Physics: Definition and Branches
What is Physics
The word physics has been derived from the Latin word physica, which means natural thing. Though, there are many definitions of physics, yet it can be defined as “The study of the properties of matter, energy and their mutual relationship is called physics.” According to Microsoft Encarta, “Physics, major science, dealing with the fundamental constituents of the universe, the forces they exert on one another, and the results produced by these forces. Sometimes in modern physics a more sophisticated approach is taken that incorporates elements of the three areas listed above; it relates to the laws of symmetry and conservation, such as those pertaining to energy, momentum, charge, and parity.” It means that physics is the branch of science, which deals with the properties of matter and emery and the relationship between them. It also tries to explain the material world and the natural phenomena of the universe. The scope of physics is very wide and vast. It deals with not only the tinniest particles of atoms, but it also dwells upon natural phenomenon like galaxy, milky way, solar and lunar eclipse etc.
Branches of Physics
A branch of physics, which is mainly concerned with the laws of motion and gravitation of Sir Isaac Newton and James Clark Maxwell’s Kinetic theory and thermodynamics, is called classical physics. Classical physics is mainly concerned with matter and energy. In classical physics energy and matter are considered as separate entities. Acoustics, Optics, Classical mechanics and electromagnetics are the traditional branches of classical physics. Moreover, any theory of physics, which is considered null and void in the modern physics, automatically falls under the realm of classical physics.
Modern physics is the branch of physics, which is mainly concerned with the theory of relativity and quantum mechanics. Albert Einstein and Max Plank were the pioneers of modern of physics. They were the first scientists who laid down the foundations of modern physics by introducing the theory of relativity and quantum mechanics respectively. In modern physics energy and matter are not considered as separate entities; rather they are considered as different forms of each other.
Nuclear physics is the branch of physics which deals with constituents, structure, behaviour and interactions of atomic nuclei. Encarta dictionary defines the nuclear physics as “the branch of physics in which the structure, forces, and behavior of the atomic nucleus are studied.” In the modern age, nuclear physics has got a very wide scope. It is used in power generation, nuclear weapons, medicines etc.
Atomic physics is the branch of physics which deals with the composition of atom apart from nucleus. It is mainly concerned with the arrangement and behaviour of electrons in the shells around the nucleus.
Geophysics is the branch of physics which deals with the study of earth. It is mainly concerned with the shape, structure and composition of earth. It also studies the gravitational force, magnetic fields, earthquakes, magmas, eruption of volcanoes etc.
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Encarta Encyclopedia defines biophysics as “Biophysics, interdisciplinary study of biological phenomena and problems, using the principles and techniques of physics.” Biophysics studies only the biological problems and structure of molecules in living organism in light of the techniques derived from physics. One of the best achievements of biophysics is the structure of DNA (Deoxyribonucleic Acid).
Mechanics is the branch of physics which deals with the motion of material objects under the influence of forces. Mechanics has been divided into two main branches: Classical mechanics and Quantum mechanics. Classical mechanics deals with the laws of motion of physical objects and the forces that cause the motion, while quantum mechanics is the branch of physics which deals with the behaviour of smallest particles i.e., electrons, neutrons and protons. According to Encarta dictionary, “Quantum mechanics is the study evolved in an effort to explain the behaviour of atoms and subatomic particles, which do not obey the laws of classical Newtonian mechanics.”
The word acoustics has been derived from a Greek word akouen, meaning to hear. Hence, we can define acoustics as a branch of physics, which studies how sound is produced, transmitted, received and controlled, is called acoustics. It also deals with the effects of sounds in various mediums i.e., gases, liquids and solids.
Optics is the branch of physics, which deals with the propagation, behaviour and properties of light. Encarta Encyclopedia defines Optics as “a branch of physical science dealing with the propagation and behavior of light. In a general sense, light is that part of the electromagnetic spectrum that extends from X rays to microwaves and includes the radiant energy that produces the sensation of vision.”
Thermodynamics is the branch of physics, which deals with the study of heat and its relation with energy and work. According to National Aeronautics and Space Administration, USA, “Thermodynamics is the study of effects of work, heat and energy on a system. Thermodynamics is only concerned with large scale observations.”
The word astrophysics is a combination of two words astro which means star, while the word phisis means nature. Thus, astrophysics can be defined as a branch of astronomy which is concerned with the study of universe i.e., stars, galaxies and planets using the laws of physics.