Scope and Excitement of Physics

The topics which we’ll cover in this lesson are, what is physics. The scope of physics, and excitement of physics. How physics led to the growth of technology, and society.

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Summary

• Physics comes under the discipline of Natural Sciences which also contains Chemistry and Biology.
• Physics attempts to explain the physical phenomenon in terms of laws.
• The two principal thrusts in Physics are Unification and Reduction.
• The scope of physics deals with macroscopic, microscopic and mesoscopic Phenomena
• Classical Physics deals with Macroscopic phenomena which include Electrodynamics, Thermodynamics, Mechanics, and Optics
• Quantum Theory deals with Microscopic Phenomena which includes  atoms, molecules, and subatomic particles

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Table of Contents

1. What is Physics
2. Physics and Nature
3. Scientific Method
   1. Theory of Gravity
   1. Scope of Physics
      1. Macroscopic Domain
      2. Microscopic Domain
      3. Mesoscopic Domain
   2. Excitement of Physics
4. External References

What is Physics or scope of Physics

So let us start with what is physics?. Physics is the general analysis of nature, conducted to understand how the universe behaves. In simple terms, we can say that physics is nothing but the study of nature and the natural phenomenon which we see around us.

Physics is the study of matter, energy and the interactions between them. The scope of physics is very broad as it deals with the most fundamental particles of matter to the entire universe. Some of the important concepts in physics include motion, magnetic and gravitational forces, and energy forms such as Sound, Light, and Electricity.

Natural Phenomenon and Physics

Let us think of any natural phenomena which we see in our day-to-day life.  For example, the twinkling of the stars which we see every night. Do you know what makes the stars twinkle?. There is a phenomenon called diffraction in physics, which is responsible for this phenomenon. Let us take another example where we see the apples fall down to the ground from the tree. Even though we are not applying any external force on the apple but it falls down to the ground.

Physics is there behind the beautiful rainbow, which we see after the rainfall. We’ll discuss all the phenomenon related to physics one by one in each of the lessons in this NEET Physics course.

Scientific Method

When someone talks about physics or science it is very important to know what is a scientific method? A scientist goes through a series of steps and then he finally concludes an invention. These series of steps together constitute the scientific method.  The first step is systematic observation, the second one is controlled experiments, and the third step is the qualitative and quantitative reasoning.  The fourth step is mathematical modeling and final step is verification or falsification of theories.  You must be finding the terms really difficult but we’ll discuss each of them in detail and simplify them.

How Newton Developed Theory of Gravity

We all know that the famous scientist, Newton discovered the famous universal law of gravitation but do you know how did Newton reach to the theory of gravity. We will see that now. Once it happened that Newton was sitting in his garden having a cup of tea. He observed an Apple falling down the tree. If you or I, see an apple falling down the tree, we would have just ignored and enjoyed our tea. Since it was Newton, he observed the phenomenon and deeply thought about it. He went ahead and performed several types of experiments regarding this phenomenon in his laboratory.

Newton actually performed the first two steps of the scientific method. The first one was systematic observation, wherein, Newton observed keenly that the Apple fell down from the tree. The second one was controlled experiments, where he went back and performed several experiments in his lab. The third Step he performed was qualitative and quantitative reasoning, Newton used different kinds of valid and invalid data to reach his conclusion.

During the reasoning step, he found that there was a force in nature which is responsible for making the Apple fall to the ground. In this step he used different kinds of data to prove or to conclude what is this force dependent on that is on what factors does this force depend on later.

What is Mathematical Modeling

After this, Netwon performed Mathematical Modeling. What is mathematical modeling? He reached to a mathematical derivation of the force. He defines the force of gravitation as something like G is equal to m1 m2 by r square.

[latex] F\;=\;G\;X\;\frac{m1\;\;X\;m2}{r^2}[/latex]

Don’t worry about such big formula, because we will study a chapter exclusively for this law of gravitation where we will discuss this law in detail. I am just trying to explain to you what are the steps through which Newton went to reach his famous theory of gravity.  Newton observed the Apple falling down the tree. He performed experiments in his lab. Next, he used a different kind of data to show what are the factors on which this force is dependent. He found it is dependent on mass and the distance between the bodies and finally concluded that this force is dependent on these factors. He finally verified that his theory is correct and it became the famous theory of gravity.

There is another term if you see here falsification. Sometimes what happens is, whenever a scientist gives a theory until and unless somebody else comes and proves it wrong it is accepted as a truth. If you see there is no theory in this world which is completely correct.  Newton’s theory of gravity was considered as a truth till many centuries. Several years later when something called quantum theory came into the picture. It was found that Newton’s theory or the theory of gravity failed at the quantum levels. So the quantum theory, kind of falsified Newton’s theory of gravity.

