What is Physics? Definition, History, Importance, Scope

The most curious mind out of all the species is the mind of homosapiens. Humans are always curious about the nature around them and the magic laws on which it functions. The sun always rises in the east and sets in the west, the moon appears at night and the sun appears in the day, and so on. All these questions not on make humans curious but make them think and discover about the different theories of nature and by doing so, humans soon started discovering physics in order to discover the world and its mystery. Let’s learn what is physics in more detail,

What is Physics?

The word “science” has been originated from a word in the Latin dictionary named “Scientia” which means “to know”. Therefore, in one way, it can be said that science is nothing but to know the working of everything, from nature to machines. Under science, a category well known is nature science, which is the study of the physical world around humans. Physics, chemistry, biology, geology, all these fields lie under nature science.

A basic discipline of nature sciences is physics. Physics is also a word taken from the Latin dictionary which means nature. In Sanskrit, it is known as “Bhautiki” which is the physical world around. The definition of physics is not accurately present but it can be said that physics is the study of all basic laws of nature and their manifestation in a different phenomenon.

Physics as a whole explains the diverse physical phenomenon with respect to concepts and laws. For instance, from the falling off an apple on the ground and the law associated with it to the revolving of planets around the sun, to electromagnetism and its effects, physics defines it all. The major concept involved in physics is the use of basic approaches for bigger and complex problems, the process of solving a complex problem by breaking them into smaller parts is called reductionism. Then the act of unifying different laws is called unification.

History of Physics

The word science has been originated from a Latin word named “Scientia” which means “to know”. The word “Physics” has been originated from a Greek word named “Phusike” which means nature. In Sanskrit, physics is called “Vigyaan” which means “knowledge”, all of these words simply tell that physics is as old as the human species. Early civilizations like Egypt, India, Greece, etc, made a significant contribution in the field of physics. From the 16th century, Europe participated heavily and contributed. By the mid-twentieth century, science became an international enterprise and the rapid growth in the very field is on. The two major approaches in physics are already described above, they are unification and reductionism. 

Importance and application of physics

• The complex and bigger magnitude identities are explained using simpler theories.
• New devices are invented using the basic physics laws.
• The observations and experiments can be used to create new laws or to modify the existing laws.
• The ultimate aim is to find a unified set of laws that govern matter, energy, motion at both microscopic and macroscopic levels.

Scope and Excitement of Physics

The scope of physics can be majorly understood by looking at its sub-divisions. There are basically two types of studies in physics, macroscopic physics, and microscopic physics. Macroscopic physics deals with phenomena on a terrestrial, astronomical scale, while microscopic physics deals with the phenomenon on an atomic, molecular, or nuclear scale. The macroscopic study is done mostly in classical physics that includes subjects like mechanics, thermodynamics, etc. The microscopic study is the study of the structure of the atom, etc. Classical physics is unable to contribute in this field and currently, quantum theory is referred for the microscopic level studies.

Therefore, it can be said that the scope of physics is really very vast. The study covers a plethora of physical quantities like length, mass, time, energy, etc. From the study of smallest quantities (ranging up to 10^-30 or less) to the study of the quantities on an astronomical level (ranging up to 10²⁰ or more).

Fundamental forces in Nature

Force is seen and experienced on a daily basis and is available on both macroscopic and microscopic levels. At a macroscopic level, apart from gravitational force, several kinds of forces are experienced, for instance, muscular force, contact forces, the elongation or compression of elastics, etc. On a microscopic level, there are electric and magnetic forces, nuclear forces, etc. Although, it was further observed that most of the forces defined or explained are derived from four fundamental forces. The four fundamental forces in nature are,

• Gravitational Force: It is the mutual force that occurs between two objects by the virtue of their masses. Gravitational force is a universal force. The formula for gravitational force is,

F_G = (G M₁M₂)/r²

F_G = Gravitational force

M₁, M₂ = Masses1 and 2.

r = distance between the center of the masses.

• Electromagnetic force: It is the force that occurs between the charged particles. If the charges are at rest, the phenomenon of electric field occurs and if the charges are moving, both electric and magnetic field phenomenon occurs. Therefore, it is named electromagnetic force.
• Strong nuclear force: It is the strongest force among all four fundamental forces. This force binds the protons and neutrons in a nucleus. This force is charge independent, that is, it acts on proton-proton, proton-neutron, etc.
• Weak nuclear force: Weak nuclear force is not the weakest force among fundamental forces. It is not as weak as a gravitational force but is weaker than the electromagnetic force. This force is observed in only some nuclear processes, for example, β-decay of the nucleus.

Conceptual Questions

Question 1: Which of the four fundamental forces is the weakest and the strongest?

Answer: 

The weakest force in nature is the gravitational force and the strongest force in nature is the strong nuclear force.

Question 2: What are the laws of conservation in nature?

Answer:

Following are the laws of conservation in nature:

1. Law of conservation of mass.
2. Law of conservation of energy.
3. Law of conservation of momentum.
4. Law of conservation of charge.

Question 3: On what two things the scope of physics is defined?

Answer:

The two things on which the scope of physics is defined are unification and reductionism. Unification is the physics of unifying all laws. Whereas, reductionism is the process of solving complex problems by breaking them into simpler parts.

Question 4: What part of the study is not handled by the classical study of physics?

Answer:

The microscopic study of the physical world is not handled by classical physics. A new field termed quantum theory handles the study of physics at the microscopic level.

Question 5: Give an example of a weak nuclear force.

Answer:

The weak nuclear force is observed in a few nuclear processes. An example of a weak nuclear force is the β-decay of the nucleus.