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Pressure
The concept of pressure was brought into light by Italian physicist and mathematician Evangelista Torricelli. He also invented the barometer in 1643. A device to measure the atmospheric pressure of the earth.
Before going into depth let us understand pressure using some examples. . Consider a balloon filled with air. When the balloon is filled with air its air particles want to come outside of the balloon exerting pressure on the walls of the balloon. Here, the force exerted by the air on the walls of the balloon is called pressure. Particularly, understanding about definition. The amount of force exerted by air particles on 1 cm2 or 1inch2 or any unit area is called that particular pressure.
If we understand it with another example, consider an empty bottle and crush it. Now, open the cap and blow some air inside the bottle. You’ll see the bottle tries to become uncrushed (back to its original shape). This is happening because when we blow the air inside, the number of molecules of air inside the bottle increases which leads to an increase in density inside the bottle. And relatively outside the bottle air density is low. Due to this, the air particles try to go outside of the water bottle and push the surface of the water bottle till it comes to its original shape. Here, the force exerted by the air particles on the surface of bottle walls to push them to their original shape is called pressure.
Now, what is pressure and its definition?
Pressure is the force that is applied perpendicular to the surface area of any object per unit area of that surface.
The formula of Pressure:
Where,
P = Pressure Force
F = Perpendicular force applies
A = Area
There are many units by which pressure can be denoted. The SI unit of force is Pascals (Pa). But according to its formula, many units can be derived such as Newton per square metre (N/m2), pound-force per square inch (psi), etc. It is also denoted using standard atmospheric pressure (atm).
Here the force is a vector quantity. A vector quantity is a quantity that has both a magnitude and a direction. The force has some magnitude and it also has a direction of application.
Types
The concept of pressure is applied to various places such as fluid, air, vapour, and other gases. There are many types of pressure. Let us discuss some of them.
Fluid Pressure
This is pressure-related with fluid or fluid flow. Such as the pressure in the fluid flowing through a pipe comes under moving fluid or pressure inside any container containing fluid comes under static fluid and is known as hydrostatic pressure. The concept of this fluid pressure has come to light by two mathematicians Daniel Bernoulii and Blaise Pascal. And thus it is governed by Bernoulli’s equation given by Bernoulli.
Vapour Pressure
Vapour pressure can be considered in a closed system being in a thermodynamic equilibrium state. The pressure exerted by a vapour in that condition is known as vapour pressure. One of the best examples of vapour pressure can be a tea kettle.
Liquid Pressure
It is the pressure felt by any object kept underwater, such as a submarine. When a submarine is inside the sea, the deeper it goes, the more will be the liquid pressure. Liquid pressure is the weight of liquid above that particular object.
Liquid pressure is also directly proportional to density of the liquid. The more the density is, the more will be the liquid pressure.
It is governed by equation:
Ideal Gas Pressure
An ideal gas is a gas whose molecules occupy no space and doesn’t even interact with each other. In reality, this kind of gas never exists. But to simplify the complex gaseous equation the concept of an ideal gas was brought.
So, according to an ideal gas, its pressure is directly proportional to the temperature and quantity of the gas and is inversely proportional to the volume of the gas.
With the help of the equation it can be understood by:
Uses
The concept of pressure is widely used almost everywhere, from our daily life to industrial purposes. For example, the edge of a knife. It has very less area on the edge thus very less pressure is required to cut any vegetables. Another example is a syringe which when is pulled from the backside the pressure inside it decreases. And to bring the system into equilibrium blood is sucked into the syringe.
Large-scale industrial examples are compressors in jet engines. Very high pressure is generated from jet engines compressors which are then burned and used to propel the aircraft. Another example is the usage of submarines. Where submarines are put into the deep sea where there is immense pressure acting on them. So, the designer needs to calculate every pressure that will act on the submarine which the submarine can withstand.
Summary
To sum up, pressure is a very important concept which is used everywhere. It is a force acting in a perpendicular direction to anybody or object. According to the formula, if the area of the object on which force is acting is low, pressure will be comparatively high on that area. And vice versa happens if the area on which force is acting is large.
