Pressure around us

 PRESSURE AROUND US 

Courage is grace under pressure. 

-Ernest Hemingway  

Here I am going to mention a pressure that is experienced by all living entities and even plays an important role in their life. It is " Air pressure". 

What is air?

Air is a mixture of many gases and tiny dust particles. Air can only exist inside a closed boundary like a bottle, cylinder, atmosphere, etc for life forms to exist. Surprisingly air is a perfect mixture of all the gases i.e air is homogeneous even though it is made out of different gases. So air can be considered a single entity.  

How do we interact with air? Without air we can't breathe, plants can't survive, we can't have a stable temperature, we can't fly, and many other interactions that we see, experience, and study it. 

What is pressure?

Pressure is the force that is produced when something is pressed by you or something is pressing you. Force is pushing or pulling, in this case, we can consider force as pushing. In science pressure is a physical quantity that is very useful in many concepts like hydrostatic pressure, thermal pressure, fluid pressure, differential pressure, gauge pressure, vacuum pressure, atmospheric pressure, water pressure, etc. 

Fluids

Water and gases are called fluids because they exhibit similar behavior that is they can take the shape of a container, are loosely packed, have thermodynamic properties, and can flow. With physical observation, we can say that fluid is a medium in a space that occupies the space and life exist in the fluid or with the help of fluids.

Water and life 

As humans, we can't see our faces with our senses but can see others' faces and learn from them in a similar way we don't realize our surroundings. Now let's learn from the life form in water. Take a fish in a pond, a pond has a closed boundary and the fish can move inside it. Now the fish needs oxygen and it gets the oxygen from the resolved oxygen in the water. As we see the fish moves freely in the water without any resistance because the fish lives in that environment. we can see fish living near the surface of the water and fish that go deep as 10000 feet quite interesting right!

Now the water at a depth provides some pressure because some amount of substance is above it. (when a pile of pillows is on your chest we feel pressure in a similar way there is a pile of water above that point). Now lets us do a little calculation to understand what is happing.

Consider a cuboid pond of the following dimensions  

10×10×200            (Length×Width×Depth )

Its volume is then given as a 20000-meter cube 

Now consider a fish at 10 meters depth. So it has 10 meters high water above it. 

So, The volume of water above it is a 10000-meter cube which is 10000000 kg of water or 980 KPa of pressure, Now with a sound mind, we can see the fish should be crushed with that weight but it does not, (We don't usually think this in this way but it is really interesting). A pressure of around 100 KPa is enough to crush a soda can. Here the fish does not get crushed because it doesn't have air inside it and it is mostly fluid so it will balance its body pressure with the water pressure and move around.  

Humans, fish, and air

As land-living creatures, we move around the land in a medium filled with air which we don't notice because it is a part of us. 

We don’t even realize we are experiencing air pressure until we actually look for it. The things we don’t see at first, and take for granted, like gravity and air pressure, turn out to be among the most fascinating of all phenomena. It’s like the joke about two fish swimming along happily in a river. One fish turns to the other, a skeptical look on its face, and says, “What’s all this new talk about ‘water’?” from the lectures of Walter Lewin. 

We live at the bottom of the ocean 

From the above discussion, we should come to the idea that we live at the bottom of the ocean which is made up of air, which exerts a huge amount of pressure on us every second of every day. Suppose you hold your hand out in front of you, palm up. Now imagine a very long piece of square tubing that is 1 centimeter wide balanced on my hand and rising all the way to the top of the atmosphere. That’s more than 7000km (More precisely 10000km). The weight of the air alone in the tube (forget about the tubing just think of air or the jube is made up of air). That’s one way to measure air pressure: 1.03 kilograms per square centimeter of pressure which are called the standard atmosphere or 100Kpa. Which is huge. (From Walter Lewin Lectures and demonstrations)

Another way to calculate air pressure is with a fairly simple equation. Pressure is force divided by area: P = F⁄A. So, air pressure at sea level is about 1 kilogram per square centimeter. We know the relation between force, pressure, and area. The larger the area, the lower the pressure, and, conversely, the smaller the area, the larger the pressure. 

Now stretch out your hand (palm up) and think about the force exerted on your hand. The area of your hand is about 10 square centimeters, so there must be a 70-kilogram force, about 70 Kg, pushing down on it. Then why you are able to hold it up so easily?  Because the pressure exerted by air surrounds us on all sides, and there is also a force of 70 Kg upward on the back of your hand. Thus the net force on your hand is zero. Then why doesn’t your hand get crushed if so much force is pressing in on it? Clearly, the bones in your hand are more than strong enough not to get crushed. (From Walter Lewin Lectures and demonstrations)

How about my chest? It has an area of about 1,000 square centimeters. Thus the net force exerted on it due to air pressure is about 1,000 kilograms: 1 metric ton. The net force on my back would also be about 1 ton. Why don’t my lungs collapse? The reason is that inside my lungs the air pressure is also 1 atmosphere; thus, there is no pressure difference between the air inside my lungs and the outside air pushing down on my chest. That’s why I can breathe easily. Take a cardboard or wooden or metal box of similar dimensions as your chest. Close the box. The air inside the box is the air you breathe—1 atmosphere. The box does not get crushed for the same reason that your lungs will not collapse. Houses do not collapse under atmospheric pressure because the air pressure inside is the same as outside; we call this pressure equilibrium. (From Walter Lewin Lectures and demonstrations)

So it is really fascinating to think about the things around us. 

