In this chapter, we will understand about the scope and excitement of physics with the help of examples. First, we will understand the scope of physics.
The scope of physics means the extent or range of view. It is truly very vast and wide. The domain of physics covers an enormous range of magnitude of physical quantities, like length, time, mass, energy, etc. For example, the range of distance varies from 10-14 cm to 1025 m i.e. from the size of nucleus to the size of universe. The range of masses varies from 10-30 kg (mass of electron) to 1055 kg (mass of a universe). The range of time varies from 10-22 sec (time taken by electromagnetic radiation to cross a nuclear distance) to 1018 sec (life of sun). Thus, the scope of physics is vast.
Table of Contents
Therefore, the scope of physics is broadly divided into two groups, on the basis of magnitude of physical quantities involved in it:
- Classical physics
- Modern physics
Classical Physics
The knowledge of physics that had collected up to about the year 1890 is called classical physics. It mainly deals with the study of macroscopic object travelling with speed as compared to much less than the speed of light. In other words, classical physics mainly deals with macroscopic phenomena.
Macroscopic Domain:
The domain which includes the phenomena at laboratory, terrestrial, and astronomical scale is called macroscopic domain. It deals with things that are large in size. It includes both terrestrial and astronomical levels. For example, all the things we can see with our naked eyes, like humans, tress, birds, animals, vehicles, buildings, etc. come under the terrestrial level. All the celestial bodies like the planets, starts, and moon, come under the astronomical level.
Macroscopic domain also helps to study of the law of nature and natural phenomena, including particle interaction, thermal expansions, and gravitational force of attraction. There are the following subject or sub-disciplines included under this domain. They are as:
- Mechanics
- Electrodynamics
- Optics
- Thermodynamics
Mechanics:
This subject deals with the study of Newton’s laws of motion and gravitational law. It is basically related to the concepts of motion, position, and energy of particles or objects. For example, when we drop a very heavy object and a light object from the same height, both reach the ground simultaneously, appeared no less than a magic to a common person. The laws of Newton easily explained this magical observation.
Someone sitting in the train finds the persons on the platform moving in the opposite direction while a person on the platform finds the man in the train going away from him. The theory of relativity easily explained the contradiction of their observation. In mechanics, we get the knowledge of several exciting phenomena, such as the state of rest and motion of physical objects, propagation of water waves, sound waves in air, equilibrium of twisted rod, rocket propulsion by ejecting gases, etc.
Electrodynamics:
This sub-discipline deals with the study of electric and magnetic phenomena associated with magnetic and charged bodies. These phenomena are mainly based on the laws given by Coulomb, Oersted, Ampere, and Faraday. In electrodynamics, we acquire the knowledge of several exciting phenomena, such as:
- Motion of current carrying conductor in a magnetic field.
- A magnet pulling an iron piece towards itself.
- Bulb lights our house.
- Fan flows air
- Refrigerator prepares ice cream
- Air-conditioners give cool air in the room during summer seasons
- Propagation of radio waves in ionosphere and many more.
We study many of such exciting process in the electrodynamics.
Optics:
Optics deals with the study of light phenomena, such as reflection, refraction, diffraction, interference, polarization, dispersion, scattering, etc. For example:
- Why sky is blue?
- How do stars appear twinkling at night?
- Reflection and refraction of light
- Dispersion of light, etc.
Thermodynamics:
In thermodynamics, we study about the system in macroscopic equilibrium as well as changes in internal energy, temperature, entropy, etc. In thermodynamics, we get the knowledge of heat and energy and its conversion. For example, the study of heat helps us to know the rise and fall of temperature, working of heat engines, conductivity of heat, etc.
The laws of classical physics adequately explained the microscopic systems in which things are visible from the naked eye. But they were inadequate in explaining the behavior of microscopic systems. Classical physics also failed to explain the correct answer when applied to the fast moving particles. This led to the development of modern physics after the year of 1890.
Modern Physics
The knowledge of physics which had accumulated after 1890 and continued up to the present day is called modern physics. It mainly deals with microscopic phenomena.
Microscopic Domain:
The domain which includes all the phenomena at a minute scale like atomic, molecular and nuclear levels is called microscopic domain or microscopic phenomena. It mainly deals with the study of the interaction of particles at sub-atomic level like electron, proton, and other particles. For example, we know all things are made up of atoms in this universe. These atoms combine together to form molecules.
With our naked eyes, we cannot see them as atoms are very small in size. Each atom is composed of one nucleus, which helps us in understanding the microscopic domain of electron, protons, and neutrons. In modern physics, the quantum mechanics and the theory of relativity easily explained such microscopic phenomena.
E. Schrödinger, W. Heisenberg, and P.A.M. Dirac developed quantum mechanics in 1925. Quantum mechanics easily explained the behavior of sub-atomic particles and fundamental nature of matter. Einstein developed a special theory of relativity in 1905 for the particles that are moving with the speed equal to the speed of light. The theory of relativity easily explained the motion of objects moving with velocity comparable to light speed.
Under this domain, there are many discoveries classified into atomic physics, nuclear physics, quantum physics, bio-physics, medico-physics, etc.
Mesoscopic Domain:
The mesoscopic domain is the domain that lies in between the microscopic and macroscopic domains. It is also called mesoscopic physics. It deals with things which are neither small nor large in size and mainly used for research purposes. Rice, small insects, sand, etc. are some examples of the mesoscopic domain or physics.
Excitement of Physics
Physics is a very exciting subject that helps us to know the interesting facts or reasons for the day-to-day natural phenomena in our life. It helps to provide answers to exciting questions, such as:
- Why sky is blue?
- Why is sunset red?
- Why are atoms held together?
Beating of a drum causes vibration producing sound, and many more exciting questions.
In fact, there are numerous exciting such questions that physics provides answers.
There are many laws such as the law of nature, electromagnetic induction, Faraday’s law, etc. that are crucial for practical purposes. Modern devices and machines use these laws and principles of physics.
In addition to it, with the help of physics we also come to get the knowledge numerous natural topics like
- How does the television display the movies?
- How do the satellites work?
- How do the seasons or climate change?
- What are the different types of forces and how we apply them practically?
- Phenomenon of day and night on the earth.
These are only a few examples. In fact, there are a very large number of such facts and questions of which we can get answers using the concepts of physics.
In this chapter, we have discussed the scope and excitement of physics with the help of many examples. Although, the scope of physics is a very wide concept, mainly used in analytic properties, both qualitatively and quantitatively. There are a total of three levels of scopes in physics: microscopic, macroscopic, and mesoscopic levels.
These three levels of domains cover atomic, molecular, terrestrial, and astronomical. In addition to it, physics also helps in studying the physical laws with illustrations. It excites the people in numerous ways with its interesting facts and concepts. Hope that you will have understood the basic facts related to the scope and excitement of physics.