Quick Recap of Scientific Method

Let us quickly discuss the steps again in the scientific method, the first step is the systematic observation that is you have to observe something very keenly and very deeply. The second step is to conduct controlled experiments on that phenomenon. The third step is to do qualitative and quantitative reasoning by performing experiments you have to use all varieties of data to prove something correct or wrong. The fourth is mathematical modeling. In this step, you have to give a mathematical expression for whatever you conclude. The final step is the verification of the theory or the falsification of some earlier theory.

The scope of Physics

What is the scope of physics or how broad is physics to study? Broadly there are three domains of interest in physics they are the macroscopic domain, the Mesoscopic domain, and the microscopic domain. We’ll discuss each of these domains one by one.

Macroscopic Domain

Let us look at the macroscopic domain, so what do you think the macroscopic domain would be as the name suggests macro what does the word macro means.  Macro means big, something which is big in size. Scope means that the scope is big that is macroscopic. The macroscopic domain includes phenomenon and the terrestrial and astronomical scales. When I say terrestrial, I talk about things which we see around us.  For example, human beings, animals, trees, buildings and anything almost everything that is visible to us. They all fall under the terrestrial scale.  Similarly, when I talk of astronomical scales, I talk about all the celestial bodies, for example, the planets, stars, etc in the macroscopic domain. Macroscopic means dealing with things which are very big in size.

Microscopic Domain

Let us see the microscopic domain very similar to macroscopic that Micro means something which is very small in size so this microscopic domain includes molecular, atomic and nuclear phenomena. Do you think you can see a molecule with your naked eye?.  Of course not. All things we see around are made up of molecules which in turn is again made up of atoms and atoms and turn consists of the nucleus so just imagine how small things this microscopic domain deals with.

Mesoscopic Domain

Let us see the third one that is mesoscopic, the name suggests it is something in between macro and micro. It represents something in between these two so something in the middle of micro and macro that means something which is neither too big nor too small. The mesoscopic domain deals with a few hundreds or tens of atoms that mean it deals with several groups of atoms. These days, this mesoscopic domain is emerging as an exciting field of research you can see many people doing a lot of research on this domain now.

Macroscopic VS Mesoscopic VS Microscopic Domain

Let us have a quick comparison so that you can just relate it very quickly. Anything which we see around us is made up of matter correct this matter, in turn, is made up of molecules, in turn, is made up of atoms. These atoms, in turn, consists of nucleus so anything which we see around us they are all matter so this is the macroscopic domain. The molecules, atoms, nucleus they all fall under the microscopic domain and something in between these two means, mesoscopic.

Excitement of Physics

Let’s see what makes physics an exciting subject I mean why does a person want to study physics. For many, the first thing is carrying out interesting experiments in the laboratory. It is absolutely interesting you are going to learn something new every day and that too but whatever you yourself are doing so that’s absolutely interesting.

Discovering Secrets

The next is discovering secrets of nature as I told you the rainbow which is formed is big since childhood we are seeing a rainbow in the sky. But, we don’t know what makes a rainbow but later in life when you study and you come to know okay this is the reason which makes the rainbow formed it is very joyful.  To discover secrets of nature and to know about things which you already knew since childhood that also turns out to be very interesting. The third reason is applying laws of physics for practical purposes

Applying Laws of Physics

There are several concepts in physics like I’ll give you a small example like we study a phenomenon called electromagnetic induction. Using this principle, we generate the devices which we see around us like electric motors, electric generators, etc. They are all based on these principles of electromagnetic induction. There are several laws and physics which are finally used for practical purposes in some or the other way. All modern devices we use are possible only by the application of laws and principles of physics.

Physics Technology and Society

Next, we’ll discuss physics, technology, and society and how are they interrelated. At certain times what happens is technology comes first and then it gives rise to a new physics domain. When I say new physics I mean to say it gives rise to a new branch of study. We have several branches of study even inside physics sometimes it happens that a technology comes and then it leaves rise to a completely new branch of physics.

Technology to Physics: Heat Engine and Thermodynamics

The heat engine was discovered somewhere around 1700 approximately. After this heat engine was discovered, the scientists studied the principles which make the heat engine work.  Finally, they discovered a complete discipline of thermodynamics which is a very important and a very significant part of physics these days.  If you see that it was because of the heat engine that thermodynamics came into the picture.

Physics To Technology: Semiconductor Physics To Computer Technology

Sometimes, physics comes first and then it gives rise to new technology, for example, the silicon chip or the integrated circuit.  It was basically nothing but a combination of resistors, transistors, and other components. These resistors and transistors are nothing but they are a direct product of physics and from these chips and I see the entire computer revolution took place. The computer revolution which we see these days is nothing but technology.  But this technology came from core physics that is from the semiconductor physics so the theory of semiconductor physics gave rise to the computer revolution. We can say that physics and technology both of them can give rise to each other sometimes physics comes first and gives rise to technology at other times technology comes first and gives rise to physics.

External References

1. Introduction to Scientific Method by University of Rochester, NY
2. Scientific Method Video by Khan Academy

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