is formula
c) SI Unit of Surface tension
d) Causes of surface tension
e) Applications of Surface Tension
f) Example of surface tension
a) What Surface tension is?
Surface tension is a phenomenon that arises from the cohesive forces between molecules at the surface of a liquid. In other words, it is the tendency of liquid molecules to stick to one another, creating a surface layer that behaves like a thin, flexible membrane.
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The molecules at the surface of a liquid experience an imbalance of forces, with cohesive forces pulling them inward towards the bulk of the liquid, and adhesive forces with the surrounding air or other surfaces pulling them outward. The resulting tension between these forces is what creates the surface tension.
Surface tension is responsible for many interesting and useful phenomena, such as the ability of insects to walk on water, the formation of droplets, and the behavior of soap bubbles. It is also an important factor in many industrial processes, such as the manufacture of textiles and the production of coatings and adhesives.
b) What surface tension is formula
Mathematically, it can be the following formula:
γ = F / L
Where:
γ = Surface tension is N/m or J/m²
F is the force
acting perpendicular to the surface of the liquid in N or J
L is the length
of the line on the surface of the liquid in m
The unit of surface tension in the SI system is Newtons per meter (N/m) or Joules per square meter (J/m²).
This formula
shows that surface tension is directly proportional to the force acting
perpendicular to the surface, and inversely proportional to the length of the
line on the surface. In other words, the smaller the length of the line, the
greater the surface tension of the liquid.
c) SI Unit of Surface tension
The unit of
surface tension in the International System of Units (SI) is Newtons per meter
(N/m) or Joules per square meter (J/m²). Both units represent the amount of
force required to break or distort a surface film per unit length or area.
However, other units such as dynes per centimeter (dyn/cm) or ergs per square centimeter (erg/cm²) are also used in some fields of science and engineering, although they are not part of the SI system.
In summary, the
SI unit for surface tension is N/m or J/m².
d) Causes of surface tension
Surface tension is caused by the attractive forces between molecules at the surface of a liquid. Specifically, it is due to the difference in intermolecular forces experienced by molecules at the surface of a liquid compared to those in the bulk of the liquid.
The attractive forces between molecules are known as cohesive forces. At the surface of a liquid, the cohesive forces between molecules are not balanced by an equal attraction from other molecules above them, as they are in the bulk of the liquid. This leads to an imbalance of forces, resulting in a net inward force that pulls the surface molecules together, creating surface tension.
Surface tension can also be affected by temperature, pressure, and the presence of other substances in the liquid. For example, the addition of a surfactant or soap to water can lower the surface tension by disrupting the cohesive forces between water molecules, making it easier for the liquid to spread out and form a thin film.
In summary,
surface tension is caused by the attractive forces between molecules at the
surface of a liquid, and can be influenced by various factors including
temperature, pressure, and the presence of other substances.
e) Applications of Surface Tension
Surface tension has a wide range of applications in many fields of science, engineering, and everyday life. Here are a few examples:
Adhesion and Cohesion: Surface tension plays a crucial role in the adhesion and cohesion of materials. For example, in the production of adhesives, surface tension is used to determine the bonding strength of the adhesive.
Surface Coatings: Surface tension is also used in the formulation of surface coatings, such as paints and varnishes. The surface tension of the coating material determines how well it will adhere to the surface being coated, and how evenly it will spread out.
Droplet Formation: The surface tension of liquids is responsible for the formation of droplets. This property is useful in many applications, such as inkjet printing, medical microfluidics, and the manufacturing of aerosols.
Water Purification: Surface tension is used in the process of water purification, where a membrane with small pores is used to filter out impurities. The surface tension of the water helps to push it through the pores of the membrane.
Food Science: Surface tension is also important in the food industry, where it is used to control the texture and consistency of foods. For example, the surface tension of chocolate is what gives it its glossy appearance and snap when it is broken.
Biological Systems: Surface tension plays a critical role in the functioning of many biological systems, such as the alveoli in the lungs, which help to exchange gases between the air and the blood. Surface tension also helps to keep the surface of the eye moist and protects it from drying out.
These are just a few examples of the many applications of surface tension in different fields.
f) Example of surface tension
A common example of surface tension is the behavior of water droplets on a smooth surface, such as a freshly waxed car or a leaf. Water droplets tend to form spherical shapes due to the surface tension of water molecules, which pulls the liquid into the smallest possible surface area.
Another example
of surface tension is the ability of some insects, such as water striders, to
walk on the surface of water. This is possible because the surface tension of
water allows the insect's weight to be supported by the surface of the water,
without breaking through and sinking.
Soap bubbles are another example of surface tension. When soap is added to water, it reduces the surface tension, allowing the water to spread out more easily and form a thin film. When air is blown into this film, it creates a bubble, which is held together by the surface tension of the soapy water molecules.
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