Hope this article was useful and I hope you learned something from it.

If you have any theories or questions regarding this you are free to express them in comments or you can chat with me on my Instagram page https://www.instagram.com/phy.sci/?hl=en.

See my previous posts 

Science of pencil

Empiricism and Rationalism

Water and life

Why do remotes work when we smack them?

Vibration - Eternal motion

For previous articles on this follow the following link

TAU1: https://jjohnpaul.blogspot.com/2021/04/mysteries-of-fountain-pen.html

TAU2 : https://jjohnpaul.blogspot.com/2021/06/tau2-egg-is-violating-physics.html

TAU3: https://jjohnpaul.blogspot.com/2021/07/tau-3-color-of-clouds.html

TAU4: https://jjohnpaul.blogspot.com/2021/07/tau-4-peace-be-with-elements.html

TAU 5: 

https://jjohnpaul.blogspot.com/2022/02/tau-5-why-do-remotes-work-when-we-smack.html

IF ANY DOUBTS AND CLARIFICATION YOU CAN COMMENT HERE.

IF ANY INFORMATION IS INACCURATE I AM READY TO CORRECT IT

  

 

What makes us do things- Force

What makes us do things - Force

Man masters nature not by force but by understanding.

- Jacob Bronowski

https://briankoberlein.com/blog/four-horsemen/

 It would be better if we were children because we would ask lots of questions to our elders which may seem silly but are essential to understand nature in is the way. Why do things move? Why do things stand? Why something stops when we catch it?..... and more. 

All motion and nonmotion, (simply to say everything) begin with a force that does some work on them. When we put forces in words we have "PUSH and PULL". People generally have an awareness of many kinds of force like contact force, non-contact force, gravitational force, electric force, nuclear force, and more.

PUSH AND PULL

Push and pull are the activities that we do in our everyday life. These two simple yet important actions make the entire universe stand as it is. When you want to carry anything you pull it. When you want something to go out of the way you puss it. These actions are our fundamental motions. This blog has been typed and while typing I push each key on the keyboard to make them appear on the screen, we use mobile while using it we puss the mobile screen so we can scroll or click on some app and we pull the mobile by lifting it this way everything that we do is push and pull so we are essentially living by exerting to taking the force.

FORCES ALWAYS COMES IN PAIRS

I would have explained push and pull separately but I did not do this because of some interesting and important reasons. Take your thumb finger and press against the wall as hard as you can after a certain time you will feel some pain in your finger which indicates that something has pressed your thumb but it was you pressing the wall. So the only possible explanation that we can give is that the wall has pressed against your finger. In simple words, you exert some force to the wall in return the wall returns the same amount of force in your hand.  So the wall is giving a reaction to your action. This is what newton's third law of motion says "Every action has an equal and opposite reaction".

So forces always come in pairs. This gives us a lot of information. Now, let's take the simple action of walking. When you walk you push (a backward action force) your foot against the ground in return the ground push (an opposite reactive force) your foot in the same amount so that you can lift and start the move, by this way you are able to walk.

IMPORTANT ASPECT OF FORCE

Now if one eat some food say garlic bread one should be concerned only about the quantity of the food that he is taking in in order to avoid indigestion but while one is driving the car only the quantity called speed is not enough because the speed will give you the time to reach a place, your mileage, the engine tolerance but you need velocity which is same as speed but in a particular direction because one can't just reach a place just by driving in 60 km/hr it requires direction to be more specific so such quantities which require the additional information of direction other than the quantity are call as vectors.

So, let us come to force. Definitely, force is expressed in a number rather than a collection of greek symbols for example weight of something is actually a number that we can comprehend. Then why it is a vector? Now take the weight, weight is fundamentally a force acting on mass i.e. the force of acceleration due to gravity acting on a mass. So, the weight is always in the direction of ground (more scientifically it is pointed to the core of the earth) this is the reason for us to pull i.e pull the mass in the opposite direction of its original direction in order to lift it. I hope this makes sense. 

UNDERSTANDING FOUR BASIC FORCES IN NATURE

http://countinfinity.blogspot.com/2010/08/four-fundamental-forces.html

GRAVITATIONAL FORCE

Gravitational force is the weakest fundamental force of all forces the reason will be explained later in the upcoming topic. Think of a demon sitting inside at the center of the earth and he has attached every object including a small grain of sand to Mt. Everest with an invisible string continuously pulling them towards it. As there is the number of objects the force is little but still, it is pulling us all and keeping us in place. In a similar way, there is a demon in every object in the universe which attaches an invisible string to the other objects and pulls them. 

As the gravitational force always pull it is an attractive force. This gravitational force on earth s called gravity. As for every physical phenomenon, there is a mathematical form there is a simple mathematical expression for gravitational force among two objects. It is given as follows

Gravitational force =  Constant (Mass of one object) x (Mass of another object)  / 2 x (distance b/w them)                                                                              

So this means that if the mass is high the force is high and if the distance is small the force is high. So any two bodies in the world can exert a gravitational force. For instance, my laptop and I self which is 1 meter apart has a gravitational force of  0.00000001048 Newton which is not significant but the gravitational force between earth and the sun is 37500000000000000000000000 Newton which is very significant ad strong.

The gravitational force is the reason we stay in the place we want and the planets revolve in a peaceful manner.

https://socratease.co/content/gravity-1/intro

WEAK INTERACTIONS

Unless and until one is unfamiliar with nucleus and atoms in a deep sense it is difficult to grasp this nature of force but I will give the information about it to know about it in a basic sense.

The weak nuclear force (or just the weak force, or weak interaction) acts inside of individual nucleons, which means that it is an even shorter range than the strong nuclear force. It is the force that allows protons to turn into neutrons and vice versa through beta decay. This keeps the right balance of protons and neutrons in a nucleus. The weak force is very important in the nuclear fusion that happens in the sun. It is quite hard to understand at the beginning.

ELECTROMAGNETIC FORCE

Electric force and magnetic force are entirely different forces but are similar in many ways. The electric force acts between all charged particles, whether or not they're moving. The magnetic force acts between moving charged particles. This means that every charged particle gives off an electric field, whether or not it's moving. Moving charged particles (like those in electric current) give off magnetic fields.

Even though it looks live very small it is very essential in the structural integrity of all the objects in the universe. Solids stay solid due to this force. this force is far stronger than the gravitational force. The goosebumps that soccer, when you are excited, is also due to electrostatic force.

STRONG INTERACTION

The strong force is 'felt' between nucleons (protons and neutrons) inside of the nucleus of an atom. The strong nuclear force is sometimes referred to as just the strong force or the strong interaction. This force is strong enough that it overcomes the repulsive force between the two positively charged protons, allowing protons and neutrons to stick together in an unimaginably small space. The strong force dies off with distance much faster than gravity or the electromagnetic force, so fast that it's almost impossible to detect the strong force outside of a nucleus. A full treatment of the strong force requires many years of intensive study.

These four fundamental forces make the basic operation of puss and pull to keep the thing as they are. A greater understanding of these forces is given in general relativity (basically fancy complex topics). 

OTHER TYPES OF FORCE

CONTACT FORCE: The contact force is essentially the forces that are caused by the contact of two or more bodies like pushing a door, friction while rubbing something, pressing the keys on the keyboard, lifting objects, and more.

NON-CONTACT FORCE: The non-contact force are the force that acts without contacts like the attraction of compass needle to the north, the attraction of earth and sun and moon and earth, and many more. all the fundamental forces are the non-contact forces.

HOW FORCE IS REPRESENTED IN PAPER?

It is important to represent something that we see in the real world which is very essential for formulating the knowledge from the observations. So as all vectors, force is represented using an arrow (↗). The arrow essentially points in the direction of force and the length of the arrow in general roughly represents the magnitude of the force.

Description of force on fall in objects. Different masses experience different magnitudes of force.

(stimulation made by J John paul)

CONSEQUENCES OF FORCE IN REAL-TIME EXPERIENCE

We experience force all the time but we never take it into the account. The wired feeling when you are in a moving lift, the pain in your foot after a long walk, deformation of the tire after long use, and many more things. 

When you stand straight almost all the forces acting on us like the gravitational force, the normal force, the frictional force, and other forces will be in perfect balance and give us less pain but when you keep your hands parallel to the surface your shoulder bared some weight and causes pain after some time this is because the forces are not in balance and thus causes problems.

The beauty of projectile motion, the amazing water fountains, spider webs, and many other natural structures are a unique combination of forces. All your electrical devices work due to the electromagnetic force. The vision of the human eye is due to the fact that electromagnetic waves exert force in your eyes. There are many more things about forces that can be stated.

The mathematical aspects of force will be covered in a separate article.

  

TAKE SOME TIME EVERYDAY AND START EXPERIENCING THE THINGS AROUND YOU TO UNDERSTAND YOURSELF AND THE WORLD

HOPE THIS WAS USEFUL

TO SEE MY OLDER POSTS CLICK THE FOLLOWING LINK BELOW

https://jjohnpaul.blogspot.com/2021/03/

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Hope this article was useful and I hope you learned something from it.

If you have any theories or questions regarding this you are free to express them in comments or you can chat with me in my Instagram page https://www.instagram.com/phy.sci/?hl=en.