So let's start with...
WHAT is Pressure ??
The physical force exerted on an object is known as Pressure.
It is also defined as the force applied perpendicular to an object's surface per unit area over which that force is (applied/distributed).
Further, it can also be described as the force-to-area ratio (over which the force is acting).
WHAT units are used to measure pressure ??
S.I Unit: N/m2 ( Pascal )
CGS Unit: barye ( Ba )
WHICH instruments/measuring device is used to measure Pressure ??
Barometer
Piezometer
Manometer
Bourdon Tube Gauge
Diaphragm Pressure Gauge
Depending on where and how much pressure is to be measured the instrument is selected by the operator.
Does Pressure vary with other aspects such as Temperature, Altitude ??
YES
As the temperature increase, the Pressure also Increase. Considering, the pressure exerted by the gas on the container's walls when the temperature rises, the particles move quicker, resulting in higher speeds, increased momentum, and therefore more force as they collide with the walls, causing the pressure to increase.
Pressure decreases with increasing altitude. The density of air decrease with an increase in Altitude which indicates that there will be fewer particles in the air that can exert a force which in turn leads to a decrease in Pressure.
Pressure increase with a decrease in the surface area of the body that will be exerting force. Considering a knife that has a very sharp edge i.e its surface area of contact is less will exert greater pressure on the object being cut which will result in the lesser effort being applied by the individual to cut. Whereas in the same situation if the knife would have been blunt then the area of contact of the knife would be more which would lead to less pressure applied on the object to be cut and the individual will have to apply more effort/force to cut the object.
WHAT is/is the significance/application of Pressure in our daily life ??
By using a knife to cut any material, if the knife has sharp edges, the user would not have to exert much effort to cut the object because its contact area is reduced, resulting in more pressure being exerted and the object being cut down with ease. If the edges were blunt, the person will have to exert more effort to cut down the same object because then the contact area is increased, resulting in less pressure being generated on the object and making this somewhat harder to cut.
The bags' straps and handles are made broader to ensure that the load is spread equally. The reasoning behind this is that as the surface contact area of the bag strap increases, the weight acting on the individual's hand or shoulders reduces as it gets distributed, allowing him or her to hold the bag even though it is heavy with comfort.
Trucks carrying heavy load have more than 4 wheels so that the load gets distributed evenly and tyres don't burst out. Basically whenever you came across trucks you might have seen that the front most axle of it has 1tyre each on the either sides whereas, the rear axles that placed below the container have 2 wheels each on the either sides i.e 4 wheels on the same axle. This enables it to carry heavy load with any tyre load issue
Syringes that are being used also operate on the principle of Pressure. As the Plunger is pulled out gently from the barrel the pressure inside it Decrease that and when such syringe is immersed into the medicinal bottle the medication (liquid) inside it enter into the barrel of the syringe through a small hole in the needle of the syringe. This takes place as the fluid flow from higher pressure to lower pressure region.
Also, the vacumm cleaner works on the same principle as that of the syringe. The only change here is the medium being sucked or collected. A vacuum cleaner has a fan inside that creates a low pressure inside the device. Consequently, air and dirt particles are sucked into the device.
The pressure inside the lungs increases and decreases with each breath. The pressure drops to below atmospheric pressure (negative gauge pressure) when you inhale, causing air to flow into the lungs. It increases above atmospheric pressure (positive gauge pressure) when you exhale, forcing air out.
So we can conclude that Pressure plays a very important role in our daily life right from breathing to eating and then cleaning. The day Pressure ceases it would be the end for almost everything on Earth, for humans, it would be difficult to breathe because a decrease in air pressure means that the density of air is reduced which in turn indicates that the quantity of Oxygen of air is also limited and humans would eventually die. Even the most precious stone in the world "DIAMOND" is formed under extreme heat and pressure. Thomas Carlyle a Scottish historian, philosopher, mathematician, and teacher also quoted "NO PRESSURE, NO DIAMOND." Further William Saroyan, an American writer said "Without Pressure, the Work doesn't get done at all." even though this might sound philosophical it has a great scientific baseline.