Application of Physics and The Joy of Learning Physics

Application of Physics and The Joy of Learning Physics

It is well known that engineering fields like Mechanical engineering, Electronic and Communication engineering, Electrical engineering, Civil engineering, Automobile engineering, Aeronautical engineering, Aerospace engineering and Robotic engineering, requires ALL of Physics. You have to be excellent in Physics to do great in any one of these engineering fields. However there are plenty of other fields where you can apply your knowledge of basic Physics.

This article is about how having a basic knowledge of Physics will not go wasted even when you are not in any one of the above mentioned fields.

But before we start let me share a childhood incident of mine:

When I was a little child, I remember asking my father “How is Wasim Akram (an ex cricket player from Pakistan) able to swing a cricket ball to such a large extent?” He replied “If you don’t want to watch the match I’ll switch off the TV set”. I kept quiet and continued wandering about it.

I feel happy to say that if someday my students are asked the same question they will have an answer.

The answer is quite simple: Cricket players decide to keep shining one side of the ball (this is what they are doing when you see them rubbing the ball on the cloth). So, when the ball is moving you can imagine air rushing back towards the ball (Think of running fast, you will feel the air hitting you backwards). The air near the shiny side is moving past the ball much faster as compared to the air near the rougher side. (Think of sliding on a smooth floor and then on a rough floor, you will surely be able to slide faster in the smooth floor). This difference in speed of air in the two sides of the ball creates a pressure difference between the two sides and this pressure difference exerts a sideways force on the ball. This sideways force leads to the swing of the ball. This effect is called “Bernoulli’s effect”.

A very simple demonstration to show this effect is to blow air above a small piece of paper; you will find that the paper will be lifted up. The fast flowing air above the paper creates a low pressure area and the paper is lifted from higher pressure area (below the paper) to lower pressure area (above the paper). So you see having a basic knowledge of Physics helps us to understand things that happen around us. And this is what I call “The joy of learning Physics”!

[Note: To study the actual cause of the swing we also needed to apply turbulence of air near the rougher side of the ball but this is much more complicated which we do in higher physics.]

Let us now see how Physics is useful in different areas of study.

Architecture:

To be a good architecture, you need to know how different materials behave when forces are applied to them, what happens to them on heating, and how vibrations affect a certain material.

To decide the materials to be used for a particular structure (a bridge for example) you need to have an idea of the elastic strength of a given material. You don’t want your building to collapse due to an earthquake which is weak in strength!
Physics helps you to understand these concepts and make your life easy!

You will also be required to be good in Acoustics- the study of how sound behaves in a room. You don’t want to design theatres (e.g. a cinema hall) in which people in the last benches are unable to understand what the actors in the movie are saying.

Sports:

Even if it is not true that a good physicist must be a good sportsman, having the knowledge of some basic principles of Physics will help you to harness your abilities in whatever sports you play.

In cricket, by shining one side of the ball allows air to moves faster in that side. This results in a difference in air pressure between the two sides of the ball (We call this Bernoull’s principle). This in turn will cause a sideways force from higher pressure to lower pressure that allows the ball to swing as it moves.

A basic knowledge of how air moves around a spinning ball, will allow a footballer to curve the ball. It is called “banana kick”.
For similar reasons, the “dimples” in a golf ball allows it to go farther thus increasing its range (the distance between the point the ball starts to the point where it lands)

Medicine:

Whether you want to be a nurse or a surgeon understanding physics is important if you want to work in modern medicine.
Cancer is treated by using Gamma radiation (emitted by unstable nuclei like cobalt-60). You must know the units in which these radiations are measured. You don’t want to shine too less or too intense radiations in the area of the tissue which is damaged by cancerous cells.

To have a detail image of a bacteria or a virus, you must have the knowledge of microscopes or electron microscope works. The picture on the right shows the bird flu virus.

These days biophysicist ( People who use laws of Physics in living systems) are applying Quantum Physics ( A modern study of behavior of small things like electrons) to processes like photosynthesis, the sensation of smell, and even to the understanding of how our “consciousness” work.

The knowledge of the flow of fluids (liquids or gases) due to difference in concentration helps biologists to study the diffusion of materials through cell walls or membranes.

The knowledge of stability – how things stay at rest under the actions of forces help people to design prosthetics!
The knowledge of the laws governing the relation between current and voltage helps neurologists to understand how impulses travel through our brain nerves.

Humans produce sound by vibrating their vocal cord housed inside your larynx (voice box). If you ask how the cord vibrates, then the answer is based on an effect called Bernoulli’s effect (mentioned before) which is a taught in a basic Physics course. We produce different pitch (frequency) sounds by changing the thickness of the vocal cords. Why? Just like a thin guitar string produced higher pitch sound like “tiiiiii…nnng” and thick guitar strings produce low pitch sound like “dhhhaang”, changing the thickness of the vocal cord helps us to produce different pitch sound. The quality of your sound and how high can you sing depends on the size and shape of your vocal cord, the resonant cavities in your nose, mouth and throat.

Chemistry

A chemist must have knowledge of how electrons in an atom move. Chemical reactions are about rearrangement of electrons when two or more atoms come nearby in order to achieve more stability. Two atoms can form a covalent bond by sharing their electrons. The shared electrons are being attracted by the two atoms. This forms a tug-of-war between the two atoms and this mutual attraction is referred to a bond in chemistry.

Now, the motion of electrons in the early days was thought to be similar to that of planets. Electrons revolving around nucleus were considered as miniature planets revolving around the sun.

If you wander why electrons (which are negative) are not attracted towards the nucleus (which are positive), the answer is quite simple. If you drop a ball from rest then it falls towards the earth. But if you throw a ball horizontally, then it wants to continue its motion in the direction in which you threw it, however the gravitational force by earth makes it to follow a curved path. If you do this from a large height and with the right speed, then as the ball falls from its straight line path, it will miss the earth’s surface (which is also curved) and thereafter it continues to curve and revolve around the earth.

A very common question among the students is why moon is not falling towards the earth if earth attracts it. Well, think this way. If earth was not attracting moon then it would have continued to move in a straight line following the direction in which it initially started to move (the direction of motion which it had when it was formed).However, because of the earth’s gravitational attraction, it bends around the earth and follows a curved path around the earth. So, you see moon is actually falling away from the direction which it would have taken if there were no earth. In the same way, if the nucleus was not attracting the electron, it would have moved in a straight line, but due to the attraction of the nucleus the electrons falls from this straight line path and follows a curved path around the nucleus. One way of making the moon fall straight towards earth or an electron straight towards nucleus is to bring them at rest. Then just like a ball dropped at rest falls straight down, the moon will fall straight towards earth and electron straight towards the nucleus.

However, a problem was faced by atomic physicists. Planets around the sun can move in any orbit. In other words there is no rule or law that says planets cannot revolve in some orbits but can revolve in some specific orbits. Whereas, in the case of electrons it was found that only certain special orbits were allowed. In other words in some region of space around the nucleus the probability of finding the electron is zero or almost zero.

In Chemistry we define “orbitals” (see the pictures below) as the region in space around the nucleus where the probability of finding electron is maximum, and nodes are the region where the probability of finding the electron is zero.

This may sound strange to you. For example, if you ask me where my pen is, I will say it is on the table here or in my pocket here but I will never say the probability of finding the pen in my pocket is 80% but don’t be surprised if you found it outside my pocket! So, it is very clear that the motion or behavior of an electron is not same as the behavior of a pen. Physicist realized this, and created a new language for understanding the behavior of small particles like electron. This new language in which Nature speaks to us in the atomic world is called Quantum Mechanics.

In Quantum Mechanics, the very same electron can be in two or more places at the same time. What?! This may again not make sense, but that is the reality.

In Quantum Mechanics electrons are treated as waves. And wherever the amplitude of the associated wave is large, we say the probability of finding the electron is large.

Keep in mind that Quantum Mechanics was created not because Physicists wanted to make it more difficult but because Nature at its deep level is strange, perhaps stranger than you could imagine. You must also realize that physicists take a lot of pride in Quantum Mechanics as it has never failed and no experiment (as of now) violates the predictions of Quantum Mechanics. It is correct upto 6 decimal places!

Music and Television:

Knowledge of basic Physics will be useful to you even when you choose a career in entertainment business.
If you are a part of a group that would construct the next hi-fi action movie, believe me or not, you will be thankful to your Physics teacher for teaching you about how light and sound interacts with its surrounding matter.

There are people who use their knowledge of Physics to prepare for concerts. You want uniform distribution of sound in a concert hall.

While making TV programmes, knowledge of Physics will help you to do a much better job as you will know how cameras and lighting system works.

Being a musician you must know the characteristics of sound, and how these characteristics depend on the external conditions like the food items you eat before singing. You don’t want to have to clear your throat in the middle of your singing. You may also want to know why and how changing the tension in the string of your guitar or sitar changes the pitch of the sound it produces. You may teach music to some kids and if they ask a question to you, you better have a good answer.

Environment

Whether you want to be a storm chaser, investigate volcanoes for a living, develop new renewable energy technology, study how climate change is affecting the penguin populations or study the size of Sahara Desert- studying Physics is the path to huge range of exciting careers in environmental science.

The reason why we get seasons is because as the earth revolves around the sun, due to the tilt of the axis of Earth’s rotation, some parts of earth stays more in sunlight while other parts do not. Thus if parts in northern hemisphere are having longer days then parts in southern hemispheres will have longer nights.

The heat transfer in the atmosphere which brings about the climatic changes takes place via three basic modes: Conduction, Convection and Radiation. All these basic ideas are taught in any basic physics course.

Law

Forensic science is the application of science to criminal and civil laws.

Forensics requires knowledge of how things move under the action of forces. In the study of motion, a physics student can calculate the speed of a car (just before the driver applied brakes) by knowing the length of the skid marks on the rod in the case of a collision.

This is very useful in analyzing a crime scene or an accident.

What else…

At the end of this article, I would like to mention that even if you don’t take any of these careers; studying Physics will help you in many other ways. It increases your ability to reason, it teaches us to think in different ways when we find a problem, it helps us to develop determination for finding coherent answers and it teaches us to respect the views of others…. ..In fact in Einstein’s relativity all frames of reference are equivalent!

